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

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 O-2 or hole oxidation of OH- to H2O2. Super high production (685 mu mol/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 center dot radical. The HCOO center dot further reacts with OH- to center dot OH which is proven to be the source of the H2O2. Apart from HCOOH, O-2 also played important roles. The O-2 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 mu mol/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.