Enhanced catalytic activity of MXene for nitrogen electoreduction reaction by carbon doping

The electrocatalytic performance of nitrogen reduction reaction (NRR) is seriously hindered by the lack of cost-effective electrocatalysts with high-efficiency and high-selectivity. In this work, the NRR catalytic activity of single carbon (C) atom embedded into two-dimensional (2D) transition metal carbides (M2CO2, M = Ti, Zr, Hf, Nb, Ta, Mo, and W) with oxygen vacancy was systematically evaluated by means of comprehensive density functional theory (DFT) computations. Our results revealed that the embedded single C atom possesses good durability due to its strong interaction with metal atoms around vacancy in these MXenes. Interestingly, through high-throughput screening, the single C atoms anchored on Nb2CO2, Mo2CO2, and W2CO2 nanosheets are identified as promise NRR catalysts with high-activity due to their low limiting potentials (-0.14 to -0.38 V) via a distal mechanism and outstanding selectivity again the competing hydrogen evolution reaction. Remarkably, the intrinsic activity of the C single atom supported by these MXenes mainly originates from the activation degree of the adsorbed N-2 molecule, which is greatly dependent on the electron filling degree of p(z) orbital in C atom. Thus, by carefully choosing suitable substrates, the single C catalyst can be utilized as ideal NRR catalysts for NH3 synthesis. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

The study evaluates the NRR catalytic activity of single carbon atom embedded in two-dimensional transition metal carbides, showing potential for high activity and selectivity. By choosing suitable substrates, the single C catalyst can be utilized as ideal NRR catalysts for NH3 synthesis.