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

Abstract

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 Å 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 H2 evolution performance of the photoreduced (PR) Pt@CN‐NT‐CCO (2079 μmol h−1 g−1) was greater than that of the chemically reduced (CR) Pt@CN‐NT‐CCO composite (1481 μmol 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.

Tailoring Interfacial Physicochemical Properties in Cu2O-TiO2@rGO Heterojunction: Insights from EXAFS and Electron Trap Distribution Analysis

“…The photocurrent plots of the as-synthesized TNF, Cu 2 O, CTNF, and CTNF@rGO-3% composite are displayed in Figure c. The separation efficacy of photogenerated electrons and holes is proportional to the photocurrent density of the photocatalysts . After exposure to visible light, the photocurrent of the photocatalysts grew dramatically and stabilized at a particular level, but it rapidly decreased when the illumination was removed.…”

“…The separation efficacy of photogenerated electrons and holes is proportional to the photocurrent density of the photocatalysts. 51 After being exposed to visible light, the photocurrent of the photocatalysts grew dramatically and stabilized at a particular level, but it rapidly decreased when the illumination was removed. Photocurrent densities of 2.5 µAcm -2 and 5 µAcm -2 were achieved for Cu2O and TNF, respectively, illustrating the weak electron and hole separation capabilities in pristine semiconductors.…”