Green ammonia synthesis coupled with cellulose valorization over oxygen vacancy-enriched MoO3-x photocatalysts

MoO 3 has been recognized as a potential photocatalyst for photocatalytic ammonia synthesis from N 2 in sacrificial reagent assisted half-reaction system, but is lacking in both sluggish kinetics of N 2 reduction due to the absence of efficient active sites and low practicality originated from high cost sacrificial reagent. Herein, aiming to simultaneously bolster N 2 reduction reaction kinetics and improve practicality, oxygen vacancy-enriched MoO 3-x nanoplates was prepared as photocatalyst for green photocatalytic ammonia synthesis by using abundant cellulose in nature as the sacrificial reagent. Under light irradiation, MoO 3-x photocatalysts simultaneously achieve ammonia production and the conversion of cellulose into high-value chemicals, and the highest NH 3 generation achieves 21.4 μmol g -1 ·h -1 under 300 W Xe lamp irradiation in cellulose solution. The excellent photocatalytic activity of MoO 3-x can be ascribed to the positive role of oxygen vacancy, which provides abundant active sites for ammonia synthesis. Meanwhile, the oxygen vacancy induces the generation of Mo 5+ in MoO 3-x , which inhibits the reduction of MoO 3-x to water-soluble H x MoO 3 , resulting in the high structure stability of MoO 3-x . This work provides new insight for the development of defect-engineered photocatalysts for green ammonia synthesis coupled with sustainable cellulose valorization.