The Fe-Mn bimetallic catalyst is a potential candidate for the conversion of CO₂ into value-added chemicals. The interaction between the two metals plays a significant role in determining the catalytic performance, however which remains controversial. In this study, we aim to investigate the impact of tuning the proximity of Fe-Mn bimetallic catalysts with similar nanoparticle size. And its effect on the physicochemical properties of the catalysts and corresponding performance were investigated. It was found that closer Fe-Mn proximity resulted in enhanced CO₂ hydrogenation activity and inhibited CH₄ formation. The physiochemical properties of prepared catalysts were characterized using X-ray diffraction, H₂ temperature programmed reduction, and X-ray photoelectron spectroscopy, revealing that a closer Fe-Mn distance promoted electron transfer from Mn to Fe, thereby facilitating Fe carburization. The adsorption behavior of CO₂ and the identification of reaction intermediates were analyzed using CO₂-temperature programed desorption and in situ Fourier transform infrared spectroscopy, confirming the intimate Fe-Mn sites contributed to CO₂ adsorption and the formation of HCOO* species, ultimately leading to increased CO₂ conversion and hydrocarbon production. The discovery of a synergistic effect at the intimate Fe-Mn sites in this study provides valuable insights into the relationship between active sites and promoters.

Unspecific peroxygenases exhibit high activity for the selective oxyfunctionalization of inert C(sp³)–H bonds using only H₂O₂ as a clean oxidant, while also exhibiting sensitivity to H₂O₂ concentration. CdS-based semiconductors are promising for the photosynthesis of H₂O₂ owing to their adequately negative potential for oxygen reduction reaction via a proton-coupled electron transfer process, however, they suffer from fast H₂O₂ decomposition on the surface of pristine CdS. Therefore, [Cp*Rh(bpy)H₂O]²⁺, a highly selective proton-coupled electron transfer catalyst, was anchored onto a supramolecular polymer-grafted CdS nanoflower to construct an efficient integrated photocatalyst for generating H₂O₂, mitigating the surface issue of pristine CdS, increasing light absorption, accelerating photonic carrier separation, and enhancing oxygen reduction reaction selectivity to H₂O₂. This photocatalyst promoted the light driven H₂O₂ generation rate up to 1345 μmol·L^–1·g^–1·h^–1, which was 2.4 times that of pristine CdS. The constructed heterojunction photocatalyst could supply H₂O₂ in situ for nonspecific peroxygenases to catalyze the C–H oxyfunctionalization of ethylbenzene, achieving a yield of 81% and an ee value of 99% under optimum conditions. A wide range of substrates were converted to the corresponding chiral alcohols using this photo-enzyme catalytic system, achieving the corresponding chiral alcohols in good yield (51%–88%) and excellent enantioselectivity (90%–99% ee).

Higher alcohol synthesis directly from syngas is highly desirable as one of the efficient non-petroleum energy conversion routes. Co⁰–CoO catalysts showed great potential for this reaction, but the alcohol selectivity still needs to be improved and the crystal structure effect of CoO on catalytic behaviors lacks investigation. Here, a series of tetrahedrally coordinated CoO polymorphs were prepared by a thermal decomposition method, which consisted of wurtzite CoO and zinc blende CoO with varied contents. After diluting with SiO₂, the catalyst showed excellent performance for higher alcohol synthesis with ROH selectivity of 45.8% and higher alcohol distribution of 84.1 wt % under the CO conversion of 38.0%. With increasing the content of wurtzite CoO, the Co⁰/Co²⁺ ratio gradually increased in the spent catalysts, while the proportion of highly active hexagonal close packed cobalt in Co⁰ decreased, leading to first decreased then increased CO conversion. Moreover, the higher content of zinc blende CoO in fresh catalyst facilitated the retention of more Co²⁺ sites in spent catalysts, promoting the ROH selectivity but slightly decreasing the distribution of higher alcohols. The catalyst with 40% wurtzite CoO obtained the optimal performance with a space time yield toward higher alcohols of 7.9 mmol·g_cat^–1·h^–1.

The oxidative condensation between renewable furfural and fatty alcohols is a crucial avenue for producing high-quality liquid fuels and valuable furan derivatives. The selectivity control in this reaction process remains a significant challenge. Herein, we report the strategy of confining well dispersed gold species within ZSM-5 structure to construct highly active Au@ZSM-5 zeolite catalysts for the oxidative condensation of furfural. Characterization results and spectroscopy analyses demonstrate the efficient encapsulation of isolated and cationic Au clusters in zeolite structure. Au@ZSM-5(K) catalyst shows remarkable performance with 69.7% furfural conversion and 90.2% furan-2-acrolein selectivity as well as good recycle stability. It is revealed that the microstructure of ZSM-5 zeolite can significantly promote oxidative condensation activity through confinement effects. This work presents an explicit example of constructing zeolite encaged noble metal catalysts toward targeted chemical transformations.

Epoxidation of propylene to propylene oxide (PO) with hydrogen peroxide (HPPO) is an environmentally friendly and cost-efficient process in which titanosilicates are used as catalysts. Ti-MWW is a potential industrial catalyst for this process, which involves the addition of HPPO to PO. The silanol groups generated during secondary crystallization unavoidably result in ring-opening of PO and inefficient decomposition of HPPO, which diminish the PO selectivity and the lifespan of Ti-MWW. To address this issue, we conducted post-treatment modifications of the structured Bf-Ti-MWW catalyst with potassium fluoride aqueous solutions. By quenching the silanol groups with potassium fluoride and implanting electron-withdrawing fluoride groups into the Ti-MWW framework, both the catalytic activity and HPPO utilization efficiency were increased. Moreover, the ring opening reaction of PO was prohibited. In a continuous fixed-bed liquid-phase propylene epoxidation reaction, the KF-treated structured Ti-MWW catalyst displayed an exceptionally long lifespan of 2700 h, with a PO yield of 590 g·kg⁻¹·h⁻¹.

With regard to green chemistry and sustainable development, the fixation of CO₂ into epoxides to form cyclic carbonates is an attractive and promising pathway for CO₂ utilization. Metal oxides, renowned as promising eco-friendly catalysts for industrial production, are often undervalued in terms of their impact on the CO₂ addition reaction. In this work, we successfully developed ZnO nanoplates with (002) surfaces and ZnO nanorods with (100) surfaces via morphology-oriented regulation to explore the effect of crystal faces on CO₂ cycloaddition. The quantitative data obtained from electron paramagnetic resonance spectroscopy indicated that the concentration of oxygen vacancies on the ZnO nanoplate surfaces was more than twice that on the ZnO nanorod surfaces. Density functional theory calculations suggested that the (002) surfaces have lower adsorption energies for CO₂ and epichlorohydrin than the (100) surfaces. As a result, the yield of cyclochloropropene carbonate on the ZnO nanoplates (64.7%) was much greater than that on the ZnO nanorods (42.3%). Further evaluation of the reused catalysts revealed that the decrease in the oxygen vacancy concentration was the primary factor contributing to the decrease in catalytic performance. Based on these findings, a possible catalytic mechanism for CO₂ cycloaddition with epichlorohydrin was proposed. This work provides a new idea for the controllable preparation of high-performance ZnO catalysts for the synthesis of cyclic carbonates from CO₂ and epoxides.

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.

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.

Surface engineering and Cu valence regulation are essential factors in improving the C₂ selectivity during the electrochemical reduction of CO₂. Herein, we present a sea urchin-like CuO/Cu₂O catalyst derived from rhombic dodecahedra Cu₂O through one-step oxidation/etching method where the mixed Cu⁺/Cu⁰ states are formed via in situ reduction during electrocatalysis. The combined effects of the morphology and the mixed Cu⁺/Cu⁰ states on C–C coupling are evaluated by the Faradaic efficiency of C₂ and the C₂/C₁ ratio obtained in an H-cell. R-CuO/Cu₂O exhibited 49.5% Faradaic efficiency of C₂ with a C₂/C₁ ratio of 3.1 at −1.4 V vs. reversible hydrogen electrode, which are 1.5 and 3.2 times higher than those of R-Cu₂O, respectively. Using a flow-cell, 68.0% Faradaic efficiency of C₂ is achieved at a current density of 500 mA·cm⁻². The formation of the mixed Cu⁺/Cu⁰ states was confirmed by in situ Raman spectra. Additionally, the sea urchin-like structure provides more active sites and enables faster electron transfer. As a result, the excellent C₂ production on R-CuO/Cu₂O is primarily attributed to the synergistic effects of the sea urchin-like structure and the stable mixed Cu⁺/Cu⁰ states. Therefore, this work presents an integrated strategy for developing Cu-based electrocatalysts for C₂ production through electrochemical CO₂ reduction.