In-situ construction of S-scheme SnSe2/Se heterojunction photocathode with enhanced photoelectrochemical performance by a facile one-step CVD process

Abstract

Selenium, as one of the first photovoltaic materials used, shows outstanding light absorption, high carrier mobility, long carrier lifetime, and easy preparation, which currently has great potential but few reported in the field of solar hydrogen production. At the same time, Se semiconductor also have high photogenerated carrier recombination rates. In this work, SnSe2/Se S-scheme heterojunction was successfully constructed by a facile one-step CVD method to reduce the photogenerated electron-hole pairs recombination and improve the utilization of visible light. The photocurrent density of the monomeric Se photocathode was − 1.2 mA cm−2 at 0 VRHE under simulated single insolation conditions, and the photocurrent density of the SnSe2/Se photocathode (− 3.7 mA cm−2 at 0 VRHE) was nearly three times higher than that of the monomeric Se. This research introduces S-scheme heterojunction to improve Se photocathode PEC performance in the field of solar hydrogen production and offers new prospects for the preparation of Se based composite photoelectrode with high efficiency by a facile method.