Wang Dongdong, Fan Guilan, Luan Deyan, Guo Yan, Gu Xiaojun, Lou Xiong Wen David
Department of Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong, 999077, China.
Hong Kong Branch of National Precious Metals Material Engineering Research Center, City University of Hong Kong, Hong Kong, 999077, China.
Adv Mater. 2024 Dec;36(50):e2408580. doi: 10.1002/adma.202408580. Epub 2024 Nov 6.
Electrocatalytic reduction of nitric oxide (NO) to ammonia (NH) represents a potential solution for improving the disrupted nitrogen cycle balance. Unfortunately, designing efficient electrocatalysts for NO reduction reaction (NORR) remains a notable challenge, especially at low concentrations. Herein, a displacement-alloying strategy is reported to successfully induce the phase transition of Co nanoparticles supported on carbon nanosheets from face-centered cubic (fcc) to hexagonal close-packed (hcp) structure through Ru incorporation. The obtained RuCo alloy with hcp phase structure (hcp-RuCo) exhibits apparent NORR activity with a record-high Faraday efficiency of 99.2% and an NH yield of 77.76 µg h mg at -0.1 V versus reversible hydrogen electrode at a NO concentration of 1 vol %, surpassing Co nanoparticles with fcc phase structure and most reported catalysts. Density functional theory calculations reveal that the excellent NORR activity of hcp-RuCo can be attributed to the optimized electronic structure of Co site and lowered energy barrier of the potential rate-determining step through phase transition. Furthermore, the assembled Zn-NO battery using hcp-RuCo as the cathode achieves a power density of 2.33 mW cm and an NH yield of 45.94 µg h mg . This work provides a promising research perspective for low-concentration NO conversion.
将一氧化氮（NO）电催化还原为氨（NH₃）是改善被破坏的氮循环平衡的一种潜在解决方案。不幸的是，设计用于NO还原反应（NORR）的高效电催化剂仍然是一个显著的挑战，尤其是在低浓度情况下。在此，据报道一种置换合金策略通过掺入Ru成功诱导了负载在碳纳米片上的Co纳米颗粒从面心立方（fcc）相转变为六方密排（hcp）结构。所获得的具有hcp相结构的RuCo合金（hcp-RuCo）表现出明显的NORR活性，在相对于可逆氢电极-0.1 V、NO浓度为1 vol%的条件下，法拉第效率高达99.2%，NH₃产率为77.76 μg h mg⁻¹，超过了具有fcc相结构的Co纳米颗粒以及大多数已报道的催化剂。密度泛函理论计算表明，hcp-RuCo优异的NORR活性可归因于Co位点的电子结构优化以及通过相变降低了潜在速率决定步骤的能垒。此外，使用hcp-RuCo作为阴极组装的Zn-NO电池实现了2.33 mW cm⁻²的功率密度和45.94 μg h mg⁻¹的NH₃产率。这项工作为低浓度NO转化提供了一个有前景的研究视角。
