High entropy materials (HEMs) have developed rapidly in the field of electrocatalytic water-electrolysis for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) due to their unique properties. In particular, HEM catalysts are composed of many elements. Therefore, they have rich active sites and enhanced entropy stability relative to single atoms. In this paper, the preparation strategies and applications of HEM catalysts in electrochemical water-electrolysis are reviewed to explore the stabilization of HEMs and their catalytic mechanisms as well as their application in support green hydrogen production. First, the concept and four characteristics of HEMs are introduced based on entropy and composition. Then, synthetic strategies of HEM catalysts are systematically reviewed in terms of the categories of bottom-up and top-down. The application of HEMs as catalysts for electrochemical water-electrolysis in recent years is emphatically discussed, and the mechanisms of improving the performance of electrocatalysis is expounded by combining theoretical calculation technology and ex-situ/in situ characterization experiments. Finally, the application prospect of HEMs is proposed to conquer the challenges in HEM catalyst fabrications and applications.
The Haber-Bosch process is the most widely used synthetic ammonia technology at present. Since its invention, it has provided an important guarantee for global food security. However, the traditional Haber-Bosch ammonia synthesis process consumes a lot of energy and causes serious environmental pollution. Under the serious pressure of energy and environment, a green, clean, and sustainable ammonia synthesis route is urgently needed. Electrochemical synthesis of ammonia is a green and mild new method for preparing ammonia, which can directly convert nitrogen or nitrate into ammonia using electricity driven by solar, wind, or water energy, without greenhouse gas and toxic gas emissions. Herein, the basic mechanism of the nitrogen reduction reaction (NRR) to ammonia and nitrate reduction reaction (
As the intersection of disciplines deepens, the field of battery modeling is increasingly employing various artificial intelligence (AI) approaches to improve the efficiency of battery management and enhance the stability and reliability of battery operation. This paper reviews the value of AI methods in lithium-ion battery health management and in particular analyses the application of machine learning (ML), one of the many branches of AI, to lithium-ion battery state of health (SOH), focusing on the advantages and strengths of neural network (NN) methods in ML for lithium-ion battery SOH simulation and prediction. NN is one of the important branches of ML, in which the application of NNs such as backpropagation NN, convolutional NN, and long short-term memory NN in SOH estimation of lithium-ion batteries has received wide attention. Reports so far have shown that the utilization of NN to model the SOH of lithium-ion batteries has the advantages of high efficiency, low energy consumption, high robustness, and scalable models. In the future, NN can make a greater contribution to lithium-ion battery management by, first, utilizing more field data to play a more practical role in health feature screening and model building, and second, by enhancing the intelligent screening and combination of battery parameters to characterize the actual lithium-ion battery SOH to a greater extent. The in-depth application of NN in lithium-ion battery SOH will certainly further enhance the science, reliability, stability, and robustness of lithium-ion battery management.
Solar-driven hydrogen production from seawater attracts great interest for its emerging role in decarbonizing global energy consumption. Given the complexity of natural seawater content, photocatalytic vapor splitting offers a low-cost and safe solution, but with a very low solar-to-hydrogen conversion efficiency. With a focus on cutting-edge photothermal–photocatalytic device design and system integration, the recent research advances on vapor splitting from seawater, as well as industrial implementations in the past decades were reviewed. In addition, the design strategies of the key processes were reviewed, including vapor temperature and pressure control during solar thermal vapor generation from seawater, capillary-fed vaporization with salt repellent, and direct photocatalytic vapor splitting for hydrogen production. Moreover, the existing laboratory-scale and industrial-scale systems, and the integration principles and remaining challenges in the future seawater-to-hydrogen technology were discussed.
The electrochemistry of cathode materials for sodium-ion batteries differs significantly from lithium-ion batteries and offers distinct advantages. Overall, the progress of commercializing sodium-ion batteries is currently impeded by the inherent inefficiencies exhibited by these cathode materials, which include insufficient conductivity, slow kinetics, and substantial volume changes throughout the process of intercalation and deintercalation cycles. Consequently, numerous methodologies have been utilized to tackle these challenges, encompassing structural modulation, surface modification, and elemental doping. This paper aims to highlight fundamental principles and strategies for the development of sodium transition metal oxide cathodes. Specifically, it emphasizes the role of various elemental doping techniques in initiating anionic redox reactions, improving cathode stability, and enhancing the operational voltage of these cathodes, aiming to provide readers with novel perspectives on the design of sodium metal oxide cathodes through the doping approach, as well as address the current obstacles that can be overcome/alleviated through these dopant strategies.
The use of two-dimensional (2D) layered metal-organic frameworks (MOFs) as self-sacrificial templates has been proven to be a successful method to create high-efficiency Selenium (Se)-containing electrocatalysts for overall water splitting. Herein, two strategies are then utilized to introduce Se element into the Co–Fe MOF, one being the etching of as-prepared MOF by SeO2 solution, and the other, the replacing of SCN− with SeCN− as the construction unit. The electrochemical activity of the pristine 2D MOF and their calcinated derivatives for catalyzing the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is evaluated and further discussed. It is found that the effect of introducing Se on improving electrochemical catalytic activity is significant for the HER process. Specifically, the calcinated derivative in the replacing method exhibits an overpotential of 235 mV for HER and 270 mV for OER at a current density of 10 mA/cm2. For comparing the two methods of introducing Se element into MOF, similar electrocatalytic activity can be achieved on the their calcinated derivatives. The high electrochemical performance of 2D CoFe-MOF derivatives may be resulted from the unique 2D hierarchical porous structure and strong synergistic effect between different components in the material.
Platinum (Pt)-based materials are still the most efficient and practical catalysts to drive the sluggish kinetics of cathodic oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). However, their catalysis and stability performance still need to be further improved in terms of corrosion of both carbon support and Pt catalyst particles as well as Pt loading reduction. Based on the developed synthetic strategies of alloying/nanostructuring Pt particles and modifying/innovating supports in developing conventional Pt-based catalysts, Pt single-atom catalysts (Pt SACs) as the recently burgeoning hot materials with a potential to achieve the maximum utilization of Pt are comprehensively reviewed in this paper. The design thoughts and synthesis of various isolated, alloyed, and nanoparticle-contained Pt SACs are summarized. The single-atomic Pt coordinating with non-metals and alloying with metals as well as the metal-support interactions of Pt single-atoms with carbon/non-carbon supports are emphasized in terms of the ORR activity and stability of the catalysts. To advance further research and development of Pt SACs for viable implementation in PEMFCs, various technical challenges and several potential research directions are outlined.
Great progress has been made in the electrochromic (EC) technology with potential applications in various fields. As one of the most promising EC materials, Prussian blue (PB) has attracted great attention due to its excellent EC performance, such as low cost, easy synthesis, rich color states, chemical stability, suitable redox potential, and fast color-switching kinetics. This review summarizes the recent progress in PB electrodes and devices, including several typical preparation techniques of PB electrodes, as well as the recent key strategies for enhancing EC performance of PB electrodes. Specifically, PB-based electrochromic devices (ECDs) have been widely used in various fields, such as smart windows, electrochromic energy storage devices (EESDs), wearable electronics, smart displays, military camouflage, and other fields. Several opportunities and obstacles are suggested for advancing the development of PB-based ECDs. This comprehensive review is expected to offer valuable insights for the design and fabrication of sophisticated PB-based ECDs, enabling their practical integration into real-world applications.
Using the electrochemical technology to split water molecules to produce hydrogen is the key to obtain green hydrogen for solving the energy crisis. The large-scale application of hydrogen evolution reaction (HER) in water dissociation requires a highly active catalyst. In this paper, the highly dispersed PtCo bimetallic nanoparticles loading on MXene (PtCo/MXene) were prepared by using a step-to-step reduction strategy. The mentioned PtCo/MXene catalyst exhibits a high current density of −100 mA/cm2 in an acidic medium with just a 152 mV overpotential. In addition, the PtCo/MXene catalyst also displays a superior stability. Computational analysis and experimental testing demonstrate that the electronic interaction between Pt and Co can effectively modify the electronic structure of the active site, thereby enhancing the inherent catalytic performance of the material. More importantly, MXene two-dimensional nanosheets can expose more active sites because of their large specific surface area. Furthermore, MXene substrate with excellent electrical conductivity and harmonious interfaces between PtCo and MXene enhance charge transfer efficiency and lower the reaction activation energy.
As a clean and efficient renewable energy source, solar energy has been rapidly applied worldwide. The growth rate of China’s installed capacity ranks first in the world. However, the life span of photovoltaic (PV) modules is 25 to 30 years, and the rapid development of installed capacity indicates that a large number of PV modules will be decommissioned in the future. Therefore, the ongoing treatment of the scrapped PV waste cells in the near future requires urgent plans and countermeasures. Proper recycling and disposal of decommissioned PV modules is a practical requirement for the sustainable development of the country and industry. Crystalline silicon (c-Si) solar cells currently occupy 85%–90% of the market share, and some scholars have begun to seek the utilization pathways of the waste Si in and outside the PV industry. In this paper, the research status of the separation and recycling process of crystalline Si PV modules is reviewed, and the recycling ways of crystalline silicon are particularly focused on. In addition, the current bottlenecks in the PV recycling industry in China are analyzed and some suggestions on the sustainable development of the PV industry are proposed.
Co-processing of biomass feedstock with petroleum feedstock in existing refineries is a promising technology that enables the production of low-carbon fuels, reduces dependence on petroleum feedstock, and utilizes the existing infrastructure in refinery. Much effort has been dedicated to advancing co-processing technologies. Though significant progress has been made, the development of co-processing is still hindered by numerous challenges. Therefore, it is important to systematically summarize up-to-date research activities on co-processing process for the further development of co-processing technologies. This paper provides a review of the latest research activities on co-processing biomass feedstock with petroleum feedstock utilizing fluid catalytic cracking (FCC) or hydrotreating (HDT) processes. In addition, it extensively discusses the influence of different types and diverse physicochemical properties of biomass feedstock on the processing of petroleum feedstock, catalysts employed in co-processing studies, and relevant projects. Moreover, it summarizes and discusses co-processing projects in pilot or larger scale. Furthermore, it briefly prospects the research trend of co-processing in the end.
Formic acid (FA) is a potential biomass resource of syngas with contents of carbon monoxide (CO, 60 wt.%) and hydrogen (H2, 4.4 wt.%). Among the technologies for FA conversion, the photoreforming of FA has received widespread attention due to its use of green solar energy conversion technology and mild reaction conditions. Herein, a V–W bimetallic solid solution, VxW1−xN1.5 with efficient co-catalytic properties was first and facilely synthesized. When CdS was used as a photocatalyst, the activity performance of the V0.1W0.9N1.5 system was over 60% higher than that of the W2N3 system. The computational simulations and experiments showed the V0.1W0.9N1.5 had great metallic features and large work functions, contributing a faster photo-generated carrier transfer and less recombination, finally facilitating a great performance in cocatalyst for syngas production in photoreforming FA. This work provides an approach to synthesizing novel transition metal nitrides for photocatalysis.
Exploring advanced platinum (Pt)-based electrocatalysts is vital for the widespread implementation of proton exchange membrane fuel cells (PEMFCs). Morphology control represents an effective strategy to optimize the behavior of Pt catalysts. In this work, an attempt is made to comprehensively review the effect of morphology control on the catalytic behavior of catalysts in the oxygen reduction reaction (ORR). First, the fundamental physicochemical changes behind morphology control, including exposing more active sites, generating appropriate lattice strains, and forming different crystalline surfaces, are highlighted. Then, recently developed strategies for tuning the morphologies of electrocatalysts, including core-shell structures, hollow structures, nanocages, nanowires, and nanosheets, are comprehensively summarized. Finally, an outlook on the future development of morphology control of Pt catalysts is presented, including rational design strategies, advanced in situ characterization techniques, novel artificial intelligence, and mechanical learning. This work is intended to provide valuable insights into designing the morphology and technological innovation of efficient redox electrocatalysts in fuel cells.
Interconnector is a critical component to construct solid oxide cells (SOCs) stack. Oxidation of metallic interconnectors and Cr poisoning caused by oxidation are important factors that lead to long-term performance degradation of SOCs. Coating on the interconnector surface is an important approach to inhibit the oxidation and Cr migration of the interconnector. Herein, (La0.75Sr0.25)0.95MnO3–δ (LSM) and Mn1.5Co1.5O4 (MCO) are used to fabricate the coatings of interconnector. Two advanced thermal spray technology, atmospheric plasma spraying (APS) and low-pressure plasma spray (LPPS), are adopted for the coating preparation. The electrochemical performance, rising and cooling cycle stability, and Cr diffusion inhibition performance of the coatings are tested and evaluated. The result indicates that MCO can generate more uniform and denser coatings than LSM. In addition, MCO coatings prepared by LPPS shows the best electrochemical performance, rising and cooling cycle stability, and Cr diffusion inhibition. The initial area specific resistance (ASR) is 0.0027 Ω·cm2 at 800 °C. After 4 cooling cycle tests, the ASR increases to 0.0032 Ω·cm2 but lower than other samples. Meanwhile, the relative intense of Cr at the interface of SUS430 with MCO coatings fabricated by LPPS is lower than that of MCO fabricated by APS after 4 rising and cooling cycle operations, showing more favorable Cr diffusion inhibition performance.
Lithium-ion batteries (LIBs) are widely used in transportation, energy storage, and other fields. The prediction of the remaining useful life (RUL) of lithium batteries not only provides a reference for health management but also serves as a basis for assessing the residual value of the battery. In order to improve the prediction accuracy of the RUL of LIBs, a two-phase RUL early prediction method combining neural network and Gaussian process regression (GPR) is proposed. In the initial phase, the features related to the capacity degradation of LIBs are utilized to train the neural network model, which is used to predict the initial cycle lifetime of 124 LIBs. The Pearson coefficient’s two most significant characteristic factors and the predicted normalized lifetime form a 3D space. The Euclidean distance between the test dataset and each cell in the training dataset and validation dataset is calculated, and the shortest distance is considered to have a similar degradation pattern, which is used to determine the initial Dual Exponential Model (DEM). In the second phase, GPR uses the DEM as the initial parameter to predict each test set’s early RUL (ERUL). By testing four batteries under different working conditions, the RMSE of all capacity estimation is less than 1.2%, and the accuracy percentage (AP) of remaining life prediction is more than 98%. Experiments show that the method does not need human intervention and has high prediction accuracy.
Proton exchange membrane fuel cells (PEMFCs) are playing irreplaceable roles in the construction of the future sustainable energy system. However, the insufficient performance of platinum (Pt)-based electrocatalysts for oxygen reduction reaction (ORR) hinders the overall efficiency of PEMFCs. Engineering the surface strain of catalysts is considered an effective way to tune their electronic structures and therefore optimize catalytic behavior. In this paper, insights into strain engineering for improving Pt-based catalysts toward ORR are elaborated in detail. First, recent advances in understanding the strain effects on ORR catalysts are comprehensively discussed. Then, strain engineering methodologies for adjusting Pt-based catalysts are comprehensively discussed. Finally, further information on the various challenges and potential prospects for strain modulation of Pt-based catalysts is provided.
NiFe (oxy)hydroxide (NiFeOOH) is recognized as a highly active non-precious metal catalyst in alkaline water electrolysis due to its exceptional catalytic properties. In this work, high valence molybdenum (Mo) is introduced to improve the electronic structure and enhance the electrical conductivity of NiFeOOH for oxygen evolution reaction (OER). The introduction of Mo results in a Mo-doped NiFeOOH catalyst with a significantly reduced overpotential of 205 mV at 10 mA/cm2 and a Tafel slope of 31.7 mV/dec, enabling stable operation for up to 170 h. Both empirical experiment and theory simulations are employed to gain insight into the 3d-electron interactions between molybdenum and nickel (Ni), iron (Fe) in Mo-doped NiFeOOH. The results indicate that Mo-doping enhances the valence states of Ni and Fe, leading to a shift in the d-band center of the bimetallic active sites. This modification affects the transformation of Mo-doped NiFeOOH into the γ-NiFeOOH active phase. This potent combination lends credence to its potential suitability and utility in OER applications.
In recent years, the rapid development of portable/wearable electronics has created an urgent need for the development of flexible energy storage devices. Flexible lithium-ion batteries (FLIBs) have emerged as the most attractive and versatile flexible electronic storage devices available. Carbon nanotubes (CNTs) are hollow-structured tubular nanomaterials with high electrical conductivity, large specific surface area, and excellent mechanical properties. Graphene (G) is to some extent comparable to CNTs, because both have unlimited value in flexible electrodes. Herein, a systematic summary of the application of CNT and G in FLIBs electrodes is presented, including different functional applications and services at different temperatures. Furthermore, the effects of electrode structures, including powder, wire-shaped, and film-shaped structures, on electrochemical properties is highlighted. The assembly structures of the FLIBs consisting of CNT and G-based flexible electrodes to realize different functions, including bendability, stretchability, foldability, self-healing, and self-detecting, are systematically reviewed. The current challenges and development prospects of flexible CNT and G-based flexible electrodes and corresponding FLIBs are discussed.
In modern alkaline batteries, the zinc anode is the performance-limiting and lifetime-limiting electrode, making the choice of zinc powder critical. Due to the various material fabrication processes that are used to manufacture industrial zinc powder, there exists a wide array of possible zinc particle shapes, sizes, and crystallinities. These industrial zinc powders are typically conceived, produced, and tested through trial-and-error processes using historical “rules of thumb.” However, a data-driven approach could more effectively elucidate the optimum combination of zinc particle properties. In this paper, the effect of Zn particle size, shape, and crystallinity on the achievable capacity and corrosion current is investigated. The Zn types are tested in both powder and slurry form. Following the data collection, a factorial-based statistical analysis is performed to determine the most statistically significant variables affecting capacity and corrosion. This information is then used to down-select to a subset of particles that are tested in cylindrical cells with an AA-equivalent geometry. The reported technique can be used to develop actionable principles for battery manufacturers to create cells that are more stable, longer lasting, and have higher energy densities.
Due to the depletion of traditional fossil fuels and the aggravation of related environmental problems, hydrogen energy is gaining more attention all over the world. Solid oxide fuel cell (SOFC) is a promising power generation technology operating on hydrogen with a high efficiency. To further boost the power output of a single cell and thus a single stack, increasing the cell area is an effective route. However, it was recently found that further increasing the effective area of an SOFC single cell with a flat-tubular structure and symmetric double-sided cathodes would result in a lower areal performance. In this work, a multi-physical model is built to study the effect of the effective area on the cell performance. The distribution of different physical fields is systematically analyzed. Optimization of the cell performance is also pursued by systematically tuning the cell operating condition and the current collection setup. An improvement of 42% is revealed by modifying the inlet gas flow rates and by enhancing the current collection. In the future, optimization of cell geometry will be performed to improve the homogeneity of different physical fields and thus to improve the stability of the cell.
In this study, the Lewis doping approach of polyaniline (PANI) was employed to fabricate cobait–nitrogen–carbon (Co–N–C) oxygen electrocatalysts for Zn–air batteries, aiming to enhance the active spots of Co–N–C. This resulting Co–N–C catalysts exhibited well-defined nanofiber networks, and the Brunauer-Emmett-Teller (BET) analysis confirmed their substantial specific surface area. Electrochemical experiments demonstrated that the Co–N–C catalysts achieved the half-wave potential (vs. RHE) of 0.85 V in alkaline medium, overcoming Pt/C and iron–nitrogen–carbon (Fe–N–C) counterparts in extended cycle testing with only a 25 mV change in a half-wave potential after 5000 cycles. Remarkably, the highest power density measured in the zinc (Zn)-air battery reached 227 mW/cm2, a significant improvement over the performance of 101 mW/cm2 of the platinum on activated carbon (Pt/C) catalyst. These findings highlight the advantageous stability enhancement associated with the utilization of Co in the Co–N–C catalysts.
The development of renewable and affordable energy is crucial for building a sustainable society. In this context, establishing a sustainable infrastructure for renewable energy requires the integration of energy storage, specifically use of renewable hydrogen. The hydrogen evolution reaction (HER) of electrochemical water splitting is a promising method for producing green hydrogen. Recently, two-dimensional nanomaterials have shown great promise in promoting the HER in terms of both fundamental research and practical applications due to their high specific surface areas and tunable electronic properties. Among them, molybdenum disulfide (MoS2), a non-noble metal catalyst, has emerged as a promising alternative to replace expensive platinum-based catalysts for the HER because MoS2 has a high inherent activity, low cost, and abundant reserves. At present, greatly improved activity and stability are urgently needed for MoS2 to enable wide deployment of water electrolysis devices. In this regard, efficient strategies for precisely modifying MoS2 are of interest. Herein, the progress made with MoS2 as an HER catalyst is reviewed, with a focus on modification strategies, including phase engineering, morphology design, defect engineering, heteroatom doping, and heterostructure construction. It is believed that these strategies will be helpful in designing and developing high-performance and low-cost MoS2-based catalysts by lowering the charge transfer barrier, increasing the active site density, and optimizing the surface hydrophilicity. In addition, the challenges of MoS2 electrocatalysts and perspectives for future research and development of these catalysts are discussed.
Due to its fascinating and tunable optoelectronic properties, semiconductor nanomaterials are the best choices for multidisciplinary applications. Particularly, the use of semiconductor photocatalysts is one of the promising ways to harness solar energy for useful applications in the field of energy and environment. In recent years, metal oxide-based tailored semiconductor photocatalysts have extensively been used for photocatalytic conversion of carbon dioxide (CO2) into fuels and other useful products utilizing solar energy. This is very significant not only from renewable energy consumption but also from reducing global warming point of view. Such current research activities are promising for a better future of society. The present mini-review is focused on recent developments (2–3 years) in metal oxide semiconductor hybrid photocatalysts-based photo-electrochemical conversion of CO2 into fuels and other useful products. First, general mechanism of photo-electrochemical conversion of CO2 into fuels or other useful products has been discussed. Then, various metal oxide-based emerging hybrid photocatalysts including tailoring of their morphological, compositional, and optoelectronic properties have been discussed with emphasis on their role in enhancing photo-electrochemical efficienty. Afterwards, mechanism of their photo-electrochemical reactions and applications in CO2 conversion into fuels/other useful products have been discussed. Finally, challenges and future prospects have been discussed followed by a summary.
As the next-generation oxy-fuel combustion technology for controlling CO2 emissions, pressurized oxy-fuel combustion (POC) technology can further reduce system energy consumption and improve system efficiency compared with atmospheric oxy-fuel combustion. The oxy-fuel combustion causes high CO2 concentration, which has a series of effects on the combustion reaction process, making the radiation and reaction characteristics different from air-fuel conditions. Under the pressurized oxy-fuel condition, the combustion reaction characteristics are affected by the coupling effect of pressure and atmosphere. The radiation and heat transfer characteristics of the combustion medium are also affected by pressure. In recent years, there have been many studies on POC. This review pays attention to the thermal-science fundamental research. It summarizes several typical POC systems in the world from the perspective of system thermodynamic construction. Moreover, it reviews, in detail, the current research results of POC in terms of heat transfer characteristics (radiant heat transfer and convective heat transfer), combustion characteristics, and pollutant emissions, among which the radiation heat transfer and thermal radiation model are the focus of this paper. Furthermore, it discusses the development and research direction of POC technology. It aims to provide references for scientific research and industrial application of POC technology.
To increase the power generated by solid oxide fuel cells (SOFCs), multiple cells have to be connected into a stack. Nonuniformity of cell performance is a worldwide concern in the practical application of stack, which is known to be unavoidable and caused by manufacturing and operating conditions. However, the effect of such nonuniformity on SOFCs that are connected in parallel has not been discussed in detail so far. This paper provides detailed experimental data on the current distribution within a stack with nonuniform cells in parallel connection, based on the basics of electricity and electrochemistry. Particular phenomena found in such a parallel system are the “self-discharge effect” in standby mode and the “capacity-proportional-load sharing effect” under normal operating conditions. It is believed that the experimental method and results proposed in this paper can be applied to other types of fuel cell or even other energy systems.
Bio-oil from biomass pyrolysis cannot directly substitute traditional fuel due to compositional deficiencies. Catalytic hydrodeoxygenation (HDO) is the critical and efficient step to upgrade crude bio-oil to high-quality bio-jet fuel by lowering the oxygen content and increasing the heating value. However, the hydrocracking reaction tends to reduce the liquid yield and increase the gas yield, causing carbon loss and producing hydrocarbons with a short carbon-chain. To obtain high-yield bio-jet fuel, the elucidation of the conversion process of biomass catalytic HDO is important in providing guidance for metal catalyst design and optimization of reaction conditions. Considering the complexity of crude bio-oil, this review aimed to investigate the catalytic HDO pathways with model compounds that present typical bio-oil components. First, it provided a comprehensive summary of the impact of physical and electronic structures of both noble and non-noble metals that include monometallic and bimetallic supported catalysts on regulating the conversion pathways and resulting product selectivity. The subsequent first principle calculations further corroborated reaction pathways of model compounds in atom-level on different catalyst surfaces with the experiments above and illustrated the favored C–O/C=O scission orders thermodynamically and kinetically. Then, it discussed hydrogenation effects of different H-donors (such as hydrogen and methane) and catalysts deactivation for economical and industrial consideration. Based on the descriptions above and recent researches, it also elaborated on catalytic HDO of biomass and bio-oil with multi-functional catalysts. Finally, it presented the challenges and future prospective of biomass catalytic HDO.
To achieve effective intraday dispatch of photovoltaic (PV) power generation systems, a reliable ultra-short-term power generation forecasting model is required. Based on a gradient boosting strategy and a dendritic network, this paper proposes a novel ensemble prediction model, named gradient boosting dendritic network (GBDD) model which can reduce the forecast error by learning the relationship between forecast residuals and meteorological factors during the training of sub-models by means of a greedy function approximation. Unlike other machine learning models, the GBDD proposed is able to make fuller use of all meteorological factor data and has a good model interpretation. In addition, based on the structure of GBDD, this paper proposes a strategy that can improve the prediction performance of other types of prediction models. The GBDD is trained by analyzing the relationship between prediction errors and meteorological factors for compensating the prediction results of other prediction models. The experimental results show that the GBDD proposed has the benefit of achieving a higher PV power prediction accuracy for PV power generation and can be used to improve the prediction performance of other prediction models.
Polyimide (PI) has emerged as a promising organic photocatalyst owing to its distinct advantages of high visible-light response, facile synthesis, molecularly tunable donor-acceptor structure, and excellent physicochemical stability. However, the synthesis of high-quality PI photoelectrode remains a challenge, and photoelectrochemical (PEC) water splitting for PI has been less studied. Herein, the synthesis of uniform PI photoelectrode films via a simple spin-coating method was reported, and their PEC properties were investigated using melamine as donor and various anhydrides as acceptors. The influence of the conjugate size of aromatic unit (phenyl, biphenyl, naphthalene, perylene) of electron acceptor on PEC performance were studied, where naphthalene-based PI photoelectrode exhibited the highest photocurrent response. This is resulted from the unification of wide-range light absorption, efficient charge separation and transport, and strong photooxidation capacity. This paper expands the material library of polymer films for PEC applications and contributes to the rational design of efficient polymer photoelectrodes.
This paper proposes a new power generating system that combines wind power (WP), photovoltaic (PV), trough concentrating solar power (CSP) with a supercritical carbon dioxide (S-CO2) Brayton power cycle, a thermal energy storage (TES), and an electric heater (EH) subsystem. The wind power/photovoltaic/concentrating solar power (WP−PV−CSP) with the S-CO2 Brayton cycle system is powered by renewable energy. Then, it constructs a bi-level capacity-operation collaborative optimization model and proposes a non-dominated sorting genetic algorithm-II (NSGA-II) nested linear programming (LP) algorithm to solve this optimization problem, aiming to obtain a set of optimal capacity configurations that balance carbon emissions, economics, and operation scheduling. Afterwards, using Zhangbei area, a place in China which has significant wind and solar energy resources as a practical application case, it utilizes a bi-level optimization model to improve the capacity and annual load scheduling of the system. Finally, it establishes three reference systems to compare the annual operating characteristics of the WP−PV−CSP (S-CO2) system, highlighting the benefits of adopting the S-CO2 Brayton cycle and equipping the system with EH. After capacity-operation collaborative optimization, the levelized cost of energy (LCOE) and carbon emissions of the WP−PV−CSP (S-CO2) system are decreased by 3.43% and 92.13%, respectively, compared to the reference system without optimization.
Utilizing plasmonic effects to assist electrochemical reactions exhibits a huge potential in tuning the reaction activities and product selectivity, which is most appealing especially in chemical reactions with multiple products, such as CO2 reduction reaction (CO2RR). However, a comprehensive review of the development and the underlying mechanisms in plasmon-assisted electrocatalytic CO2RR remains few and far between. Herein, the fundamentals of localized surface plasmonic resonance (LSPR) excitation and the properties of typical plasmonic metals (including Au, Ag, and Cu) are retrospected. Subsequently, the potential mechanisms of plasmonic effects (such as hot carrier effects and photothermal effects) on the reaction performance in the field of plasmon-assisted electrocatalytic CO2RR are summarized, which provides directions for the future development of this field. It is concluded that plasmonic catalysts exhibit potential capabilities in enhancing CO2RR while more in situ techniques are essential to further clarify the inner mechanisms.