Transition metal modified 3DOM WO3 with activated N N bond triggering high-efficiency nitrogen photoreduction

Abstract

Photocatalytic nitrogen fixation is a promising green strategy for ammonia synthesis, yet the high activation energy for nitrogen is the significant limitation to its practical application. Herein, a novel Fe-doped WO3 photocatalyst with three dimensional macroporous (3DOM) structure was designed and prepared. This special photocatalyst not only provides effective adsorption active sites to enhance the chemisorption and activation of N2, but also promotes the charge separation and transfer from catalyst to nitrogen. As a result, the optimized 5% Fe-3DOM WO3 sample achieves excellent ammonia production rate of 60 μmol g−1h−1, ∼30 times higher than that of pure 3DOM WO3. The in-situ DRIFTS results show the existence of several intermediates containing NH bonds during nitrogen reduction. Meanwhile, the density functional theory calculation results show that the presence of Fe promotes the adsorption and activation of nitrogen, and the reaction pathway is biased towards the alternate hydrogenation mechanism.