Synergizing Mo Single Atoms and Mo<sub>2</sub> C Nanoparticles on CNTs Synchronizes Selectivity and Activity of Electrocatalytic N<sub>2</sub> Reduction to Ammonia.
basic_science · Level V
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- Record sourced from PubMed, PMID 32627888.
- Also identified by DOI 10.1002/adma.202002177.
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Abstract
Previous research of molybdenum-based electrocatalysts for nitrogen reduction reaction (NRR) has been largely considered on either isolated Mo single atoms (MoSAs) or Mo carbide particles (e.g., Mo<sub>2</sub> C) separately, while an integrated synergy (MoSAs-Mo<sub>2</sub> C) of the two has never been considered. The theoretical calculations show that the Mo single atoms and Mo<sub>2</sub> C nanoparticles exhibit, respectively, different catalytic hydrogen evolution reaction and NRR selectivity. Therefore, a new role-playing synergistic mechanism can be well enabled for the multistep NRR, when the two are combined on the same N-doped carbon nanotubes (NCNTs). This hypothesis is confirmed experimentally, where the MoSAs-Mo<sub>2</sub> C assembled on NCNTs (MoSAs-Mo<sub>2</sub> C/NCNTs) yields an ammonia formation rate of 16.1 µg h<sup>-1</sup> cm<sub>cat</sub> <sup>-2</sup> at -0.25 V versus reversible hydrogen electrode, which is about four times that by the Mo<sub>2</sub> C alone (Mo<sub>2</sub> C/NCNTs) and 4.5 times that by the MoSAs alone (MoSAs/NCNTs). Moreover, the Faradic efficiency of the MoSAs-Mo<sub>2</sub> C/NCNTs is raised up to twofold and sevenfold of the Mo<sub>2</sub> C/NCNTs and MoSAs/NCNTs, respectively. The MoSAs-Mo<sub>2</sub> C/NCNTs also demonstrate outstanding stability by the almost unchanged catalytic performance over 10 h of the chronoamperometric test. The present study provides a promising new prototype of synchronizing the selectivity and activity for the multistep catalytic reactions.