Sn<sub>3</sub>O<sub>4</sub> Nanoflowers/Mn<sub>0.5</sub>Cd<sub>0.5</sub>S Heterojunction\nas Piezo-photocatalyst for Hydrogen\nEvolution Reaction

Piezo-photocatalysis has been considered as a promising\nstrategy\nfor hydrogen production through the piezoelectric effect. In this\nwork, we synthesized a series of Sn<sub>3</sub>O<sub>4</sub>/Mn<sub><i>x</i></sub>Cd<sub>1–<i>x</i></sub>S\n(0 ≤ <i>x</i> ≤ 0.7) piezo-photocatalytic\nheterostructures for hydrogen evolution reaction. Mn<sub>0.5</sub>Cd<sub>0.5</sub>S (MCS) showed the uppermost hydrogen evolution rate\n(5.57 mmol/g/h) among all Mn<sub><i>x</i></sub>Cd<sub>1–<i>x</i></sub>S catalysts. When simultaneously subjected to ultrasonic\ntreatment and irradiation, the optimal Sn<sub>3</sub>O<sub>4</sub>/Mn<sub>0.5</sub>Cd<sub>0.5</sub>S (Sn<sub>3</sub>O<sub>4</sub>/MCS)\ncomposite catalyst exhibited a piezo-photocatalytic H<sub>2</sub> evolution\nrate (21.46 (mmol/g)/h), which is enhanced by 3.85 times over that\nof pure MCS. And the fabricated catalysts possess favorable stability;\nafter 4 cycles of experiments, the hydrogen evolution rate can still\nreach 19.39 mmol/g/h. The piezo-photocatalytic process, along with\nthe construction of heterojunction, generated electric field, significantly\nenhancing the separation and migration of carriers, which boosted\nthe hydrogen production rate of Sn<sub>3</sub>O<sub>4</sub>/MCS. This\nwork offers a method for designing type-II heterojunction catalyst\nutilizing both mechanical and solar energy for efficient hydrogen\nproduction and shows its potential for green energy application.