Schottky Barrier‐Induced Surface Electric Field Boosts Universal Reduction of NO<sub><i>x</i></sub><sup>−</sup> in Water to Ammonia
Peng Gao, Zhong‐Hua Xue, Shi‐Nan Zhang, Dong Xu, Guangyao Zhai, Qi‐Yuan Li, Jie‐Sheng Chen, Xin‐Hao Li
Abstract
Abstract NO x − reduction acts a pivotal part in sustaining globally balanced nitrogen cycle and restoring ecological environment, ammonia (NH 3 ) is an excellent energy carrier and the most valuable product among all the products of NO x − reduction reaction, the selectivity of which is far from satisfaction due to the intrinsic complexity of multiple‐electron NO x − ‐to‐NH 3 process. Here, we utilize the Schottky barrier‐induced surface electric field, by the construction of high density of electron‐deficient Ni nanoparticles inside nitrogen‐rich carbons, to facilitate the enrichment and fixation of all NO x − anions on the electrode surface, including NO 3 − and NO 2 − , and thus ensure the final selectivity to NH 3 . Both theoretical and experimental results demonstrate that NO x − anions were continuously captured by the electrode with largely enhanced surface electric field, providing excellent Faradaic efficiency of 99 % from both electrocatalytic NO 3 − and NO 2 − reduction. Remarkably, the NH 3 yield rate could reach the maximum of 25.1 mg h −1 cm −2 in electrocatalytic NO 2 − reduction reaction, outperforming the maximum in the literature by a factor of 6.3 in neutral solution. With the universality of our electrocatalyst, all sorts of available electrolytes containing NO x − pollutants, including seawater or wastewater, could be directly used for ammonia production in potential through sustainable electrochemical technology.