TY - JOUR
T1 - Prediction of Highly Selective Electrocatalytic Nitrogen Reduction at Low Overpotential on a Mo-Doped g-GaN Monolayer
AU - Li, Lesheng
AU - Martirez, J. Mark P.
AU - Carter, Emily A.
N1 - Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/11/6
Y1 - 2020/11/6
N2 - Identifying efficient electrocatalysts with low overpotential and high selectivity for producing ammonia from nitrogen gas is essential for any future electrocatalytic nitrogen reduction reaction (NRR)-based ammonia synthesis. Via density functional theory calculations and the computational hydrogen electrode model, we systematically examine the prospect of using a single-transition-metal (TM)-atom-doped graphene-like GaN (g-GaN) monolayer as an electrocatalyst for artificial nitrogen reduction. Among 15 TMs investigated, the Mo-doped g-GaN (Mo@g-GaN) monolayer is the only electrocatalyst predicted to be feasible for the NRR. The Mo@g-GaN monolayer satisfies all screening criteria considered for activating the inert NN triple bond effectively, including stabilization of the adsorbed (*) NRR intermediate *NNH and destabilization of the *NH2 species. This monolayer also possesses sufficient overall stability. A complete analysis of the likely mechanisms involved in the NRR on this catalyst suggests that the Mo@g-GaN monolayer could exhibit promising NRR catalytic activity. It achieves this via one specific (distal) pathway, which has a very low onset potential of -0.33 V vs the reversible hydrogen electrode (RHE), corresponding to a low overpotential of 0.42 V vs the RHE, defined using the measured equilibrium potential for NRR of 0.09 V vs the RHE. The potential-determining step, conversion of *NH2 to *NH3, also exhibits a surmountable barrier of 0.42 eV, suggesting kinetics will be facile. Finally, the Mo@g-GaN monolayer is predicted to exhibit substantial selectivity (∼31%) toward ammonia synthesis over the competing hydrogen evolution reaction. These findings may open a potential route for artificial ammonia synthesis using a single-atom catalyst under ambient conditions.
AB - Identifying efficient electrocatalysts with low overpotential and high selectivity for producing ammonia from nitrogen gas is essential for any future electrocatalytic nitrogen reduction reaction (NRR)-based ammonia synthesis. Via density functional theory calculations and the computational hydrogen electrode model, we systematically examine the prospect of using a single-transition-metal (TM)-atom-doped graphene-like GaN (g-GaN) monolayer as an electrocatalyst for artificial nitrogen reduction. Among 15 TMs investigated, the Mo-doped g-GaN (Mo@g-GaN) monolayer is the only electrocatalyst predicted to be feasible for the NRR. The Mo@g-GaN monolayer satisfies all screening criteria considered for activating the inert NN triple bond effectively, including stabilization of the adsorbed (*) NRR intermediate *NNH and destabilization of the *NH2 species. This monolayer also possesses sufficient overall stability. A complete analysis of the likely mechanisms involved in the NRR on this catalyst suggests that the Mo@g-GaN monolayer could exhibit promising NRR catalytic activity. It achieves this via one specific (distal) pathway, which has a very low onset potential of -0.33 V vs the reversible hydrogen electrode (RHE), corresponding to a low overpotential of 0.42 V vs the RHE, defined using the measured equilibrium potential for NRR of 0.09 V vs the RHE. The potential-determining step, conversion of *NH2 to *NH3, also exhibits a surmountable barrier of 0.42 eV, suggesting kinetics will be facile. Finally, the Mo@g-GaN monolayer is predicted to exhibit substantial selectivity (∼31%) toward ammonia synthesis over the competing hydrogen evolution reaction. These findings may open a potential route for artificial ammonia synthesis using a single-atom catalyst under ambient conditions.
KW - density functional theory calculations
KW - gallium nitride monolayer
KW - nitrogen reduction reaction
KW - selectivity
KW - single-atom catalysts
UR - http://www.scopus.com/inward/record.url?scp=85096077182&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85096077182&partnerID=8YFLogxK
U2 - 10.1021/acscatal.0c03140
DO - 10.1021/acscatal.0c03140
M3 - Article
AN - SCOPUS:85096077182
SN - 2155-5435
VL - 10
SP - 12841
EP - 12857
JO - ACS Catalysis
JF - ACS Catalysis
IS - 21
ER -