Hydrogen spillover in alkaline solutions for effective nitrogen fixation

Abstract

Electrocatalytic nitrogen reduction reaction (NRR) to produce ammonia (NH3) is a promising alternative strategy for Haber-Bosch process. However, the sluggish reaction dynamics and inferior NH3 selectivity, which majorly depend on the hydrogen transfer rate from the electrolyte to N2, hinder practical application of Electrocatalytic NRR. Herein, we purposefully design a hydrogen spillover strategy by the Density-Functional Theory calculation to accelerate the hydrogen transfer rate. By conducting NRR in an alkaline solution, the competing HER is suppressed. The designed active center (Fe/SV-Mo2N) can simultaneously adsorb OH− and N2 and activate them, promoting the hydrogen spillover from *OH to *N2 and improving the NRR property with the limiting potential of −0.22 V vs. RHE. The proof-of-concept experiment confirms that the catalyst has good NRR performance with the highest NH3 yield rate of 36.4 μg h−1 mg−1 and a high FE of 17.6 % at −0.15 V vs. RHE in an alkaline solution. This catalytic strategy provides a new perspective to rationally design catalysts for promoting NRR performance.