Two-dimensional MoS2 nanosheets (NSs) with high active site density were designed for the hydrogen evolution reaction (HER) through a microdomain reaction method. The effect of the annealing temperature on the microstructure and the HER performance of MoS2 NSs was examined, and a plausible relation between the stack structures of the MoS2 catalysts and their HER performance was also explored. The MoS2 NS electrocatalyst obtained at 550 °C reveals the best HER performance with a relatively small Tafel slope of 68 mV/dec. Both the exposed surface area and active site density are very important for providing a large amount of active sites. The present work has been proved to be an efficient route to achieve a high active site density and a relatively large surface area, which might have potential use in photoelectrocatalytic water splitting.

Ligand utilization is a necessary and powerful technique for the colloidal synthesis of nanoparticles (NPs) with controllable sizes and regulated morphologies. For catalysis applications, it is commonly believed that surface ligands on metal NPs block the active catalytic sites and reduce the catalytic activity. Nevertheless, since 2010, an increasing number of research groups have demonstrated the unexpected benefits of ligands that improve catalytic activity and/or selectivity. These benefits can be ascribed to the construction of an inorganic−organic interface, through which a series of factors, such as steric, electronic, and solubility effects, can be utilized to produce favorable changes to the interfacial environment. Considering the tremendous number of developments in this emerging research field, it is necessary to compile a comprehensive and systematic overview of recent advances. In this Review, we summarize the critical impacts of ligands on heterogeneous nanocatalysis. First, we introduce the vital roles of ligands in colloid syntheses for controllable sizes and regulated shapes. Second, the detrimental effects of ligands for nanocatalysis are described on the basis of traditional views. Third, a series of strategies for ligand removal are reviewed and compared. Fourth, on the basis of research that has been conducted in the past decade, the three main beneficial ligand effects (steric, electronic, and solubility) on heterogeneous nanocatalysis are classified and discussed. For each effect, the possible corresponding beneficial mechanism is presented, and typical examples are provided. Recent advances regarding density functional theory (DFT) calculations and the regulation of ligand surface coverage have been dedicated to explaining the ligand-promotion mechanism in nanocatalysis and searching for optimal nanocatalysts. Fifth, the stabilities of cutting-edge ligand-capped nanocatalysts before and after catalytic reactions are discussed. Finally, we highlight the remaining challenges and propose future perspectives. Although much progress has been achieved, the impacts of ligands on the catalytic activities of nanocatalysts are multifaceted and still debatable. We hope this Review will deepen readers' understanding of the actual impacts ligands have on heterogeneous catalysis.

Supported Ag nanocomposites and bimetallic Ag-based nanocomposites with various morphologies and compositions engineered for representative catalytic applications are reviewed.

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Rational synthesis of bi- or multi-metallic nanomaterials with both dendritic and porous features is appealing yet challenging. Herein, with the cubic Cu2O nanoparticles composed of ultrafine Cu2O nanocrystals as a...

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PtSe2 is a typical noble metal dichalcogenide (NMD) that holds promising possibility for next‐generation electronics and photonics. However, when applied in hydrogen evolution reaction (HER), it exhibits sluggish kinetics due to the insufficient capability of absorbing active species. Here, we construct PtSe2/Pt heterointerface to boost the reaction dynamics of PtSe2, enabled by an in situ electrochemical method. It is found that Se vacancies are induced around the heterointerface, reducing the coordination environment. Correspondingly, the exposed Pt atoms at the very vicinity of Se vacancies are activated, with enhanced overlap with H 1s orbital. The adsorption of H. intermediate is thus strengthened, achieving near thermoneutral free energy change. Consequently, the as‐prepared PtSe2/Pt exhibits extraordinary HER activity even superior to Pt/C, with an overpotential of 42 mV at 10 mA cm−2 and a Tafel slope of 53 mV dec−1. This work raises attention on NMDs toward HER and provides insights for the rational construction of novel heterointerfaces.

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