Cost-effective catalysts for renewable hydrogen production via electrochemical water splitting: Recent advances

Hydrogen, with zero-carbon footprint, high energy density, and earth abundance, is proved as a great energy carrier for a sustainable energy scheme, which is recognized as one key solution to mitigate climate change and reduce air pollution. To achieve this goal, reducing the cost of renewable hydrogen production via electrochemical water splitting is a requisite for supporting a reliable and affordable hydrogen economy. Thus, the development of cost-effective catalysts for water electrolysis is of great significance. In this review, the recent advances in low-cost electrocatalysts for water splitting are summarized, including transition metal–based catalysts and metal-free catalysts. The emphasis is put on the catalyst design strategies and the underlying structure–performance mechanisms. The challenges and perspectives in this booming field are also presented.