Fabrication strategies for high-performance unbiased PEC water splitting cells

Abstract

Photoelectrochemistry (PEC) is an effective method for harvesting renewable hydrogen directly from water utilizing sunlight. Recent studies have shown that it is possible to achieve high solar-to-hydrogen (STH) using tandem-structured PEC cells; however, the low onset potential and stability of photoelectrodes have become major obstacles to the development of practical tandem cells. This review introduces the research status of PEC water splitting from the aspects of photocatalysis types, photoelectrode types and performance evaluation standards. In addition, the research progress of tandem PEC is reviewed, and the key issues of device optimization and strategies for improving STH efficiency are discussed in terms of crystallinity, structure matching and charge extraction efficiency. It is hoped that this review will provide useful guidance for the future development of stable and efficient water separation unbiased PEC cells.