Catalytic origin and universal descriptors of heteroatom-doped photocatalysts for solar fuel production

Solar fuels produced from sunlight via photocatalytic water splitting and artificial photosynthesis represent one of the most promising clean energy sources. Various semiconductors, including graphitic carbon nitride (g-C3N4) and transition metal oxides, have been considered as photocatalysts for the fuel production, but there lacks of the design principles for rapid screening of the best photocatalysts from numerous candidate materials. Here, we demonstrate, for the first time, a universal guiding principle that governs the photocatalytic activities of p-orbital element-doped C3N4-based photocatalysts for photocatalytic water splitting, which is also applicable to other doped semiconductors including ZnO and TiO2 for water splitting and carbon dioxide reduction. An activity indictor is introduced to determine the efficiency of non-metal-doped semiconductor photocatalysts for the solar fuel production. These predictions are supported by experimental results. This generalized principle could guide a broad photochemical production of solar fuels including hydrogen, hydrocarbon, and other green chemicals.