MOF-Derived C/N-CeO2/Bi2Te3 Heterostructure for Enhanced Photocatalytic Two-Electron Oxygen Reduction Reaction

Abstract

Photocatalytic H2O2 production from the oxygen reduction reaction (ORR) has emerged as a sustainable and green approach to address the global energy crisis and environmental challenges. However, its practical application is still limited by sluggish reaction kinetics and fast recombination of photogenerated excitons. Yet, these limitations can be effectively mitigated by rational photocatalyst design strategies that enhance charge separation and accelerate ORR kinetics. Herein, we designed a nanocomposite C/N-CeO2/Bi2Te3 (CBT) by a two-step solvothermal and calcination synthesis process of Ce-MOF-derived C/N-CeO2 combined with in situ growth of Bi2Te3 to obtain a composite of C/N-CeO2 nanorods with Bi2Te3 nanoflowers. The strong interfacial interaction between the two pure materials is substantiated by using various microscopic, electrochemical, and spectroscopic characterizations. The photocatalytic H2O2 production of 5 wt % Bi2Te3-loaded C/N-CeO2 (CBT-5) sample achieved 1889 μmol g–1 h–1 under light illumination, with an apparent quantum yield (AQY) of 4.23% at a wavelength of 340 nm. The superior photocatalytic performance of CBT-5, reflected by its high TOF value of 0.325 h–1, can be attributed to the unique characteristics of Bi2Te3 as a cocatalyst; its topological insulator nature provides highly conductive surface channels that promote rapid electron transport, effectively suppress the recombination of photogenerated charge carriers, and thereby enhance the photocatalytic two-electron ORR for H2O2 production. This work can inspire exploration of the construction of MOF-derived, oxide-based, defect-rich hybrid structures for photocatalytic sustainable energy applications.