| Autor: |
Rehman, Faisal, Kwon, Soonho, Hossain, Md Delowar, Musgrave III, Charles B., Goddard III, William A., Luo, Zhengtang |
| Zdroj: |
Journal of Materials Chemistry A; 11/21/2022, Vol. 10 Issue 43, p23323-23331, 9p |
| Abstrakt: |
Environmental and energy considerations demand that the Haber-Bosch process for reducing N2 to NH3 be replaced with electrochemical ammonia synthesis where the H atoms come from water instead of from H2. But a practical realization of electrochemical N2 reduction reaction (NRR) requires the development of new generation electrocatalysts with low overpotential and high Faraday efficiency (FE). A major problem here is that the hydrogen evolution reaction (HER) competes with NRR. Herein, we consider new generation dual-site catalysts involving two different metals incorporated into a novel two-dimensional C3N–C2N heterostructure that provides a high concentration of well-defined but isolated active sites that bind two distinct metal atoms in a framework that facilitates electron transfer. We report here the mechanism and predicted kinetics as a function of applied potential for both NRR and HER for the (Fe–Ru)/C3N–C2N dual atom catalyst. These calculations employ the grand canonical potential kinetics (GCP-K) methodology to predict reaction free energies and reaction barriers as a function of applied potential. The rates are then used in a microkinetic model to predict the turn-over-frequencies (TOF) as a function of applied potential. At U = 0 V, the FE for NRR is 93%, but the current is only 2.0 mA cm−2. The onset potential (at 10 mA cm−2) for ammonia on Fe–Ru/C3N–C2N is −0.22 VRHE. This leads to a calculated TOF of 434 h−1 per Fe–Ru site. We expect that the mechanisms for NRR and HER developed here will help lead to new generations of NRR with high TOF and FE. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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