Promoting Solar Hydrogen Production of Silicon Heterojunction Photocathode Via Constructing Solution‐Processed Ni3S2/Cu/Ce(OH)3 Nanoarchitecture

Photoelectrochemical (PEC) water splitting using photovoltaic cell is considered an ideal path for hydrogen production. However, its application is limited by the low efficiency of the photoelectrode surface. Herein, we successfully fabricated efficient composite hydrogen evolution reaction (HER) catalysts onto silicon heterojunction (SHJ) solar cell via solution‐processed methods under mild conditions. The fabricated nanoheterostructured HER catalysts consist of crystalline Ni 3 S 2 , Cu, and Ce(OH) 3 , which display excellent HER performance due to the synergistic effect of the constituted components. As a result, the optimized photocathode achieves a high photocurrent of −37.8 mA cm −2 at 0 V vs. Reversible hydrogen electrode and an applied bias photon‐to‐current efficiency (ABPE) of 8.5 ± 0.1% under simulated AM 1.5G one‐sun illumination and more than 120 h of continuous water splitting. This study offers novel insights into designing economical large‐scale PEC devices.