Designing advanced catalysts for electrosynthesis of urea is of significance yet remains challenging. Herein, ultrathin two-dimensional Mo-doped PdIn bimetallene nanoribbons were synthesized via a one-pot method. Material characterization and electrochemical study revealed that the alloying effect enabled electron transfer from In to Pd and provided dual metal sites with regulated electronic structure for the adsorption and activation of NO3- and CO2, thus facilitating the generation of key active intermediates and promoting the C-N coupling reaction.