ZnO Quantum Dots Coupled with Graphene toward Electrocatalytic N 2 Reduction: Experimental and DFT Investigations

Electrochemical reduction of N 2 to NH 3 is a promising method for artificial N 2 fixation, but it requires efficient and robust electrocatalysts to boost the N 2 reduction reaction (NRR). Herein, a combination of experimental measurements and theoretical calculations revealed that a hybrid material in which ZnO quantum dots (QDs) are supported on reduced graphene oxide (ZnO/RGO) is a highly active and stable catalyst for NRR under ambient conditions. Experimentally, ZnO/RGO was confirmed to favor N 2 adsorption due to the largely exposed active sites of ultrafine ZnO QDs. DFT calculations disclosed that the electronic coupling of ZnO with RGO resulted in a considerably reduced activation‐energy barrier for stabilization of *N 2 H, which is the rate‐limiting step of the NRR. Consequently, ZnO/RGO delivered an NH 3 yield of 17.7 μg h −1  mg −1 and a Faradaic efficiency of 6.4 % in 0.1  m Na 2 SO 4 at −0.65 V (vs. RHE), which compare favorably to those of most of the reported NRR catalysts and thus demonstrate the feasibility of ZnO/RGO for electrocatalytic N 2 fixation.