Boosting Photocatalytic Nitrogen Reduction Reaction by Jahn-Teller Effect.

Compared with traditional the Haber-Bosch process, photocatalytic ammonia production has attracted a considerable attention due to its advantages of low energy consumption and sustainability. In this work, we mainly study the photocatalytic nitrogen reduction reaction (NRR) on MoO3.0.55H2O and & alpha;-MoO3. Structure analysis shows that compared to & alpha;-MoO6, the [MoO6] octahedrons in MoO3.0.55H2O obviously distort (JahnTeller distortion), leading to the formation of Lewis acid active sites that favors the adsorption and activation of N2. X-ray photoelectron spectroscopy (XPS) further confirms the formation of more Mo5+ as Lewis acid active sites in MoO3.0.55H2O. Transient photocurrent, photoluminescence and electrochemical impedance spectra (EIS) confirmed that MoO3.0.55H2O has a higher charge separation and transfer efficiency than & alpha;-MoO3. Density functional theory (DFT) calculation further confirmed that the N2 adsorption on MoO3.0.55H2O is more favorable thermodynamically than that on & alpha;-MoO3. As a result, under visible light irradiation (A & GE; 400 nm) for 60 min, an ammonia production rate of 88.6 & mu;mol.gcat-1 was achieved on MoO3.0.55H2O, which is about 4.6 times higher than that on & alpha;-MoO3. In comparison to other photocatalysts, MoO3.0.55H2O exhibits an excellent photocatalytic NRR activity under visible light irradiation without using sacrificial agent. This work offers a new fundamental understanding to photocatalytic NRR from the viewpoint of crystal fine structure, which benefits designing efficient photocatalysts.