Effects of hydrophobic layer on selective electrochemical nitrogen fixation of self-supporting nanoporous Mo4P3 catalyst under ambient conditions

Abstract

Electrochemical nitrogen reduction reaction (ENRR) of N2 to NH3 under ambient condition offers an environmentally-friendly and sustainable development approach that is expected to replace energy-intensive Haber-Bosch process. However, the ENRR process is suppressed with competition from unavoidable hydrogen evolution reaction (HER). Herein, we modify d-band structure of self-supporting nanoporous Mo4P3 (np-Mo4P3) catalyst by preparing fluorosilane (FAS) hydrophobic layer on the ligament surface. This approach weakens the absorbability of H and simultaneously prevent water close to active site, further suppress HER. Besides, the self-supporting nanoporous structure provides rich active sites for ENRR. The hydrophobic np-Mo4P3 exhibits good ENRR performance, such as high FE of 10.1 % and superior NH3 yield of 17.3 μg h−1 cm-2. The hydrophobization method offers an attractive strategy for suppressing HER and could be extended across metal catalyst for ENRR and CO2 reduction reaction.