Addressing the stability challenge of photo(electro)catalysts towards solar water splitting

The efficiency and stability of photo(electro)catalytic devices are the main criteria towards practical solar fuel production. The efficiency of photocatalysts/photoelectrodes has been intensively pursued and significant progress has been achieved over the past decades. However, the development of durable photocatalysts/photoelectrodes remains one of the biggest challenges for solar fuel production. Moreover, the lack of a feasible and reliable appraisal procedure makes it difficult to evaluate the durability of photocatalysts/photoelectrodes. Herein, a systematic process is proposed for the stability evaluation of photocatalysts/photoelectrodes. A standard operational condition should be used for the stability assessment and the stability results should be reported with the run time, operational stability, and material stability. A widely adopted standardisation for stability assessment will benefit the reliable comparison of results from different laboratories. Furthermore, the deactivation of photo(electro)catalysts is defined as a 50% decrease in productivity. The purpose of the stability assessment should aim to figure out the deactivation mechanisms of photo(electro)catalysts. A deep understanding of the deactivation mechanisms is essential for the design and development of efficient and stable photocatalysts/photoelectrodes. This work will provide insights into the stability assessment of photo(electro)catalysts and advance practical solar fuel production. In this perspective, we emphasise the importance of stability evaluation in the development of photo(electro)catalysts and related devices towards practical solar water splitting.