Atomically dispersed scandium Lewis acid sites on carbon nitride for efficient photocatalytic hydrogen peroxide production

Abstract

Photocatalytic reduction of oxygen represents a promising way to produce hydrogen peroxide (H2O2) owing to the merits of energy saving and environmental benignancy. However, the low activity and selectivity of the photocatalyst impede its practical application. Herein, following the principle of metal ion-coupled electron transfer, we have fabricated a class of graphitic carbon nitride (g-C3N4) decorated with atomically dispersed scandium Lewis acid (Sc/H-CN) using a facile impregnation-calcination method. The as-synthesized Sc/H-CN exhibits excellent H2O2 production performance with a rate of 55 µmol h−1, which is 6.2 times over bare CN. The improved performance is ascribed to the enhancement of O2 electron-accepting capability through binding of Sc Lewis acid sites with intermediate ·O2−, inhibiting its reverse reaction. Moreover, density function theory (DFT) calculation and Koutecky-Levich analysis show that the reduced O−O bond breakage is responsible for the high selectivity in the production of H2O2. This work provides a new strategy for the design of photocatalysts equipped with appropriate active sites towards various applications.