Copper nanowires decorated with TiO2−x from MXene for enhanced electrocatalytic nitrogen oxidation into nitrate under vacuum assistance
Quan Li, Zhengting Xiao, Weina Jia, Qin Li, Xianguo Li, Wentai Wang, Xianguo Li, Wentai Wang
Abstract
The green synthesis of nitrate (NO 3 − ) via electrocatalytic nitrogen oxidation reaction (NOR) is a promising strategy for artificial nitrogen fixation, which shows great advantages than traditional nitrate synthesis based on Haber–Bosch and Ostwald processes. But the poor N 2 absorption, high bond energy of N≡N (941 kJ·mol −1 ), and competing multi-electron-transfer oxygen evolution reaction (OER) limit the activity and selectivity. Herein, we fabricated MXene-derived irregular TiO 2− x nanoparticles anchored Cu nanowires (Cu-NWs) electrode for efficient electrocatalytic nitrogen oxidation, which exhibits a NO 3 − yield of 62.50μ g ·h −1 ·mg cat −1 and a Faradaic efficiency (FE) of 22.04%, and a significantly enhanced NO 3 − yield of 92.63 μ g ·h −1 ·mg cat −1 , and a FE of 40.58% under vacuum assistance. The TiO 2− x /Cu-NWs electrode also shows excellent reproducibility and stability under optimal experimental conditions. Moreover, a Zn-N 2 reaction device was assembled with TiO 2− x /Cu-NWs as an anode and Zn plate as a cathode, obtaining an extremely high NO 3 − yield of 156.25 μ g ·h −1 ·mg cat −1 . The Zn-nitrate battery shows an open circuit voltage (OCV) of 1.35 V. This work provides novel strategies for enhancing the performance of ambient N 2 oxidation to obtain higher NO 3 − yield.