Ti3+ sites on mesoporous titania enable selective photocatalytic decomposition of NO to N2 and O2 under visible light

Photocatalytic decomposition of NO to N2 and O2 represents an ideal strategy for effectively eliminating low-concentration NO. However, a notable challenge in this approach is the dual necessity of inducing efficient N-N coupling between neighboring adsorbed NO molecules and facilitating the subsequent reduction of N2O into N2. In this study, utilizing the Ti3+ self-doping method, we designed a mesoporous TiO2-x for selective photocatalytic decomposition of NO to N2 and O2. Under visible-light irradiation, the mp-TiO2-x enriched with Ti3+ sites efficiently decomposed 81.8% of NO to an almost equimolar amount of N2 and O2, achieving the N2 selectivity of 93.8%. The crucial roles of Ti3+ sites were confirmed in catalyzing the N-N coupling of adjacent adsorbed NO molecules and promoting the conversion of N2O into N2. The collaborative actions of electron and hole reactions empower the selective and durable photocatalytic breakdown of NO into N2 and O2 under visible light.