Construction of porous Cu/CeO2 catalyst with abundant interfacial sites for effective methanol steam reforming.

Methanol is a promising hydrogen carrier for fuel cell vehicles (FCVs) via methanol steam reforming (MSR) reaction. Ceria supported copper catalyst has attracted extensive attentions due to the extraordinary oxygen storage capacity and abundant oxygen vacancies. Herein, we developed a colloidal solution combustion (CSC) method to synthesize a porous Cu/CeO2(CSC) catalyst. Compared with Cu/CeO2 catalysts prepared by other methods, the Cu/CeO2(CSC) catalyst possesses highly dispersed copper species and abundant Cu+-Ov-Ce3+ sites at the copper-ceria interface, contributing to methanol conversion of 66.3 %, CO2 selectivity of 99.2 %, and outstanding hydrogen production rate of 490 mmol gcat-1 h-1 under 250 °C. The linear correlation between TOF values and Cu+-Ov-Ce3+ sites amount indicates the vital role of Cu+-Ov-Ce3+ sites in MSR reaction, presenting efficient ability in activation of water. Subsequently, a deep understanding of CSC method is further presented. In addition to serving as a hard template, the colloidal silica also acts as disperser between nanoparticles, enhancing the copper-ceria interactions and facilitating the generation of Cu+-Ov-Ce3+ sites. This study offers an alternative approach to synthesize highly dispersed supported copper catalysts.

Insights into the roles of nitrogen and phosphorus co-doping for efficient methanol electrooxidation.

Anchoring Pt onto multi-heteroatom doped carbon materials has been recognized as an effective approach to improve the performance of electrocatalytic methanol oxidation. However, distinct contributions and specific behavior mechanisms of different heteroatoms, notably N and P, the specific behavior mechanisms in synergistically promoting Pt NPs remain elusive. In this work, we construct 1D N and P co-doped carbon nanotube (N, P-CNTs) supports with abundant defect anchors for Pt. The as-prepared Pt/N, P-CNTs exhibit outstanding activity and exceptional stability in methanol oxidation reaction (MOR), achieving high mass activity up to 6481.3 mA mg-1Pt. Moreover, they can retain 90.5 % of their initial current density even after 800 cycles tests. Detailed characterizations and theoretical calculations indicate that the robust strong metal-support interactions (SMSI) effect caused by N doping within the unique N and P co-doped coordination structure controllably regulate the coordination environment of Pt, reduce the d-band center of Pt, thus promoting the adsorption and decomposition of CH3OH. However, P doping weakens the adsorption strength of CO on the Pt active site by sacrificing partial electron transfer, accelerating the oxidative conversion of the CO-like poisoning species (COads). Significantly, the synergistic mechanism of N and P species on the modification of Pt's electronic structure and its subsequent impact on the electrocatalytic methanol oxidation behaviors on the Pt surface was thoroughly elucidated, providing a constructive route for designing robust MOR electrocatalysts with high MOR activity and durability.

Trimetallic Ni-CuCoN0.6 Ohmic junction for the enhanced oxidation of methanol and urea.

Methanol oxidation reaction (MOR) and urea oxidation reaction (UOR) can be utilized as effective alternatives to the anodic oxygen evolution reaction (OER) in overall water-splitting. Nevertheless, the development of cost-effective, highly efficient and durable electrocatalysts for MOR and UOR remains a significant challenge. Herein, the Ohmic junction (Ni-CuCoN0.6@CC) comprising CuCoN0.6 nanosheets and Ni nanoparticles anchored on carbon cloth (CC) was successfully synthesized via a two-step hydrothermal process followed by pyrolysis. The Ni-CuCoN0.6@CC demonstrates exceptional performance in both MOR (1.334 V@10 mA cm-2) and UOR (1.335 V@10 mA cm-2), coupled with outstanding durability, maintaining 88.70 % current density for MOR and 88.92 % for UOR after a rigorous 50-h stability test. Furthermore, the Ni-CuCoN0.6@CC demonstrates a high selectivity for oxidizing methanol to formic acid, achieving Faraday efficiencies exceeding 90 % at various current densities in the context of MOR. The outstanding performance of Ni-CuCoN0.6@CC in terms of MOR and UOR either surpasses or closely approaches the levels reported in previous literature, primarily due to the synergistic effect resulting from the Ohmic junction: in this system, Ni serves as the principal active component, Co augments catalytic activity and diminishes onset potential, while Cu enhances long-term durability. Moreover, CuCoN0.6 nanosheets effectively modulate electronic structure and optimize the morphology of Ni, leading to the exposure of numerous defects that provide a wealth of active sites for the reaction. Additionally, the exceptional hydrophilic and aerophobic surface promotes enhanced mass transfer. Density functional theory (DFT) calculations show that Ni-CuCoN0.6@CC enhances reactant adsorption and product desorption, reducing energy barriers and expediting MOR and UOR kinetics.

Modulating d-Orbital electronic configuration via metal-metal oxide interactions for boosting electrocatalytic methanol oxidation.

Coordinating the interfacial interaction between Pt-based nanoparticles (NPs) and supports is a significant strategy for the modulation of d-orbital electronic configuration and the adsorption behaviors of intermediates, which is of critical importance for boosting electrocatalytic performance. Herein, we demonstrated a specific synergy effect between the ordered PtFe intermetallic and neighboring oxygen vacancies (Ov), which provides an "ensemble reaction pool" to balance the barriers of both the activity, stability, and CO poisoning issues for the methanol oxidation reaction (MOR). In our proposed "ensemble reaction pool", the deprotonation of methanol occurs on the Pt site to form the intermediate *CO, where the strain derived from the PtFe intermetallic could alter the d-orbital electronic configuration of Pt, intrinsically weakening the *CO adsorption energy, and Ov in CeO2 promote hydroxyl species (*OH) adsorption, which will react with *CO, facilitating the dissociative adsorption of *CO, thus cooperatively enhancing the performance of MOR. The X-ray absorption fine structure (XAFS) analyses reveal the electron transfer in CeO2 and then convert Ce4+ to Ce3+. The density functional theory (DFT) calculations revealed that introducing Fe induces strain could modify the d-band center of Pt, and thus lower the energy barrier of the potential-determining step. Meanwhile, the introduction of CeO2 can favor the *OH adsorption, speeding up the oxidation and removal of *CO blocked at the Pt site. Furthermore, the determined atomic arrangement and surface composition of PtFe intermetallic further guarantee the stability of MOR by suppressing less-noble metal into the electrolyte.

Theoretical design and synthesis of Co30Ni60/CC for high selective methanol oxidation assisted energy-saving hydrogen production.

The integration of methanol oxidation reaction (MOR) with hydrogen evolution reaction (HER) represents an advanced approach to hydrogen production technology. Nonetheless, the rational design and synthesis of bifunctional catalysts for both MOR and HER with exceptional activity, stability and selectivity present formidable challenges. In this work, firstly, density functional theory (DFT) was utilized to design and evaluate material models with high performance for both MOR and HER. Secondly, guided by DFT, Co30Ni60/CC (CC, carbon cloth) composites with a leaf-like nanosheet structure were successfully fabricated via electrodeposition. In the MOR process, Ni acts as the predominant active center, while Co amplifies the electrochemically active surface area (ECSA) and enhances the selectivity of methanol oxidation. Conversely, in the HER process, Co serves as the primary active center, with Ni augmenting the charge transfer rate. The electrochemical results demonstrate that Co30Ni60/CC exhibits exceptional performance in both MOR and HER at a current density (j) of 10 mA cm-2, with peak potentials of 1.323 V and -95 mV, respectively. Additionally, it shows remarkable selectivity for the oxidiation of methanol to high value-added formic acid. Thirdly, following a 100 h chronopotentiometry (CP) test, the required potential demonstrates an increase of 4.9 % (MOR) and 8.1 % (HER), signifying the superior stability of Co30Ni60/CC compared to those reported in the literature. The exceptional performance of Co30Ni60/CC can be primarily attributed to that the leaf-like nanosheets structure not only exposes a plethora of active sites but also facilitates electrolyte diffusion, the monolithic structure prepared by electrodeposition enhances its stability, and the transfer of electrons from Co to Ni regulates its electronic structure, as corroborated by X-ray photoelectron spectroscopy (XPS) and density of states (DOS) analyses. Finally, at the same j, the voltage required by the Co30Ni60/CC||Co30Ni60/CC electrolytic cell, powered by an electrochemical workstation, is 198 mV lower than that required for alkaline water-splitting. Meanwhile, at higher j (100 mA cm-2), the electrolytic cell exhibits sustained and stable operation for 150 h, enabling high-efficiency hydrogen production and the synthesis of high value-added formic acid.

De novo biosynthesis of ß-Arbutin in Komagataella phaffii based on metabolic engineering strategies.

BACKGROUND: ß-Arbutin, found in the leaves of bearberry, stands out as one of the globally acknowledged eco-friendly whitening additives in recent years. However, the natural abundance of ß-Arbutin is low, and the cost-effectiveness of using chemical synthesis or plant extraction methods is low, which cannot meet the requirements. While modifying the ß-Arbutin synthesis pathway of existing strains is a viable option, it is hindered by the limited synthesis capacity of these strains, which hinders further development and application. RESULTS: In this study, we established a biosynthetic pathway in Komagataella phaffii for ß-Arbutin production with a titer of 1.58 g/L. Through diverse metabolic strategies, including fusion protein construction, enhancing shikimate pathway flux, and augmenting precursor supplies (PEP, E4P, and UDPG), we significantly increased ß-Arbutin titer to 4.32 g/L. Further optimization of methanol concentration in shake flasks led to a titer of 6.32 g/L titer after 120 h of fermentation, representing a fourfold increase over the initial titer. In fed-batch fermentation, strain UA3-10 set a record with the highest production to date, reaching 128.6 g/L in a 5 L fermenter. CONCLUSIONS: This is the highest yield in the fermentation tank level of using microbial cell factories for de novo synthesis of ß-Arbutin. Applying combinatorial engineering strategies has significantly improved the ß-Arbutin yield in K. phaffii and is a promising approach for synthesizing functional products using a microbial cell factory. This study not only advances low-cost fermentation-based production of ß-Arbutin but also establishes K. phaffii as a promising chassis cell for synthesizing other aromatic amino acid metabolites.

Active Sites for CO2 Hydrogenation to Methanol: Mechanistic Insights and Reaction Control.

Catalytic CO2 conversion to methanol is a promising way to extenuate the adverse effects of CO2 emission, global warming and energy shortage. Understanding the fundamental features of CO2 activation and hydrogenation at the molecular level is essential for carbon utilization and sustainable chemical production in the current climate crisis. This review explores the recent advances in understanding the design of catalysts with desired active sites, including single-atom, dual-atom, interface, defects/vacancies and promoters/dopants. We focused on the design of various catalytic systems to enhance their catalytic performances by stabilizing active metal in a catalyst, identifying the unique structure of active species, and engineering coordination environments of active sites. Mechanistic insights provided by advanced operando and in situ spectroscopies were also discussed. Moreover, the review highlights the key factors affecting active sites and reaction mechanisms, such as local environments, oxidation states, and metal-support interactions. By integrating recent advancements and relating knowledge gaps this review aims to endow an inclusive overview of the field and guide future research toward more efficient and selective catalysts for CO2 hydrogenation to methanol.

Enhanced Methanol Electrooxidation and Supercapacitive Performance via Compositional Engineering of Colloidal Ni-Co Alloying Nanoparticles.

Among renewable energy technologies, particular attention is paid to electrochemically transforming methanol into valuable formate and storing energy into supercapacitors. In this study, we detailed a simple colloidal-based protocol for synthesizing a series of alloy nanoparticles with tuned Ni/Co atomic ratios, thereby optimizing their electrochemical performance. With the addition of 1 M methanol in 1 M KOH, the optimized composition was able to electrochemically produce formate at 0.149 mmol cm-2 h-1 with a Faradaic efficiency up to 95.1% at 0.6 V versus Hg/HgO within a 22-hour testing period. In 1 M KOH solution without methanol, the supercapacitive performance was achieved at a specific capacitance of over 1500 F g-1, and outstanding cycling stability with only approximately 20% decay after continuous 10000 charging-discharging cycles. These results underscore that the prepared Ni-Co alloy nanoparticles serve as multi-functional electrodes for electrochemical energy conversion and storage, particularly in the MOR and supercapacitors applications.

Highly Dispersed ZnO Sites in a ZnO/ZrO2 Catalyst Promote Carbon Dioxide-to-Methanol Conversion.

ZnO/ZrO2 catalysts have shown better activity in the CO2 hydrogenation to methanol compared with single component counterparts, but the interaction between ZnO and ZrO2 is still poorly understood. In particular, the effect of the ZrO2 support phase (tetragonal vs. monoclinic) was not systematically explored. Here, we have synthesized ZnO/ZrO2 catalysts supported on tetragonal ZrO2 (ZnO/ZrO2-t) and monoclinic ZrO2 (ZnO/ZrO2-m), which resulted in the formation of different ZnOx species, consisting of sub-nanometer ZnO moieties and large-sized ZnO particles, respectively. ZnO/ZrO2-t exhibited a higher methanol selectivity (81 vs. 39%) and methanol yield (1.25 vs. 0.67 mmol g-1 h-1) compared with ZnO/ZrO2-m. The difference in performance was attributed to the redox state and degree of dispersion of Zn, based on spectroscopy and microscopy results. ZnO/ZrO2-t had a high density of ZnOx-ZrOy sites, which favored the formation of active HCOO* species and enhanced the yield and selectivity of methanol along the formate pathway. Such ZnO clusters were further dispersed on ZrO2-t during catalysis, while larger ZnO particles on ZnO/ZrO2-m remained stable throughout the reaction. This study shows that the phase of ZrO2 supports can be used to control the dispersion of ZnO and the catalyst surface chemistry, and lead to enhanced catalytic performance.

Emerging ZnO Semiconductors for Photocatalytic CO2 Reduction to Methanol.

Carbon recycling is poised to emerge as a prominent trend for mitigating severe climate change and meeting the rising demand for energy. Converting carbon dioxide (CO2) into green energy and valuable feedstocks through photocatalytic CO2 reduction (PCCR) offers a promising solution to global warming and energy needs. Among all semiconductors, zinc oxide (ZnO) has garnered considerable interest due to its ecofriendly nature, biocompatibility, abundance, exceptional semiconducting and optical properties, cost-effectiveness, easy synthesis, and durability. This review thoroughly discusses recent advances in mechanistic insights, fundamental principles, experimental parameters, and modulation of ZnO catalysts for direct PCCR to C1 products (methanol). Various ZnO modification techniques are explored, including atomic size regulation, synthesis strategies, morphology manipulation, doping with cocatalysts, defect engineering, incorporation of plasmonic metals, and single atom modulation to boost its photocatalytic performance. Additionally, the review highlights the importance of photoreactor design, reactor types, geometries, operating modes, and phases. Future research endeavors should prioritize the development of cost-effective catalyst immobilization methods for solid-liquid separation and catalyst recycling, while emphasizing the use of abundant and non-toxic materials to ensure environmental sustainability and economic viability. Finally, the review outlines key challenges and proposes novel directions for further enhancing ZnO-based photocatalytic CO2 conversion processes.

Simultaneously Promoted Water Resistance and CO2 Selectivity in Methanol Oxidation Over Pd/CoOOH: Synergy of Co-OH and the Pd-Olatt-Co Interface.

Catalytic purification of industrial oxygenated volatile organic compounds (OVOCs) is hindered by the presence of water vapor that attacks the active sites of conventional noble metal-based catalysts and the insufficient mineralization that leads to the generation of hazardous intermediates. Developing catalysts simultaneously with excellent water resistance and a high intermediate suppression ability is still a great challenge. Herein, we proposed a simple strategy to synthesize a Pd/CoOOH catalyst that contains abundant hydroxyl groups and lattice oxygen species, over which a negligible effect was observed on CH3OH conversion with 3 vol % water vapor, while a remarkable conversion reduction of 24% was observed over Pd/Co3O4. Moreover, the low-temperature CO2 selectivity over Pd/CoOOH is significantly enhanced in comparison with Pd/Co(OH)2. The high concentration of surface hydroxyl groups on Pd/CoOOH enhances the water resistance owing to the accelerated activation of H2O to generate Co-OH, which replaces the consumed hydroxyl and facilitates the quick dissociation of surface H2O through timely desorption. Additionally, the presence of Pd-Olatt-Co promotes electron transport from Co to Pd, leading to improved metal-support interactions and weakened metal-O bonds. This in turn enhances the catalyst's capacity to efficaciously convert intermediates. This study sheds new insights into designing multifunctional catalytic platforms for efficient industrial OVOC purification as well as other heterogeneous oxidation reactions.

The role of microwave radiation in extractive desulfurization of real diesel fuel for green environment: an experimental and computational investigation.

The process of removing sulfur compounds and aromatic compounds to produce clean fuel is an important and effective contribution to the processes of mitigating and adapting to climate change. In contrast, it is necessary to find an innovative way to remove sulfur and carcinogenic aromatic compounds because clean, low-sulfur diesel is commonly used in all countries of the world at the present time. Therefore, in this work, we have studied the effect of the microwave radiation power and the irradiation time with the use of more than one type of organic solvent; methanol, acetonitrile and ethyl acetoacetate; as an extractant and solvent to feed ratio impact on the removal of sulfur and aromatic compounds of a real diesel fuel feed which has 450 ppm sulfur content and 16 wt% aromatic Content. The results showed that the best solvent used during this work was ethyl acetoacetate. According to the results, high sulfur removal (≈ 92%) was accomplished with microwave-assisted extractive desulfurization technique under the following ideal conditions: the irradiation time is 7 min, the solvent feed ratio is 3:1 and the microwave intensity is 180 W. To reveal the mechanism of microwave-assisted extractive desulfurization via different organic solvents, a theoretical study including structural examination and interaction energy analysis on the interaction between dibenzothiophene (DBT) or dimethyl dibenzothiophene (DMDBT) and the different organic solvents was also conducted.

Modification d x 2 - y 2 ${{d}_{{{x}2} - {{y}2}}}$ Orbital Electronic States in Nickel-Based Hydroxides Via Cobalt/Iron Co-Doping for High-Efficiency Methanol Electrooxidation.

The nickel hydroxide-based (Ni(OH)2) methanol-to-formate electrooxidation reaction (MOR) performance is greatly related to the d x 2 - y 2 ${{d}_{{{x}^2} - {{y}^2}}}$ orbital electronic states. Hence, optimizing the d x 2 - y 2 ${{d}_{{{x}^2} - {{y}^2}}}$ orbital electronic states to achieve enhanced MOR activities are highly desired. Here, cobalt (Co) and iron (Fe) doping are used to modify the d x 2 - y 2 ${{d}_{{{x}^2} - {{y}^2}}}$ orbital electronic states. Although both dopants can broaden the d x 2 - y 2 ${{d}_{{{x}^2} - {{y}^2}}}$ orbital; however, Co doping leads to an elevation in the energy level of d x 2 - y 2 ${{d}_{{{x}^2} - {{y}^2}}}$ highest occupied crystal orbital (HOCO), whereas Fe doping results in its reduction. Such a discrepancy in the regulation of d x 2 - y 2 ${{d}_{{{x}^2} - {{y}^2}}}$ orbital electronic states stems from the disparate partial electron transfer mechanisms amongst these transition metal ions, which possess distinct energy level and occupancy of d orbitals. Motivated by this finding, the NiCoFe hydroxide is prepared and exhibited an excellent MOR performance. The results showed that the Co dopants effectively suppress the partial electron transfer from Ni to Fe, combined with the d x 2 - y 2 ${{d}_{{{x}^2} - {{y}^2}}}$ orbital broadening induced by NiO6 octahedra distortion, endowing NiCoFe hydroxide with high d x 2 - y 2 ${{d}_{{{x}^2} - {{y}^2}}}$ HOCO and broad d x 2 - y 2 ${{d}_{{{x}^2} - {{y}^2}}}$ orbital. It is believed that the work gives an in-depth understanding on d x 2 - y 2 ${{d}_{{{x}^2} - {{y}^2}}}$ orbital electronic states regulation in Ni(OH)2, which is beneficial for designing Ni(OH)2-based catalysts with high MOR performance.

The importance of both catalyst and process design in unlocking sustainable carbon feedstocks through syngas.

As part of its move towards net zero, the chemical industry, over time, will transition away from fossil-based chemical feedstocks towards more sustainable, 'green' carbon-biomass, recycled waste and captured carbon dioxide. One gateway to transforming these feedstocks into the vital chemicals and fuels society relies on is via synthesis gas or 'syngas'-a gaseous mixture of chemical building blocks (H2, CO and CO2). While today the majority of syngas is produced via steam reforming of natural gas, commercially available technologies are enabling syngas production and transformation from sustainable feedstocks. The optimization of sustainable syngas technologies would not be possible without the integrated development of both catalyst and process technology and the associated skills in chemistry and chemical engineering. This paper covers three example technologies that are unlocking the role of syngas as a gateway to sustainable fuels and chemicals and highlights the innovative developments in catalyst and process design that have enabled their optimization and commercialization. This article is part of the discussion meeting issue 'Green carbon for the chemical industry of the future'.

Optimizing trigeneration energy systems: Biogas-centric methanol production via direct CO2 hydrogenation with advanced integration of PEM electrolyzer and LNG cold technology.

Biogas, a sustainable alternative to fossil fuels, addresses issues of non-renewability and accessibility. Its structural similarity to fossil fuels makes it a potent option for energy systems. With this in mind, this paper discusses a novel trigeneration system that utilizes biogas and Liquefied natural gas cooling to produce methanol, electricity, cold water, hot water, oxygen, and natural gas. The system integrates various components such as a biogas burner, Kalina cycle, organic Rankine cycle, liquefied natural gas liquid gasification cycle, proton exchange membrane electrolyzer, and methanol synthesis unit. Simulation via Aspen HYSYS software includes an analysis of energy, exergy, economic, and environmental aspects. Efficiency assessment in single generation, cogeneration, trigeneration, and chemical trigeneration modes concludes chemical trigeneration as most efficient, with the proton exchange membrane electrolyzer being the most efficient subsystem. Key variables like Kalina cycle evaporator temperature, gas flow rate to the methanol reactor, and organic Rankine cycle working fluid pressure are assessed. Predictions on thermodynamic, environmental, and economic behaviors, along with their fluctuations, are made. Using a thermoeconomic approach, the economic analysis determines an exergy unit cost of 59.79 $/GJ and a total cost rate of 2764 $/h. Overall, this work presents a novel and efficient chemical trigeneration system that utilizes biogas and LNG cooling to produce multiple products.

Zinc Vaporization Induced Formation of Desired Ni Nanoparticles Coated with Ultrathin Carbon Shells for Efficient Electrocatalytic H2 Production Coupling with Methanol Upgrading.

The integration of the hydrogen evolution reaction (HER) with the methanol oxidation reaction (MOR) has been demonstrated to be a viable strategy for the energy-saving generation of H2 and value-added formate, which relies primarily on highly active and cost-effective bifunctional electrocatalysts. Herein, an efficient electrocatalyst consisting of controllable Ni nanoparticles (NPs) coated with ultrathin graphitic carbon shells was obtained by the pyrolysis of a Ni-Zn metal-organic framework. Intriguingly, we found that zinc vaporization not only resulted in the relatively small Ni NPs but also ultrathin carbon shells (≤3 layers). The density functional theory simulations confirmed that these ultrathin carbon shells significantly influenced electrocatalytic activity by facilitating electron transfer from the Ni core to the carbon shell. The optimized Ni1(Zn)@C demonstrated high catalytic activity for both HER and MOR, and only a low potential of 97 mV at 10 mA cm-2 was required for HER and 1.48 V at 30 mA cm-2 for MOR. In a two-electrode electrocatalytic cell measurement, a cell voltage of 1.63 V was observed at 10 mA cm-2 in the presence of methanol, 240 mV lower than that without methanol.

Designing TiO2 Nanotubular Arrays with Au-CoOx Core-Shell Nanoparticles for Enhanced Photoelectrochemical Methanol and Lignin Oxidation.

One-dimensional (1D) ordered TiO2 nanotubes exhibit exceptional charge transfer capabilities, making them suitable candidates for constructing visible-light-active photoanodes in selective PEC oxidation reactions. Herein, we employed a facile and easily scalable electrochemical method to fabricate Au-CoOx-deposited ordered TiO2 nanotubular array photoanodes. The improved visible light absorption capacity of TiO2-Au-CoOx, with unhampered 1D channels and the controlled integration of Au between TiO2 and CoOx, along with their synergistic interaction, have been identified as the most promising strategy for enhanced PEC performance, as evidenced by an IPCE of 3.7% at 450 nm. Furthermore, the robust interfacial charge transfer pathway from CoOx to the TiO2 surface via the Au mediator promotes the migration of photogenerated electrons and enables the accumulation of holes on the surface of CoOx. These holes are then efficiently utilized by oxidants such as methanol or lignin to generate value-added products, highlighting the potential of this system for advanced PEC applications.

Stable Cu/Cu2O/CuN3@NC Catalysts for Aqueous Phase Reforming of Methanol.

Aqueous-phase reforming of methanol represents a promising avenue for hydrogen (H2) production. However, developing highly efficient and low-cost nonprecious catalysts remains challenging. Here, we report the synthesis of Cu-based catalysts with Cu, Cu2O, and CuN3 nanoparticles anchored on the nitrogen-doped carbon, forming Cu0/Cu+/Cu-N3 active sites. This catalyst achieves a H2 production rate of 140.1 µmol/gcat/s at 210 °C, which is several times to 2 orders of magnitude higher than that of Cu-, Ni-, even Pt-based catalysts, demonstrating excellent long-term stability over 350 h at 210 °C. A mechanism investigation reveals that the Cu-N3 site facilitates water dissociation into *OH and improves *CO and *OH conversion, leading to enhanced CO conversion and H2 production kinetics.

CO2 hydrogenation to methanol over Pt functionalized Hf-UiO-67 versus Zr-UiO-67.

Sustainable methanol formation from CO2/H2 is potentially a key process in the post-fossil chemical industry. In this study, Hf- and Zr-based metal-organic framework (MOF) materials with UiO-67 topology, functionalized with Pt nanoparticles, have been tested for CO2 hydrogenation at 30 bar and 170-240°C. The highest methanol formation rate, 14 molmethanol molPt-1 h-1, was obtained over a Hf-based catalyst, compared with the maximum of 6.2 molmethanol molPt-1 h-1 for the best Zr-based analogue. However, changing the node metal did not significantly affect product distribution or apparent activation energy for methanol formation (44-52 kJ mol-1), strongly indicating that the higher activity of the Hf-based analogues is associated with a higher number of active sites. Both catalysts showed stable catalytic performance during testing under kinetic conditions, but the addition of 2 vol% water to the feed induced catalyst deactivation, in particular the Hf-MOFs. Interestingly, mainly methanol and methane formation rates decreased, while CO formation rates were less affected by deactivation. No direct correlation was found between catalytic stability and framework stability (crystallinity, specific surface area). Experimental and computational studies suggest that water adsorption strength to the MOF node may affect the relative catalytic stability of Hf-UiO-67-Pt versus Zr-UiO-67-Pt methanol catalysts.This article is part of the discussion meeting issue 'Green carbon for the chemical industry of the future'.

Mesoporous High-Entropy Alloy Films.

High-entropy alloys (HEAs) are promising materials for electrochemical energy applications due to their excellent catalytic performance and durability. However, the controlled synthesis of HEAs with a well-defined structure and a uniform composition distribution remains a challenge. Herein, a soft template-assisted electrodeposition technique is used to fabricate a mesoporous HEA (m-HEA) film with a uniform composition distribution of Pt, Pd, Rh, Ru, and Cu, providing a suitable platform for investigating structure-performance relationships. Electrochemical deposition enables the uniform nucleation and grain growth of m-HEA, which can be deposited onto many conductive substrates. The m-HEA film exhibits an enhanced mass activity of 4.2 A mgPt-1 toward methanol oxidation reaction (MOR), which is 7.2-fold and 35-fold higher than a mesoporous Pt film and commercial Pt black, respectively. Experimental characterization indicates that structural defects and a low work function of the m-HEA film offer sufficient active sites and fast electron-transfer kinetics. Furthermore, theoretical calculations demonstrate that the variety of favorable adsorption sites on multimetallic elements of HEA reduces the barriers for dehydration pathways and *CO species removal, ensuring optimal performance for complex MOR reactions. This work provides an effective approach to designing a variety of HEA catalysts with well-controlled porous structures for targeted electrocatalytic applications.