Zha Yuankang, Liu Min, Wang Jinlu, Feng Jiyu, Li Daopeng, Zhao Dongnan, Zhang Shengbo, Shi Tongfei
Key Laboratory of Materials Physics, Institute of Solid State Physics, HFIPS, Chinese Academy of Sciences Hefei 230031 China
University of Science and Technology of China Hefei 230026 China.
RSC Adv. 2023 Mar 28;13(15):9839-9844. doi: 10.1039/d3ra00679d. eCollection 2023 Mar 27.
Electrochemical nitrate reduction reaction (NO RR) to synthesize valuable ammonia (NH) is considered as a green and appealing alternative to enable an artificial nitrogen cycle. However, as there are other NO RR pathways present, selectively guiding the reaction pathway towards NH is currently challenged by the lack of efficient catalyst. Here, we demonstrate a novel electrocatalyst for NO RR consisting of Au doped Cu nanowires on a copper foam (CF) electrode (Au-Cu NWs/CF), which delivers a remarkable NH yield rate of 5336.0 ± 159.2 μg h cm and an exceptional faradaic efficiency (FE) of 84.1 ± 1.0% at -1.05 V ( RHE). The N isotopic labelling experiments confirm that the yielded NH is indeed from the Au-Cu NWs/CF catalyzed NO RR process. The XPS analysis and infrared spectroscopy (IR) spectroscopy characterization results indicated that the electron transfer between the Cu and Au interface and oxygen vacancy synergistically decreased the reduction reaction barrier and inhibited the generation of hydrogen in the competitive reaction, resulting in a high conversion, selectivity and FE for NO RR. This work not only develops a powerful strategy for the rational design of robust and efficient catalysts by defect engineering, but also provides new insights for selective nitrate electroreduction to NH.
通过电化学硝酸盐还原反应（NO RR）合成有价值的氨（NH₃）被认为是实现人工氮循环的一种绿色且有吸引力的替代方法。然而，由于存在其他NO RR途径，目前缺乏高效催化剂，选择性地引导反应途径生成NH₃面临挑战。在此，我们展示了一种用于NO RR的新型电催化剂，它由泡沫铜（CF）电极上的金掺杂铜纳米线（Au-Cu NWs/CF）组成，在-1.05 V（相对于可逆氢电极，RHE）时，其NH₃产率高达5336.0±159.2 μg h⁻¹ cm⁻²，法拉第效率（FE）高达84.1±1.0%。氮同位素标记实验证实，生成的NH₃确实来自Au-Cu NWs/CF催化的NO RR过程。X射线光电子能谱（XPS）分析和红外光谱（IR）表征结果表明，铜和金界面之间的电子转移以及氧空位协同降低了还原反应势垒，并抑制了竞争反应中氢气的生成，从而实现了NO RR的高转化率、选择性和FE。这项工作不仅通过缺陷工程为合理设计稳健高效催化剂开发了一种有力策略，还为选择性硝酸盐电还原生成NH₃提供了新的见解。
