Dual Electron Donating Metal-Boron Reaction Center Boosts Electrocatalytic Urea Synthesis from N2 and CO2

Urea (NH2CONH2) production by electrosynthesis at mild conditions has been hampered due to the lack of systematic evaluation of pathways in effectively activating inert N-2 and CO2 molecules and facilitating the formation of C-N bonds. In this work, we evaluated 16 transition metal (M) atoms anchored on carbon nitride nanosheet with boron (B) doping (M-B@C2N) for boosting urea production by theoretical calculations. All possible urea synthesis pathways, (i) CO2 pathway, (ii) OCOH pathway, (iii) CO pathway, and (iv) NCON pathway, were comparatively studied on Cu, Fe, Co, Ni-B@C2N. This systematic calculation identified that the first reduction of *N-2 is the key step for urea synthesis. We found that the bond index of *N-2 shows a strong correlation with Delta G*N-2 ->*NNH, so they are promising descriptors for screening. Through the screening, we found that Nb- and Mo-B@C2N show a low limiting potential of -0.56 and -0.53 V. Although previous studies found that spin could promote C-C bond formation on M-B@C2N, we found that for C-N coupling, such effects by spin were only active for Nb-B@C2N. Combining boron and early transition metal atoms allows for neighboring reaction sites that simultaneously donate electrons to activate inert N2 and CO2 for efficient urea synthesis.