Mn-doped CdS/Cu2O: An S-scheme heterojunction for photocatalytic hydrogen production

This study aimed to regulate the band structure and enhance the reduction ability of CdS by substituting it with Mn 2+ . Subsequently, this nano MnCdS solid solution was anchored on the surface of truncated octahedral Cu 2 O through a simple hydrothermal process, forming an S-scheme heterojunction at the interface between MnCdS and Cu 2 O. Equilibrating the Fermi level at the MnCdS/Cu 2 O heterojunction led to spontaneous diffusion of electrons in MnCdS to Cu 2 O, generating an internal electric field that drove the recombination of electrons in the conduction band (CB) of Cu 2 O and holes in the valence band (VB) of MnCdS. Consequently, this process preserved the powerful photogenerated electrons in the CB of MnCdS, facilitating robust photocatalytic hydrogen evolution . The MnCdS/Cu 2 O exhibited a photocatalytic hydrogen evolution rate of 66.3 mmol g −1 h −1 , which was 3.4- and 54.3-times higher than that of MnCdS (19.4 mmol g −1 h −1 ) and Cu 2 O (1.2 mmol g −1 h −1 ), respectively. This study elucidates advanced S-scheme heterojunction catalyst architectures for photocatalytic hydrogen production.