Atomic-level investigation on significance of photoreduced Pt nanoparticles over g-C3N4/bimetallic oxide composites

Designing an effective photocatalyst for solar-to-chemical fuel conversion presents significant challenges. Herein, g-C3N4 nanotubes/CuCo2O4 (CN-NT-CCO) composites decorated with platinum nanoparticles (Pt NPs) were successfully synthesized by chemical and photochemical reductions. The size distribution and location of Pt NPs on the surface of CN-NT-CCO composites were directly observed by TEM. Extended X-ray absorption fine structure (EXAFS) spectra of Pt L3-edge for the above composite confirmed establishment of Pt-N bonds at an atomic distance of 2.09 & ANGS; in the photoreduced Pt-bearing composite, which was shorter than in chemically reduced Pt-bearing composites. This proved the stronger interaction of photoreduced Pt NPs with the CN-NT-CCO composite than chemical reduced one. The H-2 evolution performance of the photoreduced (PR) Pt@CN-NT-CCO (2079 & mu;mol h(-1) g(-1)) was greater than that of the chemically reduced (CR) Pt@CN-NT-CCO composite (1481 & mu;mol h(-1) g(-1)). The abundance of catalytically active sites and transfer of electrons from CN-NT to the Pt NPs to participate in the hydrogen evolution are the primary reasons for the improved performance. Furthermore, electrochemical investigations and band edge locations validated the presence of a Z-scheme heterojunction at the Pt@CN-NT-CCO interface. This work offers unique perspectives on the structure and interface design at the atomic level to fabricate high-performance heterojunction photocatalysts.

Automated summary

Pt-decorated g-C3N4 nanotubes/CuCo2O4 composites were successfully synthesized by chemical and photochemical reductions. The photoreduced Pt@CN-NT-CCO showed enhanced H-2 evolution performance compared to the chemically reduced Pt@CN-NT-CCO composite due to the abundance of active sites and efficient electron transfer. This study provides insights into atomic-level structure and interface design for high-performance heterojunction photocatalysts.