Search

Abstract In-plane sulfur vacancies (Sv) in molybdenum disulfide (MoS2) were newly unveiled for CO2 hydrogenation to methanol, whereas edge Sv were found to facilitate methane formation. Thus, selective exposure and activation of basal plane is crucial for methanol synthesis. Here, we report a mesoporous silica-encapsulated MoS2 catalysts with fullerene-like structure and atomic copper (Cu/MoS2@SiO2). The main approach is based on a physically constrained topologic conversion of molybdenum dioxide (MoO2) to MoS2 within silica. The spherical curvature enables the generation of strain and Sv in inert basal plane. More importantly, fullerene-like structure of few-layer MoS2 can selectively expose in-plane Sv and reduce the exposure of edge Sv. After promotion by atomic copper, the resultant Cu/MoS2@SiO2 exhibits stable specific methanol yield of 6.11 molMeOH molMo –1 h–1 with methanol selectivity of 72.5% at 260 °C, much superior to its counterparts lacking the fullerene-like structure and copper decoration. The reaction mechanism and promoting role of copper are investigated by in-situ DRIFTS and in-situ XAS. Theoretical calculations demonstrate that the compressive strain facilitates Sv formation and CO2 hydrogenation, while tensile strain accelerates the regeneration of active sites, rationalizing the critical role of strain.

ABSTRACTNanoparticles composed of metallic cores encapsulated in oxide shells emerged in the last decade as an attractive class of nanocomposite materials due to their high stability and unique properties provided by the high contact area between the metal and oxide components. Diverse metal-oxide interactions in metal@oxide core@shell nanoparticles enable tuning their electronic structure, spectroscopic properties, and surface reactivity for applications in sensing, electrochemistry, batteries as well as thermal and photocatalysis. Herein, we review the recent literature on the synthesis, characterization, simulations, and applications of metal@oxide nanocomposites. In particular, we discuss how the properties of metal@oxide nanoparticles can be tuned for a given application by changing the size of the metal core, the thickness and porosity of the oxide shell, as well as their composition, e.g. by alloying the core or doping the shell. Understanding of structure-property relations in metal@oxide systems provides vast opportunities for the rational design of advanced metal@oxide nanocomposites, making this class of materials promising for a wide range of applications.

One major technological obstacle for membrane-based alkaline water electrolyzer is the inefficient hydrogen evolution reaction. Here, the authors report a platinum/fullerene heterostructure catalyst, which shows enhanced activity for hydrogen production due to the diverse interface between platinum and fullerene.

Boosting activity of oxide catalysts is a long-lasting challenge to developing efficient catalysts for industrially important reactions such as CO2-to-methanol. Here, the authors report a strategy for enhancing the activity of a ZnZrO x methanol synthesis catalyst via engineered nanoscale H supply.

Abstract Alloy nanoparticles (nanoalloys) are widely applied in heterogeneous catalysts, advanced electrodes, biomaterials, and other areas. The properties of nanoalloys can be tuned to a significant extent by their structures and compositions, which are governed by the employed synthetic procedure. Often such synthesis occurs in non‐equilibrium conditions and yields nanoalloys with structures and properties that are different from those obtained in thermodynamic equilibrium. In this work, we characterize how the non‐equilibrium conditions during the synthesis of Cu–Au alloys via physical vapor deposition (PVD) affect their morphology, composition, electronic structure, and reactivity in CO oxidation. We used molecular dynamics to simulate the PVD synthesis of Cu–Au nanoalloys through the non‐isothermal aggregation of Cu and Au atoms at a 3:1 ratio in the Ar atmosphere to obtain realistic structures of Cu–Au nanoparticles. Due to the different aggregation kinetics of Au and Cu atoms, the average Au concentration in the obtained Cu–Au particles varied between 14% and 50% depending on the nanoparticle size and the aggregation time. Density functional simulations revealed that the reactivity of the obtained Cu–Au clusters toward CO and oxygen as well as Brønsted–Evans–Polanyi relations for CO oxidation significantly depend on whether the clusters had fcc, icosahedral, or amorphous structures and do not strongly correlate with the d‐band centers of the adsorption sites. Our study highlights the importance of the non‐equilibrium character of nanoalloy structure and composition for their electronic structure and catalytic properties. The performed analysis of the reactivity of Cu–Au clusters with realistic structures in CO oxidation will help the optimization of Cu–Au catalysts for this societally important reaction.