Robust Cu₂O/CuS Heterostructured Cu₄₀ Nanoclusters for Electrocatalytic Hydrogen Evolution

Metal oxide/metal chalcogenide heterostructure materials have garnered intensive attention in both fundamental research and practical applications, particularly in the field of catalysis. For example, the Cu2O/CuS heterostructures have found wide applications in electrocatalysis and photoelectrocatalysis. Despite their wide-ranging applications, the atomic-level insight into the interfacial structures of Cu2O/CuS heterostructure materials and the effect of such interface on catalysis has remained a longstanding challenge. Herein, we present a comprehensive illustration of Cu2O/CuS heterostructures through the complete structural determination of an atomically precise copper nanocluster, Cu40O8(tBuS)24 (tBuSH is 2-methyl-2-propanethiol) whose structure describes the stabilization of Cu4O tetrahedra by −S–Cu–S– units. Notably, the cluster has been prepared in one pot under ambient conditions and exhibits exceptional stability when subjected to heat and highly concentrated acid (1 M HCl) or base (1 M KOH), respectively. Importantly, the cluster exhibits outstanding activity in the electrocatalytic hydrogen evolution reaction (HER), surpassing the performance of most reported copper nanoclusters with an overpotential of 90 mV at 10 mA/cm2. Both the experimental and theoretical investigations suggest that the heterostructures of the cluster play a pivotal role in enhancing its electrocatalytic HER activity. This work not only provides crucial insights into the long-pursued interfacial structures of Cu2O/CuS heterostructure materials but also paves the way for the fabrication of atomically precise metal nanoclusters featuring metal oxide/metal chalcogenide heterostructures.