Enhancing CO₂ electroreduction via nitrogen-doping in Zn-MOFs: Structural optimization, stability, and high faraday efficiency for CH₄/CO production

Different concentrations of N-doped modified Zn-based metal-organic frameworks (xN-Zn-MOFs) were prepared by a solvothermal method, as well as the successful synthesis of 0N-Zn-MOFs as well as 1N-Zn-MOFs and 2N-Zn-MOFs catalytic materials. The experimental results suggested that 2N-Zn-MOF displayed the maximum specific surface area and pore size among the three materials. The catalytic material stability and CO 2 reduction reaction (CO 2 RR) activity were investigated by linear sweep voltammetry (LSV), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronocurrent tests (I-T). The corresponding Faraday efficiency (FE) was calculated in conjunction with product analysis. Among the three catalytic materials, 2N-Zn-MOF had the optimal catalytic reduction performance with a maximum current density of 20 mA-cm −2 ; Its charge transfer resistance was 7.84 Ω. It was stably tested at a potential of −0.45 V (vs. RHE) for 12 h in the IT test, and its reduction products were methane (CH 4 ) and carbon monoxide (CO), with a maximum total Faraday efficiency of 30.64 %.