Defective TiO<sub>2−</sub><i><sub>x</sub></i> for High‐Performance Electrocatalytic NO Reduction toward Ambient NH<sub>3</sub> Production
Zixiao Li, Qiang Zhou, Jie Liang, Longcheng Zhang, Xiaoya Fan, Donglin Zhao, Zhengwei Cai, Jun Li, Dongdong Zheng, Xun He, Yongsong Luo, Yan Wang, Binwu Ying, Hong Yan, Shengjun Sun, Jing Zhang, Abdulmohsen Ali Alshehri, Feng Gong, Yinyuan Zheng, Xuping Sun
Abstract
Abstract Synthesis of green ammonia (NH 3 ) via electrolysis of nitric oxide (NO) is extraordinarily sustainable, but multielectron/proton‐involved hydrogenation steps as well as low concentrations of NO can lead to poor activities and selectivities of electrocatalysts. Herein, it is reported that oxygen‐defective TiO 2 nanoarray supported on Ti plate (TiO 2− x /TP) behaves as an efficient catalyst for NO reduction to NH 3 . In 0.2 m phosphate‐buffered electrolyte, such TiO 2− x /TP shows competitive electrocatalytic NH 3 synthesis activity with a maximum NH 3 yield of 1233.2 µg h −1 cm −2 and Faradaic efficiency of 92.5%. Density functional theory calculations further thermodynamically faster NO deoxygenation and protonation processes on TiO 2− x (101) compared to perfect TiO 2 (101). And the low energy barrier of 0.7 eV on TiO 2− x (101) for the potential‐determining step further highlights the greatly improved intrinsic activity. In addition, a Zn‐NO battery is fabricated with TiO 2− x /TP and Zn plate to obtain an NH 3 yield of 241.7 µg h −1 cm −2 while providing a peak power density of 0.84 mW cm −2 .