Constructing the V<sub>o</sub>-TiO<sub>2</sub>/Ag/TiO<sub>2</sub> Heterojunction for Efficient Photoelectrochemical Nitrogen Reduction to Ammonia
Sheng Lin, Jun-Bo Ma, Jiangjian Fu, Lan Sun, Hua Zhang, Jun Cheng, Jian‐Feng Li
Abstract
Photoelectrochemical (PEC) nitrogen (N 2 ) fixation technology provides the possibility to produce ammonia (NH 3 ) under mild conditions, but the efficiency of N 2 reduction in this process is greatly limited due to the high bond energy and ionic potential of N 2 . Herein, the V o -TiO 2 /Ag/TiO 2 photoelectrode consisting of rutile TiO 2 nanorod arrays, Ag nanoparticles, and anatase TiO 2 nanosheets with oxygen vacancies (V o -TiO 2 ) was constructed for accelerating the PEC reduction of N 2 into ammonia. The separation of photogenerated carriers can be promoted by the heterojunction among TiO 2 nanorods, Ag nanoparticles, and V o -TiO 2 nanosheets. Furthermore, the photogenerated electrons from the conduction band of TiO 2 and the hot electrons from Ag nanoparticles’ local surface plasmon resonance (LSPR) effect were injected into the conduction band of V o -TiO 2, and they were further captured by V o -TiO 2 oxygen vacancy and can reduce N 2 that adsorbed on the catalyst to NH 3 . Without any sacrificial agent, the average NH 3 production rate can reach 51.2 μg h –1 cm –2 . The catalyst exhibited excellent stability even after multiple uses. The LSPR effect of Ag nanoparticles and heterojunction structure promote the better PEC performance of TiO 2 nanorod arrays.