Working-in-tandem mechanism of multi-dopants in enhancing electrocatalytic nitrogen reduction reaction performance of carbon-based materials

Developing carbon-based electrocatalysts with excellent N2 adsorption and activation capability holds the key to achieve highly efficient nitrogen reduction reaction (NRR) for reaching its practical application. Here, we report a highly active electrocatalyst—metal-free pyrrolic-N dominated N, S co-doped carbon (pyrr-NSC) for NRR. Based on theoretical and experimental results, it is confirmed that the N and S-dopants practice a working-in-tandem mechanism on pyrr-NSC, where the N-dopants are utilized to create electropositive C sites for enhancing N2 adsorption and the S-dopants are employed to induce electron backdonation for facilitating N2 activation. The synergistic effect of the pyrrolic-N and S-dopants can also suppress the irritating hydrogen evolution reaction, further boosting the NRR performance. This work gives an indication that the combination of two different dopants on electrocatalyst can enhance NRR performance by working in the two tandem steps—the adsorption and activation of N2 molecules, providing a new strategy for NRR electrocatalyst design.