The Electrocatalytic Performance of Rare Earth Ion Doped Co_0.2Ni_0.8-MOF-74 Catalyst for Nitrogen Reduction

We took Co_0.2Ni_0.8-MOF-74 with bimetallic synergistic effect as the basic material, and selected rare earth ions Ho, Gd, and Er with ion radii close to Co and Ni as the research objects for doping. The influence of rare earth ion doping amount and doping type on the eNRR performance of the catalyst was explored. The experimental results show that the ammonia yield rate and Faraday efficiency doped with Co_0.2Ni_0.8-MOF-0.5Ho are the highest, reaching 1.28 × 10⁻¹⁰ mol·s⁻¹·cm⁻²/39.8%, which is higher than the 1.12 × 10⁻¹⁰ mol·s⁻¹·cm⁻²/32.2% of Co_0.2Ni_0.8-MOF-74, and is about 14.3%/23.7% higher than that without doping, respectively. And the stability of Co_0.2Ni_0.8-MOF-0.5Ho is good(after 80 hours of continuous testing, the current density did not significantly decrease). This is mainly due to doping, which gives Co_0.2Ni_0.8-MOF-74 a larger specific surface area and catalytic active sites. The catalyst doped at the same time has more metal cation centers, which increases the electron density of the metal centers and enhances the corresponding eNRR performance.