Can Two Metals Be Chosen Independently for Electrochemical C–N Coupling?

Electrochemical C–N coupling could produce urea directly from CO or CO2 and nitrogen oxides under mild conditions. Bimetallic catalysts offer neighboring sites with different binding preferences, but choosing a suitable metal for each intermediate does not necessarily identify the most active pair. We screen 80 ordered A3B surfaces and investigate how metal selection affects reactivity at Zn3M interfaces using DFT transition-state calculations and comparative kinetic modeling. Although *CO and *N preferentially bind to different metals, both retain their metal coordination in the C–N bond-forming transition state. Changing the CO-binding metal therefore affects both CO availability and the coupling barrier. Stronger CO binding can increase coverage while making bond formation more difficult. Zn3Cu has the lowest coupling barrier, but its low CO coverage limits the rate. Zn3Pt has a higher barrier yet gives the highest predicted comparative coupling rate among the alloys studied at U = 0 V versus RHE. This comparison shows how evaluating adsorption or bond-forming kinetics alone can misidentify the preferred metal pair. Considering their combined effects provides a mechanistic basis for prioritizing Zn-based bimetallic catalysts for experimental testing.