A Generalized Surface Chalcogenation Strategy for Boosting the Electrochemical N2 Fixation of Metal Nanocrystals. Issue 24 (10th May 2020) - Yang, Chengyong
Abstract: Electrocatalytic nitrogen reduction reaction (NRR) is a promising process relative to energy‐intensive Haber–Bosch process. While conventional electrocatalysts underperform with sluggish paths, achieving dissociation of N2 brings the key challenge for enhancing NRR. This study proposes an effective surface chalcogenation strategy to improve the NRR performance of pristine metal nanocrystals (NCs). Surprisingly, the NH3 yield and Faraday efficiency (FE) (175.6 ± 23.6 mg h –1 g –1 Rh and 13.3 ± 0.4%) of Rh‐Se NCs is significantly enhanced by 16 and 15 times, respectively. Detailed investigations show that the superior activity and high FE are attributed to the effect of surface chalcogenation, which not only can decrease the apparent activation energy, but also inhibit the occurrence of the hydrogen evolution reaction (HER) process. Theoretical calculations reveal that the strong interface strain effect within core@shell system induces a critical redox inversion, resulting in a rather low valence state of Rh and Se surface sites. Such strong correlation indicates an efficient electron‐transfer minimizing NRR barrier. Significantly, the surface chalcogenation strategy is general, which can extend to create other NRR metal electrocatalysts with enhanced performance. This strategy open a new avenue for future NH3 production for breakthrough in the bottleneck of NRR. Abstract : Surface chalcogenation is demonstrated as a highly universal and efficient strategy to improve the electrocatalytic nitrogen reduction reaction (NRR) performance of various metal nanocrystals (NCs), where the optimized surface selenated Rh NCs (Rh‐Se NCs) exhibit excellent NRR performance with NH3 production about 16.0 folds higher than that of Rh NCs, opening a versatile approach for future NH3 production.