Construction of a wide-spectrum-driven V-N-g-C3N4/Cu-2(OH)(2)CO3 heterojunction catalyst from VIS to NIR light via the in situ self-sacrificial method: the effect of oxygen on the N-2 photofixation ability

摘要

In this work, an N vacancy-doped g-C3N4/Cu-2(OH)(2)CO3 (V-N-GCN/CuCOH) heterojunction catalyst with superior wide-spectrum-driven (from VIS to NIR) N-2 photofixation ability was synthesized via the in situ self-sacrificial method. The characterization results show that the charge transfer between g-C3N4 and Cu-2(OH)(2)CO3 follows the "Z-scheme" mechanism. The addition of oxygen has a significant effect on the nitrogen photofixation performance of the as-prepared catalyst using methanol as a hole scavenger. Under the atmosphere of 50% O-2 and 50% N-2, the as-prepared V-N-GCN/CuCOH heterojunction catalyst displays an ammonium ion production rate as high as 14 mg L-1 h(-1) g(cat)(-1), which is 2.5 times higher than that under a pure nitrogen atmosphere. A "two-path" ammonia production mechanism is proposed in this work.