Formamide Electrosynthesis from Methanol and Ammonia in Water over Pr-Doped MnO₂

A rare earth element doping strategy is reported to boost the activity and enhance the stability of MnO₂ for selective formamide production through electrocatalytic oxidation coupling (EOC) of methanol and ammonia. MnO₂ doped with 1% Pr was selected as the best candidate with an optimized formamide yield of 211.32 μmol cm^-2 h^-1, a Faradaic efficiency of 22.63%, and a stability of more than 50 h. The easier formation of Mn⁶⁺ species and the lower dissolution rate of Mn species over Pr-doped MnO₂ revealed by in situ Raman spectra were responsible for the boosted formamide production and enhanced stability. In addition, a two-electrode flow electrolyzer was developed to integrate EOC with C₂H₂ semihydrogenation for simultaneously producing value-added products in both the anode and cathode.