In-situ photovoltage transients assisted catalytic study on H2O2 photoproduction over organic molecules modified carbon nitride photocatalyst

Abstract

Artificial photocatalysis holds great promise for the production of cheap and clean H2O2. Therefore, it is emerging interest to develop metal-free photocatalysts due to their adjustable band gap, wide spectral response range and cheap. Here, we demonstrated the high efficient H2O2 photoproduction of 833 μmol g−1 h−1 (18.41 μmol m-2 h−1) with terephthalic acid modified carbon nitride (PTA0.6/CN) hybrids as catalysts, which was 13.6 times (20.92 times) higher than that of pristine carbon nitride. The apparent quantum efficiency (QE) is up to 0.67 % (at λ =420 nm). Notably, with the assistance of in-situ transient photovoltage (TPV) analysis, the catalytic mechanism, catalytic kinetics and optimized reaction conditions were determined in this alluring approach. These in-situ TPV tests and analysis offered a thermodynamic-kinetic model, which showed the great capability to directly extract the half reaction rate, electron transfer number and catalytic activities without carrying out complex parallel, contrast and optimal experiments. This study not only provides a new model system for exploring photoelectric interface, thermodynamic and kinetic properties of catalysts, but also opens up opportunities for the design of next-generation high-performance photocatalysts.