Internal Electric Field Assisted Photocatalytic Generation of Hydrogen Peroxide over BiOCl with HCOOH

Abstract

Hydrogen peroxide (H₂O₂) is a superb, clean, and versatile reagent. However, large-scale production of H₂O₂ is manufactured through nongreen methods that motivate people to develop more efficient and green technologies as alternatives. As a novel and green technology used for H₂O₂ generation, the efficiency of photocatalysis is still far from satisfactory. Here, we demonstrate a novel and efficient path of the generation of H₂O₂ in BiOCl photocatalysis but not the direct electron reduction of O₂ or hole oxidation of OH^– to H₂O₂. Super high production (685 μmol/h) of H₂O₂ by the addition of HCOOH as the hole shuttle was realized over BiOCl nanoplates. In this photocatalytic system, the BiOCl supplied abundant photoinduced holes to initiate HCOO^• radical. The HCOO^• further reacts with OH^– to •OH which is proven to be the source of the H₂O₂. Apart from HCOOH, O₂ also played important roles. The O₂ not only promoted the reaction through the cycle between Bi³⁺ and Bi, which decreased the combination of carriers, but also avoided the carbonation of surfaces, thus achieving the high production of H₂O₂ (1020 μmol/h). In this work, we shed light on a deep understanding of the photocatalytic evolution of H₂O₂ in a novel perspective and achieve high production