Bimetallic NiFe catalysts have emerged as a promising alternative to the traditional Ni catalysts for CO₂ methanation. However, the promoting effect of Fe on the bimetallic catalysts remains ambiguous. In this study, a series of NiFe catalysts derived from hydrotalcite precursors were investigated. In situ x-ray diffraction (XRD) analysis revealed that small NiFe alloy particles were formed and remained stable during reaction. When Fe/Ni = 0.25, the alloy catalysts exhibited the highest CO₂ conversion, CH₄ selectivity and stability in CO₂ methanation at low temperature of 250–350 °C. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) study indicated that the formate pathway was the most plausible reaction scheme on both Ni and NiFe alloy catalysts, while a moderate addition of Fe facilitated the activation of CO₂ via hydrogenation to *HCOO. Density functional theory (DFT) calculations further demonstrated that the overall energy barrier for CH₄ formation was lower on the alloy surface.

双金属NiFe催化剂已成为有前途的CO ₂甲烷化甲烷Ni催化剂的替代品。但是，Fe对双金属催化剂的促进作用仍然不清楚。在这项研究中，研究了一系列由水滑石前体衍生的NiFe催化剂。原位X射线衍射（XRD）分析表明，形成了小的NiFe合金颗粒，并在反应过程中保持稳定。当Fe / Ni = 0.25时，合金催化剂在250–350°C的低温下表现出最高的CO ₂转化率，CH ₄选择性和CO ₂甲烷化的稳定性。在原位漫反射红外傅里叶变换光谱法（DRIFTS）的研究表明，甲酸途径是在Ni和NiFe合金催化剂上最合理的反应方案，而适度添加的Fe则通过加氢生成* HCOO促进了CO ₂的活化。密度泛函理论（DFT）计算进一步证明，在合金表面形成CH ₄的总能垒较低。