Ni₅Ga₃-based catalysts hold promise for CO₂ reduction into methanol because the operating pressure is significantly lower than that required for commercial catalysts. While the synergy between Ni₅Ga₃ and Ga₂O₃ is crucial in methanol synthesis, the controllable formation of Ga₂O₃ on Ni₅Ga₃ nanoparticles and their structure-related interactions under varied preparation conditions remain underexplored. This study introduces a series of Ni₅Ga₃ catalysts derived from the reduction of oxide precursors prepared via a combustion method with different fuels like oxalic acid, citric acid, and urea. Besides the combustion processes that were studied, various characterization techniques disclosed that the components and physicochemical properties of these catalysts can be strongly influenced by the choice of fuel, affecting the Ni₅Ga₃ nanoparticle size along with the content of Ga₂O₃ and, consequently, the catalytic performance toward CO₂ reduction. The catalysts prepared with oxalic acid were composed of the smallest Ni₅Ga₃ nanoparticles and the most abundant Ga₂O₃ species and thus exhibited the best performance compared to its counterpart. In addition, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis was performed to provide insights into reaction intermediates and mechanisms. This study highlights the critical role of Ga₂O₃ in catalytic efficiency and underscores the influence of the synthesis parameters on the performance of Ni₅Ga₃ catalysts in CO₂ hydrogenation to methanol.

中文翻译：

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通过无溶剂路线制备的 Ni5Ga3 催化剂在常温压力下 CO2 加氢制甲醇：结构和成分的影响


Ni₅Ga₃ 基催化剂有望将 CO₂ 还原成甲醇，因为其操作压力明显低于商业催化剂所需的压力。虽然 Ni₅Ga₃ 和 Ga₂O₃ 之间的协同作用在甲醇合成中至关重要，但 Ga₂O₃ 在 Ni₅Ga₃ 纳米颗粒上的可控形成及其在不同制备条件下的结构相关相互作用仍未得到充分探索。本研究介绍了一系列 Ni₅Ga₃ 催化剂，这些催化剂是通过燃烧法用草酸、柠檬酸和尿素等不同燃料制备的氧化物前驱体的还原衍生的。除了研究的燃烧过程外，各种表征技术还表明，这些催化剂的成分和物理化学性质会受到燃料选择的强烈影响，从而影响 Ni₅Ga₃ 纳米颗粒的尺寸以及 Ga₂O₃ 的含量，从而影响还原 CO₂ 的催化性能。用草酸制备的催化剂由最小的 Ni₅Ga₃ 纳米颗粒和最丰富的 Ga₂O₃ 物种组成，因此与同类催化剂相比表现出最佳性能。此外，还进行了漫反射红外傅里叶变换光谱 （DRIFTS） 分析，以深入了解反应中间体和机理。 本研究强调了 Ga₂O₃ 在催化效率中的关键作用，并强调了合成参数对 Ni₅Ga₃ 催化剂在 CO₂ 加氢制甲醇中性能的影响。