Sn₃O₄ Nanoflowers/Mn_0.5Cd_0.5S Heterojunction as Piezo-photocatalyst for Hydrogen Evolution Reaction

Piezo-photocatalysis has been considered as a promising strategy for hydrogen production through the piezoelectric effect. In this work, we synthesized a series of Sn3O4/MnxCd1–xS (0 ≤ x ≤ 0.7) piezo-photocatalytic heterostructures for hydrogen evolution reaction. Mn0.5Cd0.5S (MCS) showed the uppermost hydrogen evolution rate (5.57 mmol/g/h) among all MnxCd1–xS catalysts. When simultaneously subjected to ultrasonic treatment and irradiation, the optimal Sn3O4/Mn0.5Cd0.5S (Sn3O4/MCS) composite catalyst exhibited a piezo-photocatalytic H2 evolution rate (21.46 (mmol/g)/h), which is enhanced by 3.85 times over that of pure MCS. And the fabricated catalysts possess favorable stability; after 4 cycles of experiments, the hydrogen evolution rate can still reach 19.39 mmol/g/h. The piezo-photocatalytic process, along with the construction of heterojunction, generated electric field, significantly enhancing the separation and migration of carriers, which boosted the hydrogen production rate of Sn3O4/MCS. This work offers a method for designing type-II heterojunction catalyst utilizing both mechanical and solar energy for efficient hydrogen production and shows its potential for green energy application.