Plasma Engraved Bi.sub.2MoO.sub.6 for Enhanced Photocatalytic Nitrate Reduction Reaction

Photocatalytic nitrate removal to produce recyclable netrogen (N.sub.2) without using chemical reductants is regarded as an environmentally friendly and effective technology for denitrification. However, the sluggish cathode reaction kinetics severely hampered the efficiency of nitrate reduction reaction (NO.sub.3RR). Developing high performance photocatalyst is highly pursued for boosting NO.sub.3RR. In this study, Bi.sub.2MoO.sub.6 nanosheets with massive oxygen vacancies are fabricated through hydrothermal reaction and subsequent plasma modification. Maximal nitrate conversion yield of 38% with the high N.sub.2 selectivity of 80.0% is achieved for photocatalytic NO.sub.3RR. The underlying photocatalytic mechanism is systemically investigated through comprehensive approaches. The enhanced nitrate conversion efficiency is mainly attributed to the synergistic effect between deliberately generated oxygen vacancies and Mo active sites, capturing O and N atoms of nitrate, respectively, thus promoting the adsorption of nitrate and cleavage of N-O bond. Furthermore, the H "repulsion" effect of Bi efficiently suppresses hydrogenation reaction, resulting in greatly enhanced N.sub.2 selectivity.