Interface, vacancy, and morphology engineering synergistically improve In2S3@Cu2S electrocatalytic performance for pH-universal HER

Abstract

Tremendous challenges still lie ahead in synergistically improving the pH-universal HER performance of noble metal-free electrocatalysts by multiple modification strategies. Herein, In₂S₃@Cu₂S nanorod heterostructure arrays were in situ grown on a copper foam (In₂S₃@Cu₂S NAs/CF) through the traditional solvothermal method, followed by calcination, hence constructing an efficient electrocatalyst for pH-universal HER. The optimal In₂S₃@Cu₂S NAs/CF-2 electrocatalyst requires overpotentials of only 42 mV, 78 mV, and 61 mV to drive a current density of 10 mA cm⁻² in acidic, neutral, and alkaline media, respectively. Furthermore, In₂S₃@Cu₂S NAs/CF-2 also exhibits salient stability after 20 000 cycles and 150 h long-term use. The outstanding electrocatalytic performance is mainly attributed to the formation of a strong built-in electric field on the heterostructure interface, the increase in the accessible active sites, optimization of the electronic structure derived from abundant S vacancies, as well as the enhancement of the electrochemically active area owing to the unique vertically grown nanoarray structure. This work will pave a new avenue toward multiple modification strategies to synergistically improve electrocatalytic hydrogen production in a wide pH range.