Preparation of Z-Type Co2SnO4/Mn0.5Cd0.5S Heterojunction for Efficient Piezo-Photocatalytic Hydrogen Production

Abstract

Although conversion of solar-energy for catalytic water splitting into H₂ is promising technology, the sluggish charge separation in photocatalytic process severely restricts the activity. Combining the piezoelectric effect of piezoelectric materials with the load cocatalyst strategy can effectively modulate the transport behavior of carriers. Herein, a novel and efficient Co₂SnO₄ cocatalyst is loaded onto Mn_xCd_1-xS (x = 0.2, 0.3, 0.4, 0.5, 0.6, 0.7) piezoelectric material to form a heterostructure for piezo-photocatalytic hydrogen evolution. To the best of our knowledge, Co₂SnO₄ has not been reported as a cocatalyst in the field of piezoelectric photocatalysis. The 7% Co₂SnO₄/Mn_0.5Cd_0.5S (CSO/MCS) exhibits excellent piezoelectric-photocatalytic hydrogen production rate (29.86 mmol/g/h) under the condition of light coupling ultrasound, which is significantly superior to piezoelectric catalysis (128.35 μmol/g/h) and photocatalysis (9.25 mmol/g/h). The built-in electric field in Mn_0.5Cd_0.5S piezo-photocatalyst and the Z-type heterojunction made up of the tight connection of Co₂SnO₄ and Mn_0.5Cd_0.5S both promote the carrier separation efficiency, thereby improving the catalytic reaction performance. This work manifests a promising approach to design heterojunction catalysts for efficient renewable fuel production by capturing solar and mechanical energy.