Electro-deposited copper nanoclusters on leaf-shaped cobalt phosphide for boosting hydrogen evolution reaction

•The in-situ preparation methods for Cu nanocluster and leaf-shaped Co2P are used.•The deposition of Cu nanocluster improves the surface electronic property of Co2P.•The composite Co2P@Cu electrocatalyst has better HER performance compared to Co2P.•The promoted Schottky effect between Cu nanoclusters and Co2P is determined. [Display omitted] HER mechanism and stability of the leaf-shaped cobalt phosphide decorated with electro-deposited copper nanoclusters. Exploring structural regulation of transition metal phosphides (TMPs) by incorporating suitable foreign components to increase hydrogen evolution reaction (HER) performance presents considerable development for electrocatalytic water-splitting technology. Herein, we reported an original construction strategy of thin-leaf-shaped cobalt phosphide coupled with copper nanoclusters supported on nickel foam (NF) for HER. A simple electrochemical deposition technique is used to obtain the interface-engineered Co2P@Cu nanostructure. The resultant nanocomposite with a vertically staggered structure shows the enhanced electrochemical characteristics derived from the Schottky junction at the interface between Co2P and Cu, which has a large of active sites and low charge-transfer resistance. The Schottky effect promotes charge distribution, accelerates adsorption of hydrogen intermediates, and facilitates electron transfer in the Co2P. As a result, the Co2P@Cu composite drives the current densities of 10 and 100 mA cm−2 for the alkaline HER to reach the lower overpotentials of 99.7 and 303.2 mV, respectively, and a smaller Tafel slope of 48.8 mV dec−1 compared to the bare Co2P electrocatalyst. Moreover, the proposed electrode exhibits good HER durability with almost no loss of Cu based on 2000 cycles of cyclic voltammetry sweeps and 24 h of chronoamperometry test. This work offers a perspective for the additive engineering of non-noble metals to metal phosphides toward efficient HER.