Highly efficient Bi2Fe4O9-ZnIn2S4 Z-scheme heterojunction for piezo-photocatalytic overall water splitting under near-infrared light up to 1200 nm

Photocatalytic overall water splitting is considered as a sustainable and appealing strategy to solve the issues of energy supply and conversion. However, a critical hurdle to applying photocatalytic overall water splitting is the restricted light absorption and sluggish mobility of light-induced charge carriers in catalysts. Herein, a near-infrared light-responsive Bi2Fe4O9-ZnIn2S4 Z-scheme piezoelectric photocatalyst with a Fe-S bonded interface is constructed. This ingenious design synergistically utilizes the advantages of the Z-scheme, strong coupling interfaces, and piezoelectric field. The Bi2Fe4O9-ZnIn2S4 Z-scheme heterojunction significantly suppresses photogenerated carriers' recombine and extends photocatalytic response to the infrared light region, achieving highly efficient piezo-photocatalytic activity. Consequently, the optimized Bi2Fe4O9-ZnIn2S4 heterojunction displays an unprecedented piezo-photocatalytic H2 and O2 generation rate of 1862 and 927 μmol h−1 g−1 under sunlight illumination. This rate is approximately 4.9 and 10.0 times greater than that of photocatalysis and piezocatalysis alone. This study lays novel groundwork for developing future heterojunctions for photocatalytic water splitting.