Reversible electrochemical storage of alkali metal ions is the basis of many secondary batteries. Over years, various electrode materials are developed and optimized for a specific type of alkali metal ions (Li , Na , or K ), yet there are very few (if not none) candidates that can serve as a universal host material for all of them. Herein, a facile solvothermal method is developed to prepare VS nanosheet assemblies. Individual nanosheets are featured with a few atomic layer thickness, and they are hierarchically arranged with minimized stacking. Electrochemical measurements show that VS nanosheet assemblies enable the rapid and durable storage of Li , Na , or K ions. Most remarkably, the large reversible specific capacity and great cycling stability observed for both Na and K are extraordinary and superior to most existing electrode materials. The experimental results of this study are further supported by density functional theory calculations showing that the layered structure of VS has large adsorption energy and low diffusion barriers for the intercalation of alkali metal ions.

Earlier research has been primarily focused on WC as one of the most promising earth-abundant electrocatalysts for hydrogen evolution reaction (HER), whereas the other compound in this carbide family—W2C—has received far less attention. Our theoretical calculations suggest that such a focus is misplaced and W2C is potentially more HER-active than WC. Nevertheless, the preparation of phase pure and sintering-free W2C nanostructures represents a formidable challenge. Here we develop an improved carburization method and successfully prepare ultrasmall and phase-pure W2C nanoparticles. When evaluated for HER electrocatalysis, W2C nanoparticles exhibit a small onset overpotential of 50 mV, a Tafel slope of 45 mV dec−1 and outstanding long-term cycling stability, which are dramatically improved over all existing WC-based materials. In addition, the integration of W2C nanoparticles with p-type Si nanowires enables highly active and sustainable solar-driven hydrogen production. Our results highlight the great potential of this traditionally non-popular material in HER electrocatalysis.

Most electrocatalysts for the ethanol oxidation reaction suffer from extremely limited operational durability and poor selectivity toward the CC bond cleavage. In spite of tremendous efforts over the past several decades, little progress has been made in this regard. This study reports the remarkable promoting effect of Ni(OH) on Pd nanocrystals for electrocatalytic ethanol oxidation reaction in alkaline solution. A hybrid electrocatalyst consisting of intimately mixed nanosized Pd particles, defective Ni(OH) nanoflakes, and a graphene support is prepared via a two-step solution method. The optimal product exhibits a high mass-specific peak current of >1500 mA mg , and excellent operational durability forms both cycling and chronoamperometric measurements in alkaline solution. Most impressively, this hybrid catalyst retains a mass-specific current of 440 mA mg even after 20 000 s of chronoamperometric testing, and its original activity can be regenerated via simple cyclic voltammetry cycles in clean KOH. This great catalyst durability is understood based on both CO stripping and in situ attenuated total reflection infrared experiments suggesting that the presence of Ni(OH) alleviates the poisoning of Pd nanocrystals by carbonaceous intermediates. The incorporation of Ni(OH) also markedly shifts the reaction selectivity from the originally predominant C2 pathway toward the more desirable C1 pathway, even at room temperature.

An effective strategy is developed to synthesize high‐nuclearity Cu clusters, [Cu53(RCOO)10(C≡CtBu)20Cl2H18]+ (Cu53), which is the largest CuI/Cu0 cluster reported to date. Cu powder and Ph2SiH2 are employed as the reducing agents in the synthesis. As revealed by single‐crystal diffraction, Cu53 is arranged as a four‐concentric‐shell Cu3@Cu10Cl2@Cu20@Cu20 structure, possessing an atomic arrangement of concentric M12 icosahedral and M20 dodecahedral shells which popularly occurs in Au/Ag nanoclusters. Surprisingly, Cu53 can be dissolved in diethyl ether and spin coated to form uniform nanoclusters film on organolead halide perovskite. The cluster film can subsequently be converted into high‐quality CuI film via in situ iodination at room temperature. The as‐fabricated CuI film is an excellent hole‐transport layer for fabricating highly stable CuI‐based perovskite solar cells (PSCs) with 14.3 % of efficiency.