CO₂ hydrogenation using H₂ was investigated using mesoporous bimetallic aluminum spinel oxides (MAl₂O₄, where M was Mg, Co, Cu, or Zn) as heterogeneous base catalysts. They could catalyze CO₂ hydrogenation without additional catalytic metal components. Most catalysts produced CO as the major product (>80%) and relatively small amounts of CH₄ and CH₃OH. However, when CoAl₂O₄ was used as catalyst, CH₄ was the major product (>80%). A systematic relationship was discovered between the amount of strong basic sites and CO₂ conversion. As the amount of strong basic sites increased, the CO₂ conversion increased with a linear relationship over all the tested reaction temperatures (300–400 °C). However, no systematic relationship was observed between the CO₂ conversion and total amount of basic sites, which suggested that only the sufficiently strong basic sites could activate CO₂ efficiently. In addition, owing to the high surface area of the mesopores, the catalytic activity of the spinel oxides increased because of the facile diffusion of molecules through their mesoporous channels. Assuming that the strong basic sites were the actual catalytic sites, the apparent activation energies of all catalysts were derived. The results indicated that CuAl₂O₄ having the highest amount of strong basic sites presented the lowest activation energy of 13.0 kJ mol⁻¹. This reemphasized the idea that the strong basic sites were useful for the effective activation of CO₂ with small energy input. Accordingly, these spinel oxides could be further used for designing multifunctional catalysts supporting catalytic metal nanoparticles on their mesopore walls, which is under investigation.

使用介孔双金属铝尖晶石氧化物（MAl ₂ O ₄，其中M为Mg，Co，Cu或Zn）作为多相碱催化剂，研究了使用H ₂进行CO ₂加氢。它们可以催化CO ₂加氢而无需其他催化金属组分。大多数催化剂产生的主要产物为CO（> 80％）和相对少量的CH ₄和CH ₃ OH。然而，当使用CoAl ₂ O ₄作为催化剂时，CH ₄是主要产物（> 80％）。发现强碱位的量与CO ₂之间存在系统关系转换。随着强碱性位点数量的增加，在所有测试的反应温度（300–400°C）下，CO ₂转化率呈线性关系增加。然而，在CO ₂转化率与碱性位点总量之间没有观察到系统的关系，这表明只有足够强的碱性位点才能有效地激活CO ₂。另外，由于介孔的表面积大，由于分子易于通过其介孔通道扩散，尖晶石氧化物的催化活性增加。假定强碱性位点是实际的催化位点，则得出所有催化剂的表观活化能。结果表明，CuAl ₂ O₄具有强碱性位的最高量呈现13.0千焦摩尔的最低活化能^-1。这再次强调了这样的想法，即强碱性位点对于以小能量输入有效激活CO ₂是有用的。因此，这些尖晶石氧化物可进一步用于设计在其中孔壁上担载催化金属纳米颗粒的多功能催化剂，这正在研究中。