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

Abstract

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.