Nanoscale zero‐valent Ni–Fe alloy catalyst featuring a dual galvanic effect to promote formate formation by CO2 hydrogenation

Global greenhouse effect is being exacerbated by continuously increasing CO2 emissions. Hence, we prepared a nanoscale zero‐valent Ni–Fe alloy featuring a dual galvanic effect to facilitate the formation of formate by CO2 hydrogenation in this work. The properties of the bimetallic nanocatalyst were characterized by various techniques, such as X‐ray photoelectron spectrometer, X‐ray powder diffraction, and high‐resolution transmission electron microscopy, indicating that the major phase composition was an alloy of Ni0 and Fe0. According to the catalyst characterizations before and after the reaction, experimental phenomena, and related literatures, we proposed that the dual galvanic effect between Ni0 and Fe0 was an especially important mechanism to promote the release of BH4‐n(OH)n– (n = 0–3) from KBH4, which acted as the hydrogen donor for CO2. Furthermore, the optimization of process parameters was carried out to determine the optimal experimental conditions: the catalyst dosage was 1 g·L–1, the KBH4 concentration was 0.2 mol·L–1, the reaction temperature was 65 °C, the solution pH was 9.5 and the flue gas velocity was 0.5 L·min–1. The average CO2 conversion efficiency and the formate selectivity reached 60.50 and 54.97%, respectively. Our research results can provide reference for the development of novel CO2 resource utilization technologies. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd.