Insight on the optimized electronic structure of carbon nitride on ultrafast water treatment via photocatalytic activation of ferrate.

Ferrate (Fe(VI)) is a widely used water purifier and is easily affected by external factors. Given that the actual water environment conditions are complicated, this study designed an oxygen-doped carbon nitride (CNO) with rich electron sites to explore whether direct electron transfer promotes the degradation efficiency of Fe(VI) for pollutants under visible light. For comparison, we also prepared phosphorus-doped carbon nitride (CNP), which has electron-deficient sites and indirect electron transfer. In the CNO/Fe(VI)/light system, not only more high-valent iron and reactive oxygen species were generated, but also the pollutant degradation rate, reaction kinetics, and electron yield were significantly better than those of the CNP and CN systems, verifying the superiority of direct electron transfer. In addition, CNO showed excellent performance in both actual solar photocatalysis and continuous flow experiments. Therefore, the photocatalysis/direct electron transfer mechanism proposed provides an innovative strategy for improving the application potential of Fe(VI) in the field of pollution control and its industrialization application.