Self-supporting ZnO-Cu2S nanoflower arrays heterostructure with superhydrophilic and aerophobic properties for oxygen evolution reaction

Abstract

Oxygen evolution reaction (OER) is often considered as a major bottleneck in water splitting because of its slow kinetics and limited energy conversion efficiency. Herein, we constructed ZnO-Cu2S nanoflower arrays on copper foam (CF) substrate with porous structure and high conductivity for accelerated mass transfer and electron transfer. The ZnO-Cu2S heterostructure can generate a simple electron transport pathway, optimize the water adsorption energy, and thus improve the electrochemical performance. Meanwhile, superhydrophilic and aerophobic of ZnO-Cu2S/CF is conducive to the immersion of electrolyte, and the bubbles can be quickly detached from the electrode surface. As a result, the current density of ZnO-Cu2S/CF is 20 mA·cm−2, the potential is only 1.359 V, and it is stable for 24 h. The improvement of OER performance of electrocatalyst is mainly due to the increase of active sites, the acceleration of electron transfer between electrode and electrolyte, and the synergistic effect between ZnO and Cu2S. The design concept of ZnO-Cu2S/CF with aerophobic heterostructures provides new ideas for the design and synthesis of future electrocatalysts.