It's commonly known that the electrocatalytic nitrogen (N2) reduction reaction (NRR) can convert N2 and H2O into ammonia (NH3), one of the most essential chemicals in ecological system. With renewable electricity under mild conditions, it's envisaged as a promising strategy to replace the industrial Haber-Bosch process. However, this method is still far away from the practical application because the developed NRR electrocatalysts and electrocatalysis system possess low NH3 yield and current efficiency.