In-situ polymerization of polyaniline modified by phosphotungstic acid on the surface of hollow carbon for two-way efficient reduction of nitrate in water

Catalytic reduction of nitrate to harmless nitrogen is a significant and promising green environmental protection technology. In this paper, the reduction of nitrate by two pathways is realized without light (Reaction I) and under light (Reaction II) conditions by wrapping polyaniline modified by phosphotungstic acid on the hollow carbon surface (H₃PW₁₂O₄₀-PANI-C, HPC). Modified PANI chain and Z-scheme heterojunction make the hollow carbon surface form an interfacial electron transport network, which not only shortens electron migration distance but also promotes the carrier separation and transfer. HPC catalysts concentrate the advantages of adsorption, high conductivity and abundant catalytic sites to promote the reduction efficiency. Satisfied nitrogen generation and fewer hole scavengers using make HPC catalysts more practical. This work emphasizes the rapid conduction of interfacial electrons and the effect of catalytic sites on nitrate removal, which provides new guidance for the treatment of pollutants in water.