ACS Catalysis 最新文献

Intermetallic compounds serve as model catalysts for selective hydrogenation reactions, offering precise control over the active site composition(s), geometric and electronic structure. The addition of a third element to form a ternary intermetallic alters the exposed crystal facet(s), demonstrating a strategy to impart improved catalytic behavior in intermetallic catalysts. The site-specific substitution of a small fraction of Pd atoms with Au in pyrite-type PdSb₂ results in the preferential exposure of the (100) facet over the (111) facet. Electron back scattered diffraction and density functional theory calculations confirm the facet change upon the substitution of Pd with Au to form the ternary Pd_1–xAu_xSb₂ (0.075 ≤ x ≤ 0.25). The (100) facet demonstrates higher net alkene selectivity due to significantly weaker alkene binding compared to the (111) facet. Distinct from our prior work on chemical substitution to directly alter the active site composition, this work demonstrates the indirect modification of active sites via preferential facet exposure.

This work investigates Ru-CeO₂–TiO₂ catalysts for the CO₂ methanation reaction and compares their performance with that of previously studied Ru-CeO₂ systems. Despite the lower Ru loading, the TiO₂-containing catalysts exhibit a significantly higher activity. To understand this behavior, in situ X-ray absorption spectroscopy (XAS) was carried out at the Ru K-edge and Ce L₃-edge. Unlike Ru-CeO₂, which displays the reversible redox behavior of Ru, the Ru-CeO₂–TiO₂ catalysts show irreversible Ru reduction and a substantially higher fraction of Ce³⁺ species under all tested conditions (H₂, CO₂, H₂/CO₂). The stabilization of metallic Ru during methanation, together with the enhanced formation of Ce³⁺ promoted by TiO₂ through interfacial electronic transfer, accounts for the catalyst’s high activity. Complementary in situ DRIFTS measurements reveal the formation and rapid consumption of bidentate carbonates and formates. These species act as a key intermediate in methane formation. Overall, these findings highlight the crucial role of the mixed CeO₂–TiO₂ oxide in tuning the surface chemistry of the catalysts by stabilizing metallic Ru, enhancing ceria reducibility, and promoting efficient reaction pathways for CO₂ methanation. The manipulation of metal ↔ oxide–oxide interactions can be a very useful tool when dealing with the valorization of CO₂.

Copper catalysis offers an attractive earth-abundant alternative to noble-metal-based carbonylation, yet its application to aryl electrophiles remains severely limited due to the low redox flexibility of Cu(I) and the inhibiting effect of CO coordination. Here we report a photocatalyst-free strategy that overcomes these intrinsic limitations by exploiting in situ generated NHC-stabilized aryl-Cu(I) complexes as bifunctional catalytic species capable of both light absorption and aryl-group transfer. This platform enables the development of copper-catalyzed carbonylation of arylboronic esters using aryl thianthrenium salts as electrophilic coupling partners. The method exhibits a broad substrate scope and high functional-group compatibility, accommodating diverse electron-rich and electron-deficient aromatics as well as structurally complex late-stage scaffolds. This work introduces a generalizable design principle for activating aryl electrophiles under copper catalysis and establishes a dual-functional reactivity mode for Cu(I) species in carbonylation chemistry.

Controlling the dynamic mobility of catalyst surface active sites and their interactions with the surrounding environment is critical in generating active surfaces that directly influence catalytic activity and selectivity. Here, we report a strategy for tailoring the dispersion and electronic environment of single-atom Rh catalysts by decorating the alumina support with highly dispersed (HD) cerium and molybdenum oxides. The resulting catalysts exhibit markedly different behaviors in the Reverse Water–Gas Shift (RWGS) reaction. In particular, Rh/MoO_x(HD)/Al₂O₃ maintains atomically dispersed Rh even at elevated temperatures (up to 400 °C), achieving CO selectivity of up to 100% and resisting sintering via the formation of a newly developed structure featuring Rh single atoms embedded in MoO_x clusters. In situ spectroscopy and microscopy analyses confirm the stabilization of Rh and the dynamic evolution of the Rh–Mo coordination under the reaction conditions. Our findings highlight the power of support modification in steering active site structure and activity, offering a pathway toward enhanced performance and tunable single-atom catalysts for CO₂ valorization.

Electrooxidation reaction of ethylene glycol (EG) offers an efficient route for producing value-added chemicals (glycolic acid (GA)) and facilitates coupled hydrogen (H₂) production. However, its practical performance is often hindered by sluggish reaction kinetics and catalyst deactivation, both of which are strongly influenced by interfacial microenvironments. Here, we report an interfacial engineering strategy that employs polydopamine (PDA) to modulate the hydrogen-bonding network at the Au catalyst-electrolyte interface, which mitigates the oxidative deactivation of Au, achieving a 1.78-fold enhancement for electrooxidation of EG-to-GA compared with the pure Au catalyst (0.41 vs 0.23 mmol cm^–2 h^–1 at 1.5 V vs RHE). Mechanistic studies reveal that Au sites generate reactive OH* species to drive EG oxidation, and the PDA layer enriches EG near active sites. Moreover, PDA can regulate the interfacial hydrogen-bonding network, that is, generating strong hydrogen bonding with EG disrupts the tetrahedral water network, generating a more open and dynamic hydration environment that facilitates EG adsorption and activation. When integrated into a flow-cell electrolyzer, Au/PDA catalyst delivers efficient coproduction of glycolic acid (3.0 mmol h^–1) and hydrogen (8.1 mmol h^–1) with high selectivity under a 0.8 V operating voltage. This work elucidates a molecular-level mechanism for hydrogen-bond-mediated interfacial regulation and establishes a general design principle for enhancing alcohol electrooxidation through adaptive hydrogen-bonding engineering.

Engineered luciferases have transformed biological imaging and sensing, yet optimizing NanoLuc luciferase (NLuc) remains challenging due to the inherent stability-activity trade-off and its limited sequence homology with characterized proteins. We report a hybrid approach that synergistically integrates deep learning with structure-guided rational design to develop enhanced NLuc variants that improve thermostability and thereby activity at elevated temperatures. By systematically analyzing libraries of engineered variants, we established that modifications to termini and loops distal from the catalytic center, combined with preservation of allosterically coupled networks, effectively increase thermal resilience while maintaining enzymatic function. Our optimized variants─notably B.07 and B.09─exhibit substantial thermostability enhancements (increased melting temperatures of 7.2 and 5.1 °C, respectively), leading to the sustained activity of a high-activity mutant at elevated temperatures. Molecular dynamics simulations and protein folding studies elucidate how these mutations favorably modulate conformational landscapes without perturbing the substrate binding architecture. Beyond providing a thermostabilized tool for bioluminescence applications, our integrated methodology presents a framework for engineering enzymes when traditional homology-based approaches fail and stability-activity constraints present formidable barriers to improvement.

Subsurface hydrogen transport in alloys offers poison resistance and enhanced adsorption capacity compared to surface-mediated processes, yet its underlying dynamic mechanisms remain largely elusive. Herein, we employ machine learning-accelerated molecular dynamics simulations to investigate atomic-scale hydrogen spillover dynamics in Pt₁/Ag single-atom near-surface alloys. We identify two distinct penetration pathways: a H–H collision-induced mechanism, where impulsive interactions between dissociated H atoms at the Pt₁ site transiently enhance the vertical kinetic energy of one atom, enabling barrier overcoming and subsurface entry; and a surface spillover-mediated mechanism, involving initial hopping of hydrogen species across Ag sites coupled with stabilization from subsurface Pt atoms that collectively facilitate subsequent penetration. In addition, subsurface diffusion shows higher mobility and a stronger temperature response than surface diffusion. These findings provide fundamental insights into subsurface hydrogen transport and establish design principles for advanced catalytic and hydrogen storage systems through subsurface engineering.