In situ localization of BiVO4 onto two-dimensional MXene promoting photoelectrochemical nitrogen reduction to ammonia

The existing industrial ammonia synthesis usually adopts the Haber-Bosch process, which requires harsh conditions of high temperature and high pressure, and consumes high energy. Under this circumstance, photoelectrochemical (PEC) catalysis is regarded as a promising method for N-2 reduction reaction (NRR), but bears problems of low efficiency and yield. Thus, exploring active catalysts remains highly desirable. In this work, BiVO4@MXene hybrids have been facilely synthesized by a hydrothermal route. The heterojunctions by the in situ growth of BiVO4 onto two-dimensional (2D) MXene greatly increase the NRR efficiency: under photoelectric conditions, the optimized NH3 yield is 27.25 mu g h(-1) cm(-2), and the Faraday efficiency achieves 17.54% at -0.8 V relative to the reversible hydrogen electrode (RHE), which are higher than most state-of-the-art NRR (photo) electrocatalysts. The mechanism speculation shows the enhanced light absorption range and the heterojunction formation largely promote the separation and the transfer efficiency of photogenerated carriers, thereby improving the PEC catalytic ability. Therefore, this work provides a hybrid route to combine the advantages of photo and electric catalysis for effective artificial nitrogen fixation. (C) 2022 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

In this work, BiVO4@MXene hybrids were synthesized by a hydrothermal route, and the heterojunctions formed greatly improved the efficiency of NRR. The optimized NH3 yield and Faraday efficiency under photoelectric conditions were higher than most state-of-the-art NRR electrocatalysts. The enhanced light absorption range and heterojunction formation were speculated to promote the separation and transfer efficiency of photogenerated carriers, thereby enhancing the PEC catalytic ability.