Post-synthetic Ti exchanged UiO-66-NH2 metal-organic frameworks with high faradaic efficiency for electrochemical nitrogen reduction reaction

Electrochemical nitrogen reduction reaction (NRR) is a promising approach for NH3 production to take place of the traditional Haber-Bosch process, which is still limited by the low NH3 yield rate and low Faradaic efficiency. Herein, Ti was post-synthetic exchanged into Zr-based metal organic frameworks to synthesize UiO-Zr-Ti as NRR electrocatalysts. The incorporated Ti is found to function as active sites for NRR and benefit the improved charge-transfer efficiency, which has a positive effect on the high NH3 yield rate. Moreover, the existence of Zr and Ti species can effectively suppress the competing HER, thus leading to high Faradaic efficiency. Therefore, the modified UiO-Zr-Ti-5d shows the highest NH3 yield rate of 1.16 × 10−10 mol cm−2 s−1 and the highest Faradaic efficiency of 80.36%, which is comparable to recently reported NRR electrocatalysts.