Rational design of carbon nitride for remarkable photocatalytic H2O2 production

Photocatalytic oxygen reduction reaction (ORR) on graphitic carbon nitride offers a sustainable route to produce H2O2. However, the current solar-to-H2O2 conversion efficiency is still limited by the high overpotential of 2e-ORR process and in situ H2O2 decomposition. Here, we aim to overcome these challenges by introducing the heteroatomic oxygen and cyano group. Density functional theory (DFT) study reveals that oxygen doping at the pristine position of graphitic nitrogen significantly contributes to reducing the overpotential for H2O2 formation. The introduced cyano group coupled with amino nitrogen at the edge of crystalline nanosheets synergistically interacts with doped oxygen to further boost H2O2 production and also efficiently inhibits H2O2 decomposition. As a result, visible light-driven H2O2 production at 5.57 mM/h is achieved along with selective counterpart oxidation of isopropanol to acetone at 100% selectivity. A rigorous process model combined with a techno-economic analysis (TEA) provides guidance for the development of an economically feasible photocatalytic H2O2 production process.