Construction of a Highly-Dispersed and Efficient Charge-Separation–Transferring Interface by Oxidatively-Bonding Rh in Cu2O Surface for Dye Photodegradation

Deliberately modulating the surface structure of oxide semiconductor materials was crucial to improve their photoelectronic conversion performance. Here, surface engineering of a Cu2O-based semiconductor (cubic particles in an average size of 300 nm) by redox embedding Rh with RhCl63– was attempted to get a series of Rh–Cu2O catalysts, and their photocatalytic properties were typically surveyed from dye (methyl orange, MO) photodegradation. With comprehensive characterizations, it was demonstrated that the highly dispersed and tightly integrated Rh–Cu2O interface, featuring oxidatively bonded Rh in surface layers of the Cu2O substrate, was well constructed by adjusting Rh loading from 0.04 to 0.38 wt %, exhibiting an obvious enhancement in photocatalytic performance for MO degradation compared to bare Cu2O. The measurements from photoproduction of H2, photocurrent, electrochemical impedance, and scavengers-present tests further illuminated that the Rh species bonded on the Cu2O surface in an electron-deficiency state and greatly contributed to not only improving separation efficiency of photogenerated electron/hole pairs, but also lowering the resistance to speed charge transferring along the Rh–Cu2O interface, resulting in the enhanced photocatalytic performance of Rh–Cu2O catalysts. In addition, the photocatalytic principle of Rh–Cu2O catalysts for dye degradation was also discussed. These results indicated that oxidatively bonded metal species in surface layers of Cu2O was feasible for getting an efficient charge-separation–transferring M–Cu2O interface to improve the photoelectronic conversion performance, which could be referred to as a notable system to directly engineer a semiconductor surface for advanced photoenergy applications.