Nitrogen-doped graphene single-atom catalysts (SACs) have shown remarkable promise in selective hydrogenation and hydrogen storage. However, the rationalization of hydrogen evolution in these systems is still challenging. In this paper, by systematically calculating hydrogen adsorption and dissociation energies on active 3-fold sites M-C3-xNx, with x ranging from 0 to 3 and with M = Co, Ni, Pd, we show that hydrogen dissociation is endothermic─except for Pd-N3 and Pd-CN2─and proceeds via two distinct mechanisms, depending on the nitrogen content of the site. For nitrogen-poor sites, dissociation follows a heterolytic pathway with a relatively high activation energy (0.6-1.1 eV), with a notable exception being the Pd-C2N site with a low barrier (0.37 eV). In contrast, nitrogen-rich sites favor homolytic dissociation, with a significantly lower activation barrier (below 0.4 eV). However, for Ni-N3, the electronic confinement of hydrogen imposed by nitrogen neighbors prevents true homolytic dissociation, with the two dissociated H atoms on the metal spontaneously recombining. Across all N-doped graphene SAC models considered, the calculated activation barriers exhibit a Brønsted-Evans-Polanyi scaling. This study provides a detailed understanding of hydrogen dissociation on graphene SACs, paving the way for the design of catalysts tailored to specific applications.

Pd-Te alloy inside hollow silica nanospheres for semi‑hydrogenation of dehydrolinalool to linalool.

Tuning e-fuel selectivity in sorption-enhanced CO2 hydrogenation over In2O3/ZrO2: The effect of LTA and FAU zeolites

Carbon-decorated alumina supports for synergistic optimization of nickel catalysts in selective pyridine hydrogenation to piperidine

Metallic bismuth-embedded mesoporous carbon hollow spheres for highly selective electrocatalytic hydrogen peroxide production via two-electron oxygen reduction

Ammonization-treated CuMo catalyst for efficient and selective CO2 hydrogenation to methanol

ZIF-67 derived hollow carbon with embedded Co nanoparticles for highly selective hydrogenation of HMF to 2,5-dihydroxymethylfuran

Insights into the role of multiple dopants in Fe-based catalysts for the selective hydrogenation of CO2 to liquid hydrocarbons

Catalytic performance of Fe modified Co-Mo/γ-Al2O3 catalysts for selective hydrogenation of polycyclic aromatic hydrocarbons

Nickel nanoparticles embedded in N-doped carbon efficient selective hydrogenation of cinnamaldehyde in aqueous phase

Abstract Aviation is a major contributor to greenhouse gas emissions, and thus developing renewable alternatives such as lignin-derived biofuels is critical. Current catalytic routes for hydrodeoxygenation of bio-oil model compounds, such as isoeugenol, fail to produce the desired aromatics to cycloalkane ratios required for aviation fuels. We hypothesized that tailoring metal-support interactions in a nickel aluminate spinel catalyst can enable selective formation of hydrocarbon blends meeting fuel specifications. Hydrodeoxygenation of isoeugenol was conducted in a batch reactor using a nickel aluminate spinel catalyst synthesized via a one-pot sol-gel method. Reactions were conducted at 250–300 °C and 20–40 bar hydrogen pressure, and products were analyzed by gas chromatography-mass spectrometry to determine yields of aromatics, cycloalkanes, and intermediates. Catalyst structure and surface properties were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and electron microscopy to establish structure–performance relationships. Under optimized conditions of 275 °C at 20 bar H 2 , aromatic and cycloalkane yields reached 16 wt% and 30 wt%, respectively. Reaction trends showed that elevated temperatures favor cycloalkane formation while hydrogen pressure controls intermediate conversion. The moderate Lewis acidity combined with medium-sized Ni 0 crystallites promote selective hydrogenation and deoxygenation while minimizing over-hydrogenation. This catalytic system produces fuel-grade hydrocarbon mixtures in a single step, exceeding previously reported performance. These findings provide a practical route for lignin valorization and the production of renewable aviation fuels with reduced greenhouse gas emissions.

Partial oxidation of methane is a highly attractive route for hydrogen-rich syngas production, provided that high H2 yields and H2/CO ratios above 3 can be achieved. Herein, we demonstrate that precise compositional tuning of Ni–Cu bimetallic catalysts supported on Gd-doped CeO2 enables direct control over defect chemistry and reaction pathways in partial oxidation of methane. A systematic investigation of Ni/Cu ratios was conducted to elucidate composition–structure–activity relationships using X-ray diffraction, Raman spectroscopy, temperature-programmed reduction/oxidation/desorption, and thermogravimetric analysis. While monometallic 5%Ni/GDC and promoted 1%Re4%Ni/GDC exhibited high methane conversion, they failed to deliver optimal hydrogen selectivity. In contrast, introducing Cu within a narrow compositional window fundamentally altered the reaction mechanism. The 2.5%Ni2.5%Cu/GDC catalyst showed limited oxygen vacancy formation and pronounced carbon deposition, leading to inferior catalytic performance. Remarkably, the 3.5%Ni1.5%Cu/GDC catalyst maximized both oxygen vacancy density and surface basicity, thereby selectively activating CO2- and H2O-assisted oxidation routes and enforcing the exclusive dominance of indirect POM pathways. This defect-mediated pathway control effectively decoupled methane activation from hydrogen-consuming side reactions while simultaneously promoting hydrogen-forming, CO-consuming reactions, most notably the water–gas shift reaction. As a result, the optimized 3.5%Ni1.5%Cu/GDC catalyst achieved an H2 yield of 84% with an H2/CO ratio of 3.11 and maintained stable operation for 40 h on stream at 600 °C. These findings establish Ni–Cu compositional tuning as a powerful strategy for defect engineering and reaction pathway regulation, providing new design principles for efficient and durable partial oxidation of methane catalysts targeting hydrogen-rich syngas production.

Selective hydrogen gas sensing using spincoated ZnO thin films

During the pre-hydrotreatment process, the hydrogen sulfide and ammonia present in the reaction atmosphere affect the conversion rate of bicyclic aromatics and the retention rate of monocyclic aromatic hydrocarbons (RRMA). In this study, 1-Methylnaphthalene (1-MN) is used to investigate hydrogenation behavior on Ni-Mo-S active sites. The results indicate that at low conversion rates, 1-MN is preferentially converted to 5-methyltetrahydronaphthalene (5-MTHN) on the S-edge, and can be simultaneously converted to 1-methyltetrahydronaphthalene (1-MTHN) and 5- MTHN on the Mo-edge. Additionally, the H2S in the reaction atmosphere significantly competes with 1-MN for adsorption on the S-edge, limiting the hydrogenation selectivity of 5-MTHN, whereas NH3 preferentially competes with 1-MN on the Mo-edge. At a high1-MN conversion rate, the competitive adsorption of 1-MN and MTHN is concentrated on the S-edge. Conversely, at a low bicyclic aromatic conversion rate, H2S increases the RRMA, whereas NH3 significantly lowers it.

Ligand-Directed Divergent Selectivities in Cobalt-Catalyzed Transfer Hydrogenation of Quinolines: Insights from Experiment and Theory

ABSTRACT Precise control of chemical ordering in bimetallic nanocatalysts offers a route to decouple activity and selectivity in acetylene hydrogenation, but direct atomic‐scale evidence linking surface order to catalytic performance is scarce. Here, we tune Pd‐Cu nanoalloys from chemically disordered to highly ordered states by composition control and targeted H 2 thermal treatment. Under near‐industrial conditions, all catalysts reach full acetylene conversion between 100°C and 120°C, whereas the ethylene selectivity enhances with the chemical ordering increasing. By combining synchrotron X‐ray absorption fine structure (XAFS) with X‐ray total scattering and reverse Monte Carlo (RMC) simulation, three‐dimensional atomic models are reconstructed to quantitatively map surface coordination. Compared with the chemically disordered Pd‐Cu nanocatalyst, the highly ordered PdCu shows an increase in average surface Pd‐Cu coordination and an expansion of mean surface Pd‐Pd separations. These structural features weaken ethylene binding and suppress re‐adsorption, rationalizing the enhanced selectivity. Our study provides direct atomic‐scale evidence connecting chemical order to catalytic selectivity and opens the way for guiding the precise design of bimetal nanocatalysts.

Abstract Single‐site pairs are promising in achieving high selectivity and activity in alkyne semihydrogenation, but its applicability is limited by the insufficient activity because pair sites cannot adsorb and activate alkyne. Here, we couple single‐site Pd with Jahn–Teller active Cu atoms of Cu‐doped Fe 2 O 3 to construct a highly active and stable single‐site Pd‐Cu pairs. The Jahn–Teller active Cu possesses elongated axial orbitals, and the strong electronic coupling between Pd and Cu further contributes to their unoccupied axial d orbitals, which helps Pd‐Cu pair to cooperatively activate C 2 H 2 molecule, unlike ordinary single‐site pairs where only H 2 is activated. As a result, this catalyst exhibits state‐of‐the‐art performance, with > 99.99% conversion and 95.5% selectivity as well as excellent stability with negligible performance decay after 300‐h test in purifying acetylene of ethylene stream. Both in situ spectra and theoretical results indicate two H addition steps occur on Pd and Cu sites in sequence. This work opens an avenue for constructing highly efficient single‐site pairs for selective hydrogenation and beyond.

Single-site pairs are promising in achieving high selectivity and activity in alkyne semihydrogenation, but its applicability is limited by the insufficient activity because pair sites cannot adsorb and activate alkyne. Here, we couple single-site Pd with Jahn-Teller active Cu atoms of Cu-doped Fe2O3 to construct a highly active and stable single-site Pd-Cu pairs. The Jahn-Teller active Cu possesses elongated axial orbitals, and the strong electronic coupling between Pd and Cu further contributes to their unoccupied axial d orbitals, which helps Pd-Cu pair to cooperatively activate C2H2 molecule, unlike ordinary single-site pairs where only H2 is activated. As a result, this catalyst exhibits state-of-the-art performance, with>99.99% conversion and 95.5% selectivity as well as excellent stability with negligible performance decay after 300-h test in purifying acetylene of ethylene stream. Both in situ spectra and theoretical results indicate two H addition steps occur on Pd and Cu sites in sequence. This work opens an avenue for constructing highly efficient single-site pairs for selective hydrogenation and beyond.

Electrochemical hydrogenation of furfural for synthesis of furfuryl alcohol over copper oxide catalytic electrode.

Achieving simultaneous high activity, selectivity, and stability in ester hydrogenation remains a persistent challenge, largely due to the competitive adsorption of reactants at active sites. Here, we introduce an inverse NiOx-Ag interface as a general design platform to spatially decouple the activation of H2 and ester, exemplified with dimethyl oxalate (DMO). The catalyst (Ag-Ni/SiO2), synthesized via controlled partial reduction of Ni phyllosilicate followed by Ag deposition, features electron-rich Ag sites and electron-deficient interfacial Ni sites arising from interfacial electron transfer. Comprehensive characterizations reveal abundant NiOx-Ag interfaces with modified coordination and electronic structures. In situ Fourier-transform infrared spectroscopy, temperature programmed desorption/surface reaction, and H2-D2 isotope exchange experiments demonstrate that H2 is preferentially dissociated at Ag sites, while DMO adsorbs and activates on NiOx sites, effectively mitigating competitive adsorption. Theoretical calculations confirm the cooperative nature of the interface, showing low barriers for H2 dissociation and favorable desorption energetics for methyl glycolate (MG), suppressing over-hydrogenation. Accordingly, the Ag-Ni/SiO2 catalyst delivers a turnover frequency of 944.4 h-1 with ∼99% selectivity to MG over 500h of continuous operation, among the highest reported for DMO hydrogenation. This work establishes interfacial inversion engineering as a versatile approach to optimize site complementarity in multi-step catalytic transformations.