Environment-Dependent Structural Evolution and Electrocatalytic Performance in N2 Reduction of Mo-Based ZIF-8

In this study, we used in situ transmission electron microscopy to probe the structural evolution of Mo-based zeolite imidazole framework-8 (Mo-ZIF-8) under various gaseous environments. Upon pyrolyzing Mo-ZIF-8 under oxidative, inactive, and reductive environments, the formation of Mo-related materials, including Mo2C, Mo nanoparticles, Mo nanoclusters, and Mo single atoms (Mo-SAs), is well-controlled to be anchored on the porous N-doped carbon (PNC), and the evolution mechanisms are clearly provided. Furthermore, we discussed the performance of the Mo-related materials/PNC for the electrochemical nitrogen reduction reaction (NRR). Mo-SA/PNC achieves a maximum NH3 yield rate of 15.34 μg h–1 mg–1 and a Faradic efficiency of 24.03% for NRR at a potential of −0.2 V versus reversible hydrogen electrode. Our findings suggest guidelines for the rational design of the derivatives of metal-based metal–organic frameworks and their feasible application.