A Generalized Surface Chalcogenation Strategy for Boosting the Electrochemical N2 Fixation of Metal Nanocrystals
Chengyong Yang1,2, Bolong Huang3, Shuxing Bai1, Yonggang Feng1, Qi Shao1, and Xiaoqing Huang1,2*（黄小青）
1College of Chemistry Chemical Engineering and Materials Science,Soochow University,Jiangsu 215123, China
2College of Chemistry and Chemical Engineering,Xiamen University,Xiamen 361005, China
3Department of Applied Biology and Chemical Technology,The Hong Kong Polytechnic University,Hung Hom, Kowloon, Hong Kong SAR, China
C.Y., B.H., and S.B. contributed equally to this work.
Adv. Mater. 2020, 2001267
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.