Search Results (34)

Catalytic upgrading of acetone–butanol–ethanol (ABE) mixtures provides a route to higher-value oxygenates for chemicals and fuel precursors. Here, Ni-, Ru-, and Ni–Ru-loaded ZIF-8 catalysts were prepared and evaluated for ABE upgrading, with particular emphasis on C7 oxygenate formation and the roles of reductive activation and acid–base properties. In situ Ni K-edge X-ray absorption spectroscopy showed that Ru facilitated Ni reduction during H₂ activation, while CO₂-TPD indicated increased basicity upon Ni incorporation. Among the activated catalysts, bimetallic 4Ni2RuZ8_act gave the highest 2-heptanone yield, exceeding the combined yields of the corresponding monometallic catalysts and suggesting a synergistic Ni–Ru effect. A pathway involving n-butanol dehydrogenation, C–C coupling with acetone-derived species to form 3-hepten-2-one, and subsequent hydrogenation to 2-heptanone was proposed. At 240 °C for 20 h using 20 mg of catalyst, 4Ni2RuZ8_act achieved 61.8% acetone conversion and produced 432 µmol of 2-heptanone. Reuse decreased both values by approximately 20%, accompanied by partial ZIF-8 degradation and ZnO formation. These results demonstrate the potential of multifunctional Ni–Ru/ZIF-8 catalysts for ABE upgrading toward C7 oxygenates while identifying structural stability as a key challenge for further development. Full article

Isopropyl alcohol (IPA) was synthesized via the acetone hydrogenation over silica-supported monometallic catalysts using Ni, Cu, Fe, Co, Ru, Rh, Pd, and Pt. The catalysts were characterized using X-ray diffraction (XRD), temperature-programmed reduction (TPR), and CO pulse chemisorption. Screening of the metal species revealed that the Ni/SiO₂ catalyst achieved the highest IPA yield, whereas the Cu/SiO₂ catalyst exhibited the highest turnover frequency for IPA formation (TOF_IPA). The NiCu bimetallic catalysts exhibited higher IPA yields and TOF_IPA values than the monometallic Ni and Cu catalysts and the physically mixed catalysts, respectively, indicating a synergistic effect arising from the use of NiCu bimetallic particles. TPR results showed that the reduction temperature of the NiCu bimetallic catalysts was lower than that of the individual monometallic catalysts, suggesting that, in the acetone hydrogenation reaction, Cu within NiCu bimetallic particles can dissociate H₂ at relatively lower temperatures and provide active hydrogen to the acetone adsorbate. Among the metal species investigated, NiCu bimetallic particles with loadings of 1.5 wt.% Ni and 0.5 wt.% Cu provided the most efficient active sites for converting acetone to IPA. A model for IPA synthesis via acetone hydrogenation was proposed, and the synergistic effect observed with NiCu bimetallic particles was discussed. Full article

CO and CO₂ hydrogenation provide essential routes for linking carbon resource recycling with renewable hydrogen utilization, yet the predictable design of CeO₂-based catalysts remains constrained by an incomplete understanding of how CeO₂ defect chemistry couples with interfacial reaction pathways. This review adopts a function-oriented rather than a metal-by-metal enumeration approach, covering pristine CeO₂, single-metal/CeO₂, bimetallic/CeO₂, and CeO₂–metal oxide composite catalysts. We argue that CeO₂ should not be viewed merely as an oxygen vacancy reservoir; its catalytic function arises from the coupled effects of exposed crystal facets, Ce⁴⁺/Ce³⁺ redox cycling, oxygen vacancy formation and migration, surface hydroxyl chemistry, water desorption, and dynamic metal–oxide interfaces. In methanol synthesis, methanation, the reverse water–gas shift reaction, and C₂ oxygenate formation, the same structural descriptors may promote or suppress the target pathway, depending on oxygen vacancy location, metal nuclearity, oxide basicity, and intermediate binding strength. We further discuss how Cu-Ce interfaces regulate methanol versus CO production, how Ni-, Co-, and Ru-based interfaces promote deep hydrogenation, and how Pd-, Rh-, and composite oxide systems expand oxygenate selectivity. Finally, we emphasize that future research needs to develop in situ descriptors, quantitatively distinguish different types of oxygen vacancies, and evaluate catalyst stability under realistic environments including water-rich, CO-containing, and cyclic operation conditions. Reinterpreting CeO₂ from a “reducible support” to a “programmable dynamic interface” holds promise for advancing catalyst design for selective CO_x hydrogenation to CO, methane, methanol, and higher-carbon oxygenates. Full article

Microalgae are promising feedstocks for third-generation bio-oil, yet direct hydrothermal liquefaction (HTL) produces bio-oil with high nitrogen/oxygen contents and low higher heating value. In this work, pretreated Spirulina was used as feedstock, with formic acid as an in situ H₂ donor. Two catalytic systems, including noble metal mixtures and non-noble Ni-Cu/ZrO₂ alloys, were constructed to investigate their regulation effects on bio-oil yield, elemental composition, and product distribution during algae HTL. When testing noble metal materials, a series of binary mixtures of Pd/C combined with Pt/C, Ru/C, and Rh/C outperformed monometallic catalysts. The optimal performance was achieved at a Pd/C to Rh/C mass ratio of 3:2, delivering a maximum bio-oil yield of 56.51 wt% and a minimum nitrogen content of 2.94 wt%. Compared with non-catalytic HTL, the bio-oil yield increased by 65 wt%, while the nitrogen content decreased by 49 wt%, surpassing that of monometallic Pd/C (43.67 wt%). To address the high cost of noble metals, a series of NiCu-ZrO₂ catalysts was synthesized. ICP and XRD verified the successful formation of Ni-Cu alloy active sites. Among all catalysts, Ni₁₆Cu₄-ZrO₂ possessed superior hydrodenitrogenation capacity over noble metal catalysts; the nitrogen and oxygen contents of the corresponding bio-oil declined by 32.75 wt% and 9.54 wt% relative to the blank group, respectively. GC-MS, FTIR, and TGA confirmed that bimetallic catalysis effectively degraded nitrogen-containing heterocyclic compounds, such as indole and aniline, and facilitated cracking of high-boiling heavy fractions into light bio-oil components. A comprehensive comparison demonstrated that binary mixtures of Pd-Rh noble catalysts are suitable for high bio-oil yield scenarios, while Ni₁₆Cu₄-ZrO₂ is low-cost and features outstanding denitrogenation efficiency. Full article

Self-supported electrodes that combine high activity, durability, and low-cost manufacturing are essential for scalable alkaline water electrolysis. Here, we report a one-pot, high-current-density electrodeposition platform that grows Ni-rich bimetallic catalysts directly on a carbon fabric derived from a mass-produced bamboo-cellulose kitchen wipe (bamboo-derived carbon fabric, BCF). Using a single NiCl₂/NH₄Cl base bath containing 5 mM of a selectable secondary metal ion (Ce, Fe, W, or Mo), galvanostatic deposition at 1 A cm⁻² for 15 min produces conformal polycrystalline catalyst shells on the individual carbon fibers. The Ce-containing cathode (BCF@NiCe) delivers hydrogen evolution overpotentials of 96.8 mV at 20 mA cm⁻² and 222 mV at 1 A cm⁻², rivaling a Pt/C benchmark on the same substrate at industrially relevant current densities, which is attributed to the cooperative interface between metallic Ni and nanocrystalline, oxygen-vacancy-rich CeO_2−x together with a superhydrophilic fibrous architecture that releases fine H₂ microbubbles. Adding Fe to the same bath yields a Ni–Fe–Ce anode (BCF@NiFeCe) that outperforms a RuO₂ benchmark for oxygen evolution above 0.1 A cm⁻² (η = 312 mV at 0.1 A cm⁻²) with a Tafel slope of 60 mV dec⁻¹. Both electrodes operate stably for 200 h of continuous electrolysis, with the Ni/CeO_2−x nanostructure, the oxygen-vacancy population, and the surface chemical states fully preserved after the test, and the same protocol extends to Ni–W and Ni–Mo on nickel foam, establishing a versatile, low-cost route to high-current-density electrodes for green hydrogen production. Full article

Ammonia (NH₃) is a compelling carbon-free hydrogen carrier. Its catalytic decomposition to produce a hydrogen/nitrogen (H₂/N₂) gas stream is central to the “NH₃-H₂” clean energy cycle, provided that residual NH₃ is removed to fuel-cell-grade purity downstream. This review integrates advances from the past five years across four major catalytic NH₃ decomposition pathways, encompassing conventional thermocatalysis, plasma-catalytic, photo(thermal), and electrically driven catalysis, within a unified mechanistic and practical framework, distinguishing it from existing single-pathway reviews. Noble metal catalysts, particularly Ru-based systems, achieve superior low-temperature activity through support engineering, promoter effects, and active-site construction. However, our analysis reveals that non-noble metal (Fe, Co, Ni) catalysts and their alloys, nitrides, and carbides have made substantial progress, with certain Co-based and bimetallic systems approaching Ru-level performance via interfacial oxygen vacancy engineering and electronic structure modulation. Emerging non-thermal routes effectively overcome thermodynamic barriers, enabling operation at temperatures 200–300 °C below conventional thermal requirements, though each faces distinct challenges in energy efficiency, stability, and scalability. Key challenges remaining across all pathways to practical implementation, including residual NH₃ removal and H₂ purification, catalyst deactivation and stability, heat management and energy efficiency, start-up/shut-down dynamics, as well as system integration and economics, are critically assessed. This review provides theoretical guidance and practical recommendations for developing scalable, low-temperature NH₃ decomposition technologies. Full article

This review analyzes the catalytic routes for the Power-to-X (PtX) conversion of hydrogen to methane, methanol, ammonia, formic acid, and synthetic hydrocarbon fuels. The key reactive synthesis technologies and catalysts for each vector are described. Recent studies and pilot projects summarizing the reaction pathways of each vector and the associated catalyst technologies are also discussed. The analysis indicates that catalyst selection critically influences the efficiency and selectivity of these reactive systems. Some catalyst synthesis routes rely on expensive critical minerals (e.g., Ru and Rh), which raise technical and economic challenges for their industrial application. Catalyst deactivation and scale-up limitations are also relevant issues to be resolved. Emerging catalysts (e.g., Fe–Co or Co–Ni bimetallics, core–shell materials, metal-organic frameworks (MOFs), electrides, covalent-organic frameworks (COFs), and perovskites) are being explored to enhance stability, selectivity, and deactivation. Europe leads PtX development to consolidate the industrial production of hydrogen-based vectors with strong policy support, while the industrial initiatives in Latin America are limited (for instance, Chile’s green methanol and ammonia projects are examples) despite its great potential to generate renewable energy. In summary, Power-to-X can store renewable energy and close the carbon loop; however, its industrial consolidation demands catalyst innovation and supportive regulatory frameworks to overcome the challenges highlighted in this review. Full article

Industrial catalysts are accelerating the global transition toward renewable energy, serving as enablers for innovative technologies that enhance efficiency, lower costs, and improve environmental sustainability. This review explores the pivotal roles of industrial catalysts in hydrogen production, biofuel generation, and biomass conversion, highlighting their transformative impact on renewable energy systems. Precious-metal-based electrocatalysts such as ruthenium (Ru), iridium (Ir), and platinum (Pt) demonstrate high efficiency but face challenges due to their cost and stability. Alternatives like nickel-cobalt oxide (NiCo₂O₄) and Ti₃C₂ MXene materials show promise in addressing these limitations, enabling cost-effective and scalable hydrogen production. Additionally, nickel-based catalysts supported on alumina optimize SMR, reducing coke formation and improving efficiency. In biofuel production, heterogeneous catalysts play a crucial role in converting biomass into valuable fuels. Co-based bimetallic catalysts enhance hydrodeoxygenation (HDO) processes, improving the yield of biofuels like dimethylfuran (DMF) and γ-valerolactone (GVL). Innovative materials such as biochar, red mud, and metal–organic frameworks (MOFs) facilitate sustainable waste-to-fuel conversion and biodiesel production, offering environmental and economic benefits. Power-to-X technologies, which convert renewable electricity into chemical energy carriers like hydrogen and synthetic fuels, rely on advanced catalysts to improve reaction rates, selectivity, and energy efficiency. Innovations in non-precious metal catalysts, nanostructured materials, and defect-engineered catalysts provide solutions for sustainable energy systems. These advancements promise to enhance efficiency, reduce environmental footprints, and ensure the viability of renewable energy technologies. Full article

This review explores CO₂ methanation and steam methane reforming (SMR) as two key thermochemical processes governed by reversible reactions, each offering distinct contributions to carbon-neutral energy systems. The objective is to provide a comparative assessment of both processes, highlighting how reaction reversibility can be strategically leveraged for decarbonization. The study addresses methane production via CO₂ methanation and hydrogen production via SMR, focusing on their thermodynamic behaviors, catalytic systems, environmental impacts, and economic viability. CO₂ methanation, when powered by renewable hydrogen, can result in emissions ranging from −471 to 1076 kg CO₂-equivalent per MWh of methane produced, while hydrogen produced from SMR ranges from 90.9 to 750.75 kg CO₂-equivalent per MWh. Despite SMR’s lower production costs (USD 21–69/MWh), its environmental footprint is considerably higher. In contrast, methanation offers environmental benefits but remains economically uncompetitive (EUR 93.53–204.62/MWh). Both processes rely primarily on Ni-based catalysts, though recent developments in Ru-based and bimetallic systems have demonstrated improved performance. The review also examines operational challenges such as carbon deposition and catalyst deactivation. By framing these technologies through the shared lens of reversibility, this work outlines pathways toward integrated, efficient, and circular energy systems aligned with long-term sustainability and climate neutrality goals. Full article

A rational design strategy for active sites on the catalyst surface can effectively enhance CO₂ reduction reaction (CO₂RR) selectivity. Transition metal atoms from the fourth (Sc–Ni) and fifth (Y–Mo, Ru–Pd) periods were doped onto the In₂S₂X (X = Se, Te) surface to control bimetallic active sites. The study showed that the d-band center’s position of the dopant atom significantly influences CO₂RR selectivity. Cations with positive d-band centers further from the Fermi level are more inclined towards CH₂O, while those with negative d-band centers closer to the Fermi level favor HCOOH; cations with d-band centers near the Fermi level exhibit a strong preference for CH₃OH. This study systematically elucidates the intrinsic mechanisms and offers a significant theoretical foundation for developing highly selective photocatalysts. Full article

Using anthropogenic carbon dioxide (CO₂) as a feedstock for the production of synthetic fuel has gained significant attention in recent years. Among the various CO₂ conversion pathways, the production of synthetic natural gas via CO₂ methanation holds promise because of its potential for both carbon recycling and renewable energy storage. Nickel (Ni) and ruthenium (Ru) are the dominant metals employed as catalysts in the CO₂ methanation reaction. This review summarizes the research landscape of Ni- and Ru-based catalysts over the last ten years. Bibliometric analysis revealed that China has the highest number of publications, the Chinese Academy of Sciences is the foremost academic institution, and the International Journal of Hydrogen Energy is the leading journal in this area of research. The publication trend revealed that research on Ni-based catalysts is published at almost four times the rate of Ru-based catalysts. Despite growth in research, problems with catalyst stability and kinetics still exist. The latest research on various catalytic systems, including supported, bimetallic, and single-atom catalysts and the fundamental challenges associated with the CO₂ methanation process are reviewed. This review provides a new angle for future studies on catalysts based on non-noble Ni and noble Ru metals and opens the way for additional research in this area. Full article

The high viscosity and oxygen content of pyrolysis crude oil hinder the advancement of pyrolysis technology. To address the issue, this study conducted hydrodeoxygenation upgrading experiments on pyrolysis crude oil using hydrothermal directional conversion. A variable analysis was performed to assess the differences in upgrading effects based on the active metal (Ru, Pt) and the supports (activated carbon, Nb₂O₅, MgO) of the supported catalyst, and further investigations were conducted on the catalyst with bimetallic doping modification. Optimal reaction conditions were determined by adjusting the reaction temperature. Additionally, directional conversion studies of model compounds were carried out to elucidate the reaction pathway. The results indicated that the Pt/MgO catalyst achieved the highest yield of stable and combustible compounds (hydrocarbons, alcohols, ethers, esters, and ketones), with a yield of 17.8 wt%. Upon modification with Ni doping, the yield increased by 49.5%. The upgrading effect improved with an increase in reaction temperature, and the yield of target compounds was 26.7 wt% at 290 °C, with an energy conversion rate of 72.6% and a selectivity of 75.8%. Moreover, the physicochemical properties of the upgraded oil were similar to those of ethanol. All three model compounds underwent 100% conversion. This study provides both experimental support and a theoretical foundation for the further development of biomass conversion technology. Full article

CO selective methanation is regarded as an efficient technological solution for hydrogen-rich gas purification in fuel cells. In this study, a series of bimetallic catalysts (Ru-Ni/xTiO₂-MgAl₂O₄) were synthesized by impregnation method after surface modification of MgAl₂O₄ supports with different contents of TiO₂. The prepared catalysts were characterized by XRD, BET, SEM, TEM, H₂-TPR, CO-TPD, NH₃-TPD, and XPS. The Ru-Ni/10TiO₂-MgAl₂O₄ exhibited excellent CO-SMET performance, removing the CO in the H₂-rich gas to less than 10 ppm with the selectivity above 50% in a temperature window range of 210–280 °C. The results showed that the TiO₂-modified MgAl₂O₄ support not only improved the interaction between metal and support, and promoted the dispersion of active component nanoparticles on the support, but also introduced oxygen vacancies or defects in the catalyst and enhanced the acidity, resulting in better catalytic activity and stability. Full article

This work aims at the effects of anion-exchange membranes (AEMs) and ionomer binders on the catalyst electrodes for anion-exchange membrane fuel cells (AEMFCs). In the experiments, four metal catalysts (nano-grade Pt, PtRu, PdNi and Ag), four AEMs (aQAPS-S8, AT-1, X37-50T and X37-50RT) and two alkaline ionomers (aQAPS-S14 and XB-7) were used. They were verified through several technical parameters examination and cell performance comparison for the optimal selection of AMEs. The bimetallic PdNi nanoparticles (PdNi/C) loaded with Vulcan XC-72R carbon black were used as anode electrodes by using the wet impregnation method, and Ag nanoparticles (Ag/C) were used as the catalyst cathode. It was found that the power density and current density of the X37-50RT are higher than the other three membranes. Also, alkaline ionomers of XB-7 had better performance than aQAPS-S14. The efficiency was improved by 32%, 155% and 27%, respectively, when compared to other membranes by using the same catalyst of PdNi/C, Ag/C and Pt/C. The results are consistent with the membrane ion conductivity measurements, which showed that the conductivity of the X37-50RT membrane is the highest among them. The conductivity values for hydroxide ions (OH⁻) and bromide ions (Br⁻) are 131 mS/cm and 91 mS/cm, respectively. These findings suggest that the properties (water uptake, swelling rate and mechanical) of the anion-exchange membrane (AEM) can serve as a key reference for AEM fuel cell applications. Full article

Polyols such as 1,5-pentadiol, 1,6-hexanediol, and 1,2,6-hexanetriol are crucial chemicals, traditionally derived from non-renewable fossil sources. In the pursuit of sustainable development, exploring renewable and environmentally benign routes for their production becomes imperative. Furfural and 5-hydroxymethylfurfural are C₅ and C₆ biomass-derived platform molecules, which have potential in the synthesis of various polyols through hydrogenation and hydrogenolysis reactions. Currently, there is an extensive body of literature exploring the transformation of biomass-derived furan compounds. However, a comprehensive review of the transformation of furan compounds to polyols is lacking. We summarized the literature from recent years about the ring-opening reaction involved in converting furan compounds to polyols. This article reviews the research progress on the transformation of furfural, furfuryl alcohol, and 2-methylfuran to 1,2-pentadiol, 1,4-pentadiol, 1,5-pentadiol, and 1,2,5-pentanetriol, as well as the transformation of 5-hydroxymethylfurfural to 1,2-hexanediol, 1,6-hexanediol, and 1,2,6-hexanetriol. The effects of the supported Pd, Pt, Ru, Ni, Cu, Co, and bimetallic catalysts are discussed through examining the synergistic effects of the catalysts and the effects of metal sites, acidic/basic sites, hydrogen spillover, etc. Reaction parameters like temperature, hydrogen pressure, and solvent are considered. The ring opening catalytic reaction of furan rings is summarized, and the catalytic mechanisms of single-metal and bimetallic catalysts and their catalytic processes and reaction conditions are discussed and summarized. It is believed that this review will act as a key reference and inspiration for researchers in this field. Full article