Assembly of Hydrophobic ZIF-8 on CeO₂ Nanorods as High-Efficiency Catalyst for Electrocatalytic Nitrogen Reduction...

The electrocatalytic nitrogen reduction reaction (NRR) can use renewable electricity to convert water and N₂ into NH₃ under normal temperature and pressure conditions. However, due to the competitiveness of the hydrogen evolution reaction (HER), the ammonia production rate (R_NH3) and Faraday efficiency (FE) of NRR catalysts cannot meet the needs of large-scale industrialization. Herein, by assembling hydrophobic ZIF-8 on a cerium oxide (CeO₂) nanorod, we designed an excellent electrocatalyst CeO₂-ZIF-8 with intrinsic NRR activity. The hydrophobic ZIF-8 surface was conducive to the efficient three-phase contact point of N₂ (gas), CeO₂ (solid) and electrolyte (liquid). Therefore, N₂ is concentrated and H⁺ is deconcentrated on the CeO₂-ZIF-8 electrocatalyst surface, which improves NRR and suppresses HER and finally CeO₂-ZIF-8 exhibits excellent NRR performance with an R_NH3 of 2.12 μg h^-1 cm^-2 and FE of 8.41% at -0.50 V (vs. RHE). It is worth noting that CeO₂-ZIF-8 showed excellent stability in the six-cycle test, and the R_NH3 and FE variation were negligible. This study paves a route for inhibiting the competitive reaction to improve the NRR catalyst activity and may provide a new strategy for NRR catalyst design.