Inhibition of superoxide radical diffusion by Van der Waals forces for boosting photocatalytic H2O2 production

The conversion of superoxide radical (& BULL;O2 ) to hydrogen peroxide (H2O2) is critical in the photocatalytic for-mation of H2O2 via the sequential two-step single-electron oxygen reduction mechanism. Providing a high concentration of & BULL;O2  is an effective approach to promoting this process in terms of chemical kinetics. It is, however, extremely challenging to implement this idea in the photocatalytic solution due to the limited lifespan of & BULL;O2 . To this end, a concept about local & BULL;O2  enrichment catalyst surface was proposed in this study and achieved in an innovative PSI/C3N4 photocatalyst. The results of theoretical calculations and temperature-dependent photocatalytic studies indicate that PSI on the C3N4 surface can serve as a diffusion buffer for & BULL;O2 , capturing them through Van der Waals interactions and separating them by energy perturbations. As a result, a local enrichment of & BULL;O2  was established on the PSI/C3N4 surface during photocatalysis, strengthening the photocatalytic conversion of & BULL;O2  to H2O2, thus allowing the PSI/C3N4-4 photocatalyst to produce H2O2 at a rate of approximately 2.4 and 2.65 times greater than pure C3N4 under visible light and LED irradiation, respectively. This study presents a promising strategy for enhancing photocatalytic H2O2 production efficiency by selectively enriching & BULL;O2  on the catalyst surface.

Automated summary

In this study, a concept of locally enriching superoxide radicals (& BULL;O2 ) on the PSI/C3N4 photocatalyst surface was proposed and achieved. Theoretical calculations and temperature-dependent photocatalytic studies showed that PSI on the C3N4 surface can act as a diffusion buffer for & BULL;O2 , capturing them through Van der Waals interactions and separating them by energy perturbations. As a result, a local enrichment of & BULL;O2  was established on the PSI/C3N4 surface during photocatalysis, leading to enhanced conversion of & BULL;O2  to H2O2. The PSI/C3N4-4 photocatalyst produced H2O2 at a rate approximately 2.4 and 2.65 times higher than pure C3N4 under visible light and LED irradiation, respectively. This study presents a promising strategy for enhancing photocatalytic H2O2 production efficiency by selectively enriching & BULL;O2  on the catalyst surface.