Ambient electrocatalytic nitrogen reduction on a MoO2/graphene hybrid: experimental and DFT studies

Abstract

Rational design of effective electrocatalysts toward the N₂ reduction reaction (NRR) is essential for achieving high-efficiency electrocatalytic NH₃ synthesis. Herein, a hybrid catalyst of MoO₂ nanoparticles on reduced graphene oxide (MoO₂/RGO) was developed to catalyze the NRR under ambient conditions. Electrochemical measurements demonstrated that MoO₂/RGO presented a high NRR activity with an NH₃ yield of 37.4 μg h⁻¹ mg⁻¹ and a faradaic efficiency of 6.6% at −0.35 V (vs. RHE) in 0.1 M Na₂SO₄, comparable to or exceeding those of most reported NRR electrocatalysts. Density functional theory calculations disclosed that the MoO₂/RGO hybrid possessed stronger electronic interactions with *N₂H and donated more electrons from active Mo sites to *N₂H relative to MoO₂ alone, largely reducing the energy barrier for *N₂H formation, which was the potential-determining step of the NRR process. These results highlight the promising potential of the hybridization strategy and MoO₂/RGO hybrid for applications in ambient electrocatalytic NH₃ synthesis.