Composition-dependent electrochemical activity of Ag-based alloy nanotubes for efficient nitrogen reduction under ambient conditions

Abstract

The composition-activity relationship is highly desirable for electrocatalytic nitrogen reduction reaction (NRR) because it could guide the rational design of efficient NRR catalysts. In this work, the composition effect of Ag-based alloy nanotubes on electrocatalytic NRR activity is systematically investigated. It is found that, among AgAu nanotubes with atomic ratio from 8:1 to 1:2, Ag2Au1 alloy nanotubes achieve the largest enhancement for NRR catalytic activity. Specifically, the NH3 production rate and faradaic efficiency of Ag2Au1 nanotubes are 21.7 μg h−1 mgcat−1 and 3.8% at −0.30 V vs. RHE, respectively, which were 3.0 and 3.6 times higher than those of Ag nanowires. Compared with Ag2Pd1 and Ag2Pt1 nanotubes, Ag2Au1 hollow nanotubes also exhibit a better NRR catalytic activity. Theoretical calculation results indicate that the negative ion characteristic of Au atoms in the Ag2Au1 alloy is favorable for the adsorption and activation of N2. Moreover, Ag2Au1 nanotubes showed stable NH3 yield rate and faradaic efficiency up to 18 h, revealing its great potential for promising NRR electrocatalysis.