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

Abstract

Global greenhouse effect is being exacerbated by continuously increasing CO 2 emissions. Hence, we prepared a nanoscale zero-valent Ni-Fe alloy featuring a dual galvanic effect to facilitate the formation of formate by CO 2 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 Ni 0 and Fe 0 . According to the catalyst characterizations before and after the reaction, experimental phenomena, and related literatures, we proposed that the dual galvanic effect between Ni 0 and Fe 0 was an especially important mechanism to promote the release of BH 4-n (OH) n -(n = 0-3) from KBH 4 , which acted as the hydrogen donor for CO 2 . Furthermore, the optimization of process parameters was carried out to determine the optimal experimental conditions: the catalyst dosage was 1 g•L -1 , the KBH 4 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 CO 2 conversion efficiency and the formate selectivity reached 60.50 and 54.97%, respectively. Our research results can provide reference for the development of novel CO 2 resource utilization technologies.