Facile preparation and enhanced photocatalytic hydrogen evolution of cation-exchanged zeolite LTA supported TiO2 photocatalysts

Abstract

Photocatalytic hydrogen evolution (PHE) is an attractive green way to produce clean energy. Zeolite-supported titanium dioxide (TiO2) offers a cost-efficient pathway to prepare an efficient and recyclable photocatalyst for PHE. As known, zeolite has an excellent cation exchange capacity, and the exchangeable cations show considerable influence on its properties. However, the effect of exchangeable cations within zeolite-supported TiO2 photocatalysts on their PHE activity remains unclear. Here, we prepared a series of zeolite LTA-supported TiO2 photocatalysts (TXA, X = Na, K, Ca) with various cations (Na+, K+, Ca2+) inside the zeolite and investigated the effect of cations on their PHE activity. The results demonstrated that all TXA photocatalysts exhibit significantly enhanced PHE activity, and TCaA shows the highest hydrogen evolution rate, which is 3.84 times higher than that of P25. According to experimental results, TCaA possesses a higher solid-acid concentration and a larger surface area, which provides more proton sources and active sites for PHE, facilitates charge separation, and reduces photogenerated electron-hole pair recombination. We believe this work will offer a new exploration strategy for regulating the PHE performance of zeolite-supported TiO2-based photocatalysts and shed new light on the rational design of cost-efficient PHE catalysts.