Abstract

Electrocatalysis and photocatalysis for clean hydrogen (H₂) production have been widely regarded as promising technologies to counter the increasing energy crisis. However, developing applicable catalysts with high H₂ production performance still poses a challenge.

In this review, state-of-art nanoscale electrocatalysts for water electrolysis and photocatalysts for water splitting, tailored for different reaction environments including acidic electrolyte, alkaline electrolyte, pure water, seawater, and hydrohalic acids are systematically presented.

In particular, modification approaches such as doping, morphology control, heterojunction/​homojunction construction, as well as the integration of cocatalyst and single atom for efficient charge transfer and separation are examined.

Furthermore, the unique properties of these upgraded catalysts and the mechanisms of promoted H₂ production are also analyzed by elucidating charge carrier dynamics revealed by photophysical and photoelectrochemical characterization methods.

Finally, perspectives and outlooks on future developments of H₂ production using advanced electrocatalysts and photocatalysts are proposed.