Phosphomolybdic acid-modified polyaniline nanowires with abundant acidic sites for efficient photocatalytic reduction of nitrate to nitrogen in water

Although polymeric conductive polyaniline (PANI) is an effective material for catalytic nitrate reduction in water, its catalytic efficiency is limited. Here, we report that phosphomolybdic (PMoA) acid-modified PANI nanowires exhibit superior activity in the catalytic reduction of nitrate to harmless N₂. Excellent catalytic efficiency is attributed to the construction of Z-scheme heterojunctions and the combined contribution of chemical-photocatalytic reduction. Pyridine infrared analysis confirms that the introduction of PMoA adds an abundance of acidic sites to PANI, which explains the extraordinary N₂ selectivity. Additionally, DFT calculations are used to determine the band structures and surface electron transfer pathways of the two materials. Impressively, the effectiveness of catalytic nitrate reduction under various conditions is evaluated together with the practicality of PMoA-PANI by simulating saltwater. This work sheds new light on the mechanism of polymer for efficient reduction of nitrate and develops innovative technology for the remediation of practical wastewater.