Liu Xu, Cheng Xuetao, Zhao Huilin, Liu Pengfei, Wang Yan-Qin
Inner Mongolia Key Laboratory of Chemistry and Physics of Rare Earth Materials, College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot 010021, China.
Inorg Chem. 2024 Jul 29;63(30):14093-14102. doi: 10.1021/acs.inorgchem.4c01924. Epub 2024 Jul 12.
Electrochemical nitrate reduction (NORR) to ammonia production is regarded as one of the potential alternatives for replacing the Haber-Bosch technology for realizing artificial ammonia synthesis. In this study, a CuCoO/CuO-Ar heterostructure in the shape of dandelion nanospheres formed by nanoarrays has been successfully constructed, demonstrating excellent NORR performance. Experimental results indicate that Ar plasma etching of CuCoO/CuO-Ar significantly increases the content of oxygen vacancies compared to the sample of CuCoO/CuO-Air etched by air plasma, resulting in improved NORR performance. Density functional theory calculations further confirm that the existence of more oxygen vacancies effectively decreases the energy barrier of nitrate adsorption, which is due to the generation of more oxygen vacancies facilitating nitrate adsorption and weakening the N-O bonds of nitrate after plasma treatment. As a result, CuCoO/CuO-Ar exhibits a high NH yield of 0.55 mmol h cm and a Faraday efficiency of 95.07% at the optimal potential of -0.9 V (vs RHE) in a neutral medium. Importantly, CuCoO/CuO-Ar also showcases excellent electrocatalytic stability. This study presents new views on the design and structure regulation of NORR electrocatalysts and their potential applications in the future.
电化学硝酸盐还原（NORR）制氨被认为是替代哈伯-博施法实现人工合成氨的潜在方法之一。在本研究中，成功构建了由纳米阵列形成的蒲公英纳米球形状的CuCoO/CuO-Ar异质结构，展现出优异的NORR性能。实验结果表明，与空气等离子体蚀刻的CuCoO/CuO-Air样品相比，Ar等离子体蚀刻的CuCoO/CuO-Ar显著增加了氧空位的含量，从而提高了NORR性能。密度泛函理论计算进一步证实，更多氧空位的存在有效降低了硝酸盐吸附的能垒，这是因为等离子体处理后产生了更多促进硝酸盐吸附的氧空位并削弱了硝酸盐的N-O键。结果，在中性介质中，CuCoO/CuO-Ar在-0.9 V（相对于可逆氢电极）的最佳电位下表现出0.55 mmol h cm的高NH产率和95.07%的法拉第效率。重要的是，CuCoO/CuO-Ar还展现出优异的电催化稳定性。本研究为NORR电催化剂的设计和结构调控及其未来的潜在应用提供了新的观点。
