Oxygen vacancy enables electrochemical N2 fixation over WO3 with tailored structure. (August 2019)

• Record Type: Journal Article
• Authors: Sun, Zhenyu; Huo, Rupeng; Choi, Changhyeok; Hong, Song; Wu, Tai-Sing; Qiu, Jieshan; Yan, Chao; Han, Zishan; Liu, Yongchao; Soo, Yun-Liang; Jung, Yousung
• Is Part Of: Nano energy. Volume 62(2019)
• Page Start: 869
• Page End: 875
• Publication Date: 2019-08
• Subjects: WO3 nanosheets -- Nitrogen reduction -- Defect engineering -- Electrocatalyst; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2019.06.019
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Electrochemical ammonia production under ambient conditions remains a grand challenge. Herein, we demonstrate that efficient binding and reduction of N2 at low overpotentials can be realized over WO3 with tailored surface oxygen vacancies, as predicted by density functional theory studies and evidenced by an NH3 yield rate of 4.2 μgNH3 h −1 mgcat. −1 and a faradaic efficiency of 6.8% at −0.12 V ( vs . the reversible hydrogen electrode). A high NH3 faradaic efficiency of up to 12.8% is obtained at an overpotential of only 80 mV, which can even be further improved by increasing the electrolyte pH to suppress the competing hydrogen evolution reaction. This low-cost metal oxide holds great appeal as one of the most promising electrocatalysts for efficient N2 fixation. Graphical abstract: The potential role of oxygen vacancies in WO3 on its N2 activation was elucidated by density functional calculations and verified experimentally, evidenced by remarkably enhanced electrocatalytic reduction of N2 to NH3 over thin WO3 nanosheets with tailored surface oxygen vacancies.Image 1 Highlights: We first demonstrate efficient binding and reduction of N2 at low overpotentials over WO3 with tailored surface oxygen vacancies. The surface oxygen vacancy concentration has a significant impact on N2 adsorption and activation of the N≡N triple bond, thereby enhancing electrocatalytic N2 fixation.