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 BH_4-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.

中文翻译：

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纳米级零价镍铁合金催化剂具有双重电偶效应，可促进 CO2 加氢形成甲酸盐

不断增加的 CO ₂排放正在加剧全球温室效应。因此，我们制备了一种具有双重电偶效应的纳米级零价镍铁合金，以促进在这项工作中通过 CO ₂加氢形成甲酸盐。通过X射线光电子能谱仪、X射线粉末衍射和高分辨率透射电子显微镜等多种技术对双金属纳米催化剂的性质进行了表征，表明其主要相组成为Ni ⁰和Fe ⁰的合金。根据反应前后催化剂的表征、实验现象和相关文献，我们提出 Ni ⁰和 Fe之间的双重电偶效应⁰是促进 BH _4-n (OH) _n ^– (n = 0-3) 从 KBH ₄释放的一个特别重要的机制，KBH ₄充当了 CO ₂的氢供体。进一步优化工艺参数，确定最佳实验条件：催化剂用量1 g·L ^–1，KBH ₄浓度0.2 mol·L ^–1，反应温度65℃，溶液pH 值为 9.5，烟气流速为 0.5 L·min ^–1。平均 CO ₂转化效率和甲酸盐选择性分别达到 60.50% 和 54.97%。我们的研究成果可为开发新型CO ₂资源利用技术提供参考。© 2021 化学工业协会和 John Wiley & Sons, Ltd.