The enzymatic redox reactions in natural photosynthesis rely much on the participation of cofactors, with reduced nicotinamide adenine dinucleotide/nicotinamide adenine dinucleotide phosphate (NADH/NADPH) or their oxidized form (NAD⁺/NADP⁺) as an important redox power. The photocatalytic regeneration of expensive and unstable NADH/NADPH in vitro is an important process in enzymatic reduction and has attracted much research attention. Though different types of photocatalysts have been developed for photocatalytic NADH/NADPH regeneration, the efficiency is still relatively low. To elucidate the key factors affecting the performance of photocatalytic NADH/NADPH regeneration is helpful to rationally design the photocatalyst and improve the photocatalytic efficiency. In this paper, we overview the recent progress in photocatalytic NADH/NADPH regeneration with the focus on the strategies to improve the visible light adsorption, the charge separation and migration efficiency, as well as the surface reaction, which jointly determine the overall photocatalytic regeneration efficiency. The potential development of photocatalytic NADH/NADPH regeneration and photocatalytic-enzymatic-coupling system is prospected finally.

Carbon dioxide fixation presents a potential solution for mitigating the greenhouse gas issue. During carbon dioxide fixation, C1 compound reduction requires a high energy supply. Thermodynamic calculations suggest that the energy source for cofactor regeneration plays a vital role in the effective enzymatic C1 reduction. Hydrogenase utilizes renewable hydrogen to achieve the regeneration and supply cofactor nicotinamide adenine dinucleotide (NADH), providing a driving force for the reduction reaction to reduce the thermodynamic barrier of the reaction cascade, and making the forward reduction pathway thermodynamically feasible. Based on the regeneration of cofactor NADH by hydrogenase, and coupled with formaldehyde dehydrogenase and formolase, a favorable thermodynamic mode of the C1 reduction pathway for reducing formate to dihydroxyacetone (DHA) was designed and constructed. This resulted in accumulation of 373.19 μmol·L^–1 DHA after 2 h, and conversion reaching 7.47%. These results indicate that enzymatic utilization of hydrogen as the electron donor to regenerate NADH is of great significance to the sustainable and green development of bio-manufacturing because of its high economic efficiency, no by-products, and environment-friendly operation. Moreover, formolase efficiently and selectively fixed the intermediate formaldehyde (FALD) to DHA, thermodynamically pulled formate to efficiently reduce to DHA, and finally stored the low-grade renewable energy into chemical energy with high energy density.

Membrane gas separation is considered an energy-saving technique to extract He from natural gas due to no phase change and room temperature operation. However, the membrane performance was strongly limited by the trade-off between permeance and selectivity. Herein, novel 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA)-2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (APAF)-5-amino-2-(4-aminobenzene)benzimidazole (BIA) asymmetric membranes with a thickness of 300 nm were successfully prepared by the non-solvent induced phase separation method. The membrane performance was modulated by regulating dope solution compositions (e.g., tetrahydrofuran and polymer concentration). The ideal He/CH₄ selectivity was 124 and the optimized He permeance reached 87 GPU, beyond the current upper bound. He/CH₄ selectivity was 75 and He permeance was 73 GPU for the binary mixture feed containing 0.2 mol % He. The membrane showed good resistance to CO₂ and C₂H₆, which are the typical impurities in natural gas. The 6FDA-APAF-BIA membranes have good stability (> 160 h), which can provide great potential in He extraction from natural gas.

Organic matter-induced mineralization is a green and versatile method for synthesizing hybrid nanostructured materials, where the material properties are mainly influenced by the species of natural biomolecules, linear synthetic polymer, or small molecules, limiting their diversity. Herein, we adopted dendrimer poly(amidoamine) (PAMAM) as the inducer to synthesize organosilica-PAMAM network (OSPN) capsules for mannose isomerase (MIase) encapsulation based on a hard-templating method. The structure of OSPN capsules can be precisely regulated by adjusting the molecular weight and concentration of PAMAM, thereby demonstrating a substantial impact on the kinetic behavior of the MIase@OSPN system. The MIase@OSPN system was used for catalytic production of mannose from D-fructose. A mannose yield of 22.24% was obtained, which is higher than that of MIase in organosilica network capsules and similar to that of the free enzyme. The overall catalytic efficiency (k_cat/K_m) of the MIase@OSPN system for the substrate D-fructose was up to 0.556 s⁻¹·mmol⁻¹·L. Meanwhile, the MIase@OSPN system showed excellent stability and recyclability, maintaining more than 50% of the yield even after 12 cycles.

Bifunctional metal/zeolite materials are some of the most suitable catalysts for the direct hydroalkylation of benzene to cyclohexylbenzene. The overall catalytic performance of this reaction is strongly influenced by the hydrogenation, which is dependent on the metal sizes. Thus, systematically investigating the metal size effects in the hydroalkylation of benzene is essential. In this work, we successfully synthesized Ru and Pd nanoparticles on Sinopec Composition Materials No.1 zeolite with various metal sizes. We demonstrated the size-dependent catalytic activity of zeolite-supported Ru and Pd catalysts in the hydroalkylation of benzene, which can be attributed to the size-induced hydrogen spillover capability differences. Our work presents new insights into the hydroalkylation reaction and may open up a new avenue for the smart design of advanced metal/zeolite bi-functional catalysts.

The urgent need for sustainable waste management has led to the exploration of upcycling waste plastics and biomass as viable solutions. In 2018, global plastic production reached 359 million tonnes, with an estimated 12000 million tonnes projected to be delivered and disposed of in landfills by 2050. Unfortunately, current waste management practices result in only 19.5% of plastics being recycled, while the rest is either landfilled (55%) or incinerated (25.5%). The improper disposal of plastics contributes to issues such as soil and groundwater contamination, air pollution, and wildlife disturbance. On the other hand, biomass has the potential to deliver around 240 exajoules of energy per year by 2060. However, its current utilization remains relatively small, with only approximately 9% of biomass-derived energy being consumed in Europe in 2017. This review explores various upcycling methods for waste plastics and biomass, including mechanical, chemical, biological, and thermal approaches. It also highlights the applications of upcycled plastics and biomass in sectors such as construction, packaging, energy generation, and chemicals. The environmental and economic benefits of upcycling are emphasized, including the reduction of plastic pollution, preservation of natural resources, carbon footprint reduction, and circular economy advancement.

Regulation of aluminum distribution in zeolite framework is an effective method for improving its catalytic performance for propane aromatization. Herein, we found that recrystallization and post-realuminization of ZSM-5 cannot only create hollow structures to enhance the diffusion ability, but also adjust the content and position of paired aluminum species in its framework. Various characterizations results confirmed that increase of paired aluminum content and inducement of more aluminum atoms sited in the intersection cavity are beneficial to the formation of aromatic products in propane aromatization. As a result, the hollow-structured ZSM-5 zeolite with more paired aluminum (H-200-hollow) showed higher propane conversion and aromatics selectivity than other samples at the same conditions. The catalytic performance of H-200-hollow can be further improved by ion-exchanging with a small amount of Ga(III) species. The propane conversion and aromatics selectivity of Ga-200-hollow reached as high as 95% and 70%, respectively, at 540 °C and 1 atm.

This study utilized a thermogravimetric analyzer to assess the thermal decomposition behaviors and kinetics properties of vacuum residue (VR) and low-density polyethylene (LDPE) polymers. The kinetic parameters were calculated using the Friedman technique. To demonstrate the interactive effects between LDPE and VR during the co-pyrolysis process, the disparity in mass loss and mass loss rate between the experimental and calculated values was computed. The co-pyrolysis curves obtained through estimation and experimentation exhibited significant deviations, which were influenced by temperature and mixing ratio. A negative synergistic interaction was observed between LDPE and VR, although this inhibitory effect could be mitigated or eliminated by reducing the LDPE ratio in the mixture and increasing the co-pyrolysis temperature. The co-pyrolysis process resulted in a reduction in carbon residue, which could be attributed to the interaction between LDPE and the heavy fractions, particularly resin and asphaltene, present in VR. These findings align with the pyrolysis behaviors exhibited by the four VR fractions. Furthermore, it was observed that the co-pyrolysis process exhibited lower activation energy as the VR ratio increased, indicating a continuous enhancement in the reactivity of the mixed samples during co-pyrolysis.

Amino acids are important nitrogen carriers in biomass and entail a broad spectrum of industrial uses, most notably as food additives, pharmaceutical ingredients, and raw materials for bio-based plastics. Attaining detailed information in regard to the fragmentation of amino acids is essential to comprehend the nitrogen transformation chemistry at conditions encountered during hydrothermal and pyrolytic degradation of biomass. The underlying aim of this review is to survey literature studies pertinent to the complex structures of amino acids, their formation yields from various categories of biomass, and their fragmentation routes at elevated temperatures and in the aqueous media. Two predominant degradation reactions ensue in the decomposition of amino acids, namely deamination and decarboxylation. Notably, minor differences in structure can greatly affect the fate for each amino acid. Moreover, amino acids, being nitrogen-rich compounds, play pivotal roles across various fields. There is a growing interest in producing varied types and configurations of amino acids. Microbial fermentation appears to a viable approach to produce amino acids at an industrial scale. One innovative method under investigation is catalytic synthesis using renewable biomass as feedstocks. Such a method taps into the inherent nitrogen in biomass sources like chitin and proteins, eliminating the need for external nitrogen sources. This environmentally friendly approach is in line with green chemistry principles and has been gathering momentum in the scientific community.

The nitridation reaction of calcium carbide and N₂ at high temperatures is the key step in the production of lime-nitrogen. However, the challenges faced by this process, such as high energy consumption and poor product quality, are mainly attributed to the lack of profound understanding of the reaction. This study aimed to improve this process by investigating the non-isothermal kinetics and reaction characteristics of calcium carbide nitridation reaction at different heating rates (10, 15, 20, and 30 °C·min⁻¹) using thermogravimetric analysis. The kinetic equation for the nitridation reaction of additive-free calcium carbide sample was obtained by combining model-free methods and model-fitting method. The effect of different calcium-based additives (CaCl₂ and CaF₂) on the reaction was also investigated. The results showed that the calcium-based additives significantly reduced reaction temperature and activation energy E_a by about 40% with CaF₂ and by 55%–60% with CaCl₂. The reaction model f(α) was also changed from contracting volume (R3) to 3-D diffusion models with D3 for CaCl₂ and D4 for CaF₂. This study provides valuable information on the mechanism and kinetics of calcium carbide nitridation reaction and new insights into the improvement of the lime-nitrogen process using calcium-based additives.

During steam reforming, the performance of a catalyst and amount/property of coke are closely related to reaction intermediates reaching surface of a catalyst. Herein, modification of reaction intermediates by placing Mg-Al-hydrotalcite above Ni/KIT-6 catalyst in steam reforming of glycerol was conducted at 300 to 600 °C. The results revealed that the catalytic activity of Ni/KIT-6 in the lower bed was enhanced with either Mg₁-Al₅-hydrotalcite (containing more acidic sites) or Mg₅-Al₁-hydrotalcite (containing more alkaline sites) as upper-layer catalyst. The in situ infrared characterization of steam reforming demonstrated that Mg-Al-hydrotalcite catalyzed the deoxygenation of glycerol, facilitating the reforming of the partially deoxygenated intermediates over Ni/KIT-6. Mg-Al-hydrotalcite as protective catalyst, however, did not protect the Ni/KIT-6 from formation of more coke. Nonetheless, this did not lead to further deactivation of Ni/KIT-6 while Mg₅-Al₁-hydrotalcite even substantially enhanced the catalytic stability, even though the coke was much more significant than that in the use of single Ni/KIT-6 (52.7% vs. 28.6%). The reason beneath this was change of the property of coke from more aliphatic to more aromatic. Mg₅-Al₁-hydrotalcite catalyzed dehydration of glycerol, producing dominantly reaction intermediates bearing C=C, which formed the catalytic coke of with carbon nanotube as the main form with smooth outer walls as well as higher aromaticity, C/H ratio, crystallinity, crystal carbon size, thermal stability, and resistivity toward oxidation on Ni/KIT-6 in the lower bed. In comparison, the abundance of acidic sites on Mg₁-Al₅-hydrotalcite catalyzed the formation of more oxygen-containing species, leading to the formation of carbon nanotubes of rough surface on Ni/KIT-6.

Methanol-to-olefins, as a promising non-oil pathway for the synthesis of light olefins, has been successfully industrialized. The accurate prediction of process variables can yield significant benefits for advanced process control and optimization. The challenge of this task is underscored by the failure of traditional methods in capturing the complex characteristics of industrial processes, such as high nonlinearities, dynamics, and data distribution shift caused by diverse operating conditions. In this paper, we propose a novel hybrid spatial-temporal deep learning prediction model to address these issues. Firstly, a unique data normalization technique called reversible instance normalization is employed to solve the problem of different data distributions. Subsequently, convolutional neural network integrated with the self-attention mechanism are utilized to extract the temporal patterns. Meanwhile, a multi-graph convolutional network is leveraged to model the spatial interactions. Afterward, the extracted temporal and spatial features are fused as input into a fully connected neural network to complete the prediction. Finally, the outputs are denormalized to obtain the ultimate results. The monitoring results of the dynamic trends of process variables in an actual industrial methanol-to-olefins process demonstrate that our model not only achieves superior prediction performance but also can reveal complex spatial-temporal relationships using the learned attention matrices and adjacency matrices, making the model more interpretable. Lastly, this model is deployed onto an end-to-end Industrial Internet Platform, which achieves effective practical results.

We report results from computational modeling of the relative stability of germanosilicate SCM-15 structure due to different distribution of germanium heteroatoms in the double four-member rings (D4Rs) of the framework and the orientation of the structure directing agent (SDA) molecules in the as-synthesized zeolite. The calculated relative energies of the bare zeolite framework suggest that structures with germanium ions clustered in the same D4Rs, e.g., with large number of Ge–O–Ge contacts, are the most stable. The simulations of various orientations of the SDA in the pores of the germanosilicate zeolite show different stability order—the most stable models are the structures with germanium spread among all D4Rs. Thus, for SCM-15 the stabilization due to the presence of the SDA and their orientation, is thermodynamic factor directing both the formation of specific framework type and Ge distribution in the framework during the synthesis. The relative stability of bare structures with different germanium distribution is of minor importance. This differs from SCM-14 germanosilicate, reported earlier, for which the stability order is preserved in presence of SDA. Thus, even for zeolites with the same chemical composition and SDA, the characteristics of their framework lead to different energetic preference for germanium distribution.

Hydrogenolysis has been explored as a promising approach for plastic chemical recycling. Noble metals, such as Ru and Pt, are considered effective catalysts for plastic hydrogenolysis, however, they result in a high yield of low-value gaseous products. In this research, an efficient bimetallic catalyst was developed by separate impregnation of Ni and Ru on SiO₂ support resulting in liquid products yield of up to 83.1 C % under mild reaction conditions, compared to the 65.5 C % yield for the sole noble metal catalyst. The carbon distribution of the liquid products from low density polyethylene hydrogenolysis with Ni-modified catalyst also shifted to a heavier fraction, compared to that with Ru catalyst. Meanwhile, the NiRu catalyst exhibited excellent performance in suppressing the cleavage of the end-chain C–C bond, leading to a methane yield of only 10.4 C %, which was 69% lower than that of the Ru/SiO₂ catalyst. Temperature programmed reduction and desorption of hydrogen and propane were further conducted to reveal the detailed mechanism of low density polyethylene hydrogenolysis over the bimetallic catalyst. The results suggested that the Ni-Ru alloy exhibited stronger H adsorption properties indicating improved hydrogen coverage on the catalyst surface thus enhancing the desorption of reaction intermediates. The carbon number distribution was ultimately skewed toward heavier liquid products.

Eucalyptus species are extensively cultivated trees commonly used for timber production, firewood, paper manufacturing, and essential nutrient extraction, while lacking consumption of the leaves increases soil acidity. The objective of this study was to recover bio-oil through microwave pyrolysis of eucalyptus camaldulensis leaves. The effects of microwave power (450, 550, 650, 750, and 850 W), pyrolysis temperature (500, 550, 600, 650, and 700 °C), and silicon carbide amount (10, 25, 40, 55, and 70 g) on the products yields and bio-oil constituents were investigated. The yields of bio-oil, gas, and residue varied within the ranges of 19.8–39.25, 33.75–46.7, and 26.0–33.5 wt %, respectively. The optimal bio-oil yield of 39.25 wt % was achieved at 650 W, 600 °C, and 40 g. The oxygenated derivatives, aromatic compounds, aliphatic hydrocarbons, and phenols constituted 40.24–74.25, 3.25–23.19, 0.3–9.77, and 1.58–7.75 area % of the bio-oils, respectively. Acetic acid (8.17–38.18 area %) was identified as a major bio-oil constituent, and hydrocarbons with carbon numbers C₁ and C₂ were found to be abundant. The experimental results demonstrate the potential of microwave pyrolysis as an eco-friendly and efficient way for converting eucalyptus waste into valuable bio-oil, contributing to the sustainable utilization of biomass resources.

The aluminum-water system is a promising propellant due to high energy and low signal characteristics, and the gel form is easier to store and utilize. In this work, hydrogels of water and aluminum particles were prepared using the low-molecular-weight gellant agarose. The various physical properties of gel systems, including the water loss rate, phase transition temperature, and centrifugal stability at different gellant and aluminum contents, were examined. Rheological properties were assessed through shear thinning tests, thixotropy tests, strain sweep analysis, and frequency sweep experiments. The microstructure of the gel was obtained through scanning electron microscopy images. The results show that the aluminum-hydrogel network structure is composed of micron-scale aluminum and agarose nanosheets, and the unique micro-nanostructure endows the gel with excellent mechanical strength and thermal stability, which improve with increasing gellant and aluminum contents. Notably, the gel with 2% agarose and 20% aluminum had the best performance; the storage modulus reached 90647 Pa, which was within the linear viscoelastic region, and the maximum withstand pressure was 111.2 kPa, which was 118.8% greater than that of the pure hydrogel. Additionally, the gel demonstrates remarkable shear thinning behavior and can undergo gel-sol transformation upon shearing or heating to exceeding 114 °C.

Sodium-ion batteries (SIBs) have garnered significant interest in energy storage due to their similar working mechanism to lithium ion batteries and abundant reserves of sodium resource. Exploring facile synthesis of a carbon-based anode materials with capable electrochemical performance is key to promoting the practical application of SIBs. In this work, a combination of petroleum pitch and recyclable sodium chloride is selected as the carbon source and template to obtain hard carbon (HC) anode for SIBs. Carbonization times and temperatures are optimized by assessing the sodium ion storage behavior of different HC materials. The optimized HC exhibits a remarkable capacity of over 430 mAh·g^–1 after undergoing full activation through 500 cycles at a density of current of 0.1 A·g^–1. Furthermore, it demonstrates an initial discharge capacity of 276 mAh·g^–1 at a density of current of 0.5 A·g^–1. Meanwhile, the optimized HC shows a good capacity retention (170 mAh·g^–1 after 750 cycles) and a remarkable rate ability (166 mAh·g^–1 at 2 A·g^–1). The enhanced capacity is attributed to the suitable degree of graphitization and surface area, which improve the sodium ion transport and storage.

Nowadays, global warming caused by the increasing levels of CO₂ has become a serious environmental problem. Membrane separation technology has demonstrated its promising potential in carbon capture due to its easy operation, energy-efficientness and high efficiency. Interfacial polymerization process, as a facile and well-established technique for preparing membranes with a thin selective layer, has been widely used for fabricating commercial reverse osmosis and nanofiltration membranes in water treatment domain. To push forward such an interfacial polymerization process in the research of CO₂ separation membranes, herein we make a review on the regulation and research progress of the interfacial polymerization membranes for CO₂ separation. First, a comprehensive and critical review of the progress in the monomers, nanoparticles and interfacial polymerization process optimization for preparing CO₂ separation membrane is presented. In addition, the potential of molecular dynamics simulation and machine learning in accelerating the screen and design of interfacial polymerization membranes for CO₂ separation are outlined. Finally, the possible challenges and development prospects of CO₂ separation membranes by interfacial polymerization process are proposed. It is believed that this review can offer valuable insights and guidance for the future advancement of interfacial polymerization membranes for CO₂ separation, thereby fostering its development.

Typically, the hydroxide agents, such as sodium hydroxide and potassium hydroxide, which have corrosive properties, are used in the carbon activation process. In this study, potassium oxalate (K₂C₂O₄), a less toxic and non-corrosive activating reagent, was used to synthesize activated carbon from the solid residue after autohydrolysis treatment. The effect of the autohydrolysis treatment and the ratio of the K₂C₂O₄/solid residue are presented in this study. Moreover, the comparison between the activated carbon from bamboo and biochar from the solid residue are also reported. The resulting activated carbon from the solid residue exhibited a high surface area of up to 1432 m²·g^–1 and a total pore volume of up to 0.88 cm³·g^–1. The autohydrolysis treatment enhanced the microporosity properties compared to those without pretreatment of the activated carbon. The microporosity of the activated carbon from the solid residue was dominated by the pore width at 0.7 nm, which is excellent for CO₂ storage. At 25 °C and 1.013 × 10⁵ Pa, the CO₂ captured reached up to 4.1 mmol·g^–1. On the other hand, the ratio between K₂C₂O₄ and the solid residue has not played a critical role in determining the porosity properties. The ratio of the K₂C₂O₄/solid residue of 2 could help the carbon material reach a highly microporous textural property that produces a high carbon capture capacity. Our finding proved the benefit of using the solid residue from the autohydrolysis treatment as a precursor material and offering a more friendly and sustainable activation carbon process.

Unraveling the structure-activity relationship and improving the catalytic performance is paramount in propane dehydro-aromatization reactions. Herein, a tandem catalyst with high propane dehydro-aromatization reaction performance was prepared via coupling the PtFe@S-1 with Zn/ZSM-5 zeolites (PtFe@S-1&1.0Zn/ZSM-5), which exhibits high dehydrogenation activity, aromatics selectivity (~60% at ~78% propane conversion), and stability. The addition of zinc inhibits the cleavage of C₆⁼ intermediates on ZSM-5 and promotes the aromatization pathway by weakening zeolite acid strength, significantly improving the selectivity to aromatics. This understanding of the structure-activity relationship in propane dehydro-aromatization reaction helps develop future high-performance catalysts.

The fabrication of suitable MFI zeolites to effectively produce para-xylene through the alkylation between toluene and methanol is highly desired. Here, the two-dimensional pillared MFI zeolite was modified by silicalite-1, and its morphology and structure were systematically investigated by tuning the concentration of Si species during the secondary crystallization process. The MFI zeolites were characterized by X-ray diffraction, transmission electron microscopy, pyridine-infrared and N₂ adsorption-desorption isotherms. The characterization results showed that the external Brønsted acid sites of surface passivated P-MFI-x samples have been successfully shielded. Interestingly, the P-MFI-23 showed long lifetime and high selectivity of para-xylene (about 35%) based on the cooperation between opened interlamellar structure and passivated silicalite-1 layer. It was found that the accumulated hard coke in the interior of MFI zeolites not only blocked the channels of zeolites but also covered the acidic sites, resulting in the deactivation of catalyst. Furthermore, the highest selectivity of para-xylene (about 48%) can be achieved for P-MFI-30 under harsh reaction condition, which also exhibited excellent regeneration property in the alkylation reaction between toluene and methanol. The strategy described in present research may open a window for the design of other advanced materials.

The applicability of the life cycle assessment (LCA) to the Fenton process should be considered not only at the laboratory-scale but also at the full-scale. In this study, the LCA process was applied to evaluate the homogeneous Fenton process for the treatment of high salinity pharmaceutical wastewater. The potential environmental impacts were calculated using Simapro software implementing the CML 2001 methodology with normalization factors of 1995 world. Foreground data obtained directly from the full-scale wastewater treatment plant and laboratory were used to conduct a life cycle inventory analysis, ensuring highly accurate results. By normalized results, the Fenton process reveals sensitive indicators, primarily toxicity indicators (human toxicity, freshwater aquatic toxicity, and marine aquatic toxicity), as well as acidification and eutrophication impacts, contributed by hydrogen peroxide and iron sludge incineration, respectively. Overall, hydrogen peroxide and iron sludge incineration contribute significantly, accounting for at least 78% of these indicators. In sludge treatment phase, treatment of iron mud and infrastructure of hazardous waste incineration plants were the key contributors of environmental impacts, adding up to more than 95%. This study suggests the need to develop efficient oxidation processes and effective iron sludge treatment methods to reduce resource utilization and improve environmental benefits.

We proposed a facile synthesis of single-Ni-atom catalysts on low-cost porous carbon using a calcination method at the temperatures of 850–1000 °C, which were used for CO₂ electrochemical reduction to CO. The porous carbon was prepared by carbonizing cheap and abundant humic acid. The structural characterizations of the as-synthesized catalysts and their electrocatalytic performances were analyzed. The results showed that the single-Ni-atom catalyst activated at 950 °C showed an optimum catalytic performance, and it reached a CO Faradaic efficiency of 91.9% with a CO partial current density of 6.9 mA·cm⁻² at −0.9 V vs. reversible hydrogen electrode (RHE). Additionally, the CO Faradaic efficiency and current density of the optimum catalyst changed slightly after 8 h of continuous operation, suggesting that it possessed an excellent stability. The structure-activity relations indicate that the variation in the CO₂ electrochemical reduction performance for the as-synthesized catalysts is ascribed to the combined effects of the increase in the content of pyrrolic N, the evaporation of Ni and N, the decrease in pore volume, and the change in graphitization degree.

Removal of boric acid from seawater and wastewater using reverse osmosis membrane technologies is imperative and yet remains inadequately addressed by current commercial membranes. Existing research efforts performed post-modification of reverse osmosis membranes to enhance boron rejection, which is usually accompanied by substantial sacrifice in water permeability. This study delves into the surface engineering of low-pressure reverse osmosis membranes, aiming to elevate boron removal efficiency while maintaining optimal salt rejection and water permeability. Membranes were modified by the self-polymerization and co-deposition of dopamine and polystyrene sulfonate at varying ratios and concentrations. The surfaces became smoother and more hydrophilic after modification. The optimum membrane exhibited a water permeability of 9.2 ± 0.1 L·m⁻²·h⁻¹·bar⁻¹, NaCl rejection of 95.8% ± 0.3%, and boron rejection of 49.7% ± 0.1% and 99.6% ± 0.3% at neutral and alkaline pH, respectively. The water permeability is reduced by less than 15%, while the boron rejection is 3.7 times higher compared to the blank membrane. This research provides a promising avenue for enhancing boron removal in reverse osmosis membranes and addressing water quality concerns in the desalination process.

A novel, cheap and highly efficient Ni-Co/Mo₂C/Co₆Mo₆C₂@C nanocomposite has been successfully constructed through simple one-step carbonization method in a nitrogen atmosphere. Polyethyleneimine in the precursor can effectively anchor molybdenum-based Keggin-type polyoxometallate and NiCo-layered double hydroxide through electrostatic and coordination interactions, which avoids the aggregation of catalyst particles during the pyrolysis process. After optimization, the obtained Ni-Co/Mo₂C/Co₆Mo₆C₂@C possesses small size (3–8 nm), large specific surface area and hierarchical pore structure. More importantly, Ni-Co/Mo₂C/Co₆Mo₆C₂@C presents remarkable hydrogen evolution reaction activity with low overpotentials in 0.5 mol·L^–1 H₂SO₄ (102.3 mV) and 1 mol·L^–1 KOH (95 mV) to afford the current density of 10 mA·cm^–2, as well as small Tafel slopes of 82.49 and 99.92 mV·dec^–1, respectively. Simultaneously, this catalyst also shows outstanding stability for 12 h without a significant change in current density. The excellent catalytic performance of Ni-Co/Mo₂C/Co₆Mo₆C₂@C can put down to the synergistic effect between multiple components and the small size of the catalyst. This work provides unique insights into the preparation of efficient transition metal-based catalysts for HER.

Lignin, an abundant aromatic polymer in nature, has received significant attention for its potential in the production of bio-oils and chemicals owing to increased resource availability and environmental issues. The hydrodeoxygenation of guaiacol, a lignin-derived monomer, can produce cyclohexanol, a nylon precursor, in a carbon-negative and environmentally friendly manner. This study explored the porous properties and the effects of activation methods on the Ru-based catalyst supported by environmentally friendly and cost-effective hydrochar. Highly selective cleavage of C_aryl–O bonds was achieved under mild conditions (160 °C, 0.2 MPa H₂, and 4 h), and alkali activation further improved the catalytic activity. Various characterization methods revealed that hydrothermal treatment and alkali activation relatively contributed to the excellent performance of the catalysts and influenced their porous structure and Ru dispersion. X-ray photoelectron spectroscopy results revealed an increased formation of metallic ruthenium, indicating the effective regulation of interaction between active sites and supports. This synergistic approach used in this study, involving the valorization of cellulose-derived hydrochar and the selective production of nylon precursors from lignin-derived guaiacol, indicated the comprehensive and sustainable utilization of biomass resources.

The engineering of microbial cell factories for the production of high-value chemicals from renewable resources presents several challenges, including the optimization of key enzymes, pathway fluxes and metabolic networks. Addressing these challenges involves the development of synthetic auxotrophs, a strategy that links cell growth with enzyme properties or biosynthetic pathways. This linkage allows for the improvement of enzyme properties by in vivo directed enzyme evolution, the enhancement of metabolic pathway fluxes under growth pressure, and remodeling of metabolic networks through directed strain evolution. The advantage of employing synthetic auxotrophs lies in the power of growth-coupled selection, which is not only high-throughput but also labor-saving, greatly simplifying the development of both strains and enzymes. Synthetic auxotrophs play a pivotal role in advancing microbial cell factories, offering benefits from enzyme optimization to the manipulation of metabolic networks within single microbes. Furthermore, this strategy extends to coculture systems, enabling collaboration within microbial communities. This review highlights the recently developed applications of synthetic auxotrophs as microbial cell factories, and discusses future perspectives, aiming to provide a practical guide for growth-coupled models to produce value-added chemicals as part of a sustainable biorefinery.

As an important technology in fine chemical production, the selective hydrogenation of α,β-unsaturated aldehydes has attracted much attention in recent years. In the process of α,β-unsaturated aldehyde hydrogenation, a conjugated system is formed between >C=C< and >C=O, leading to hydrogenation at both ends of the conjugated system, which competes with each other and results in more complex products. Therefore, improving the reaction selectivity is also difficult in industrial fields. Recently, many researchers have reported that surface-active sites on catalysts play a crucial role in α,β-unsaturated aldehyde hydrogenation. This review attempts to summarize recent advances in understanding the effects of surface-active sites (SASs) over metal catalysts for enhancing the process of hydrogenation. The construction strategies and roles of SASs for hydrogenation catalysts are summarized. Particular attention has been given to the adsorption configuration and transformation mechanism of α,β-unsaturated aldehydes on catalysts, which contributes to understanding the relationship between SASs and hydrogenation activity. In addition, recent advances in metal-supported catalysts for the selective hydrogenation of α,β-unsaturated aldehydes to understand the role of SASs in hydrogenation are briefly reviewed. Finally, the opportunities and challenges will be highlighted for the future development of the precise construction of SASs.

Ammonia is a vital component in the fertilizer and chemical industries, as well as serving as a significant carrier of renewable hydrogen energy. Compared with the industry’s principal technique, the Haber-Bosch method, for ammonia synthesis, electro/photocatalytic ammonia synthesis is increasingly recognized as a viable and eco-friendly alternative. This method enables distributed small-scale deployment and can be powered by sustainable renewable energy sources. However, the efficiency of electro/photocatalytic nitrogen reduction reaction is hindered by the challenges in activating the N≡N bond and nitrogen’s low solubility, thereby limiting its large-scale industrial applications. In this review, recent advancements in electro/photocatalytic nitrogen reduction are summarized, encompassing the complex reaction mechanisms, as well as the effective strategies for developing electro/photocatalytic catalysts and advanced reaction systems. Furthermore, the energy efficiency and economic analysis of electro/photocatalytic nitrogen fixation are deeply discussed. Finally, some unsolved challenges and potential opportunities are discussed for the future development of electro/photocatalytic ammonia synthesis.