The effect of alkali promotion of TiO₂ on the CO₂ hydrogenation activity and selectivity has been investigated over 0.5%Ru/TiO₂ and 5%Ru/TiO₂ catalysts of different promoter type (Li, Na, K, Cs) and variable promoter loading (0.0–0.40 wt.%). The effect of alkali promotion was found to be more pronounced over catalysts of low Ru loading (or small Ru crystallites). In the case of 0.5%Ru/TiO₂ catalysts, both catalytic activity and methane selectivity are strongly enhanced with the addition of small amounts (0.2 wt.%) of alkalis following the order of TiO₂ (unpromoted) < Li ∼ K < Cs < Na. The intrinsic reaction rate exhibits a volcano-type dependence on the sodium content. Optimal results were obtained for 0.5%Ru/TiO₂ catalyst containing 0.2 wt.% Na, the specific activity of which is about 3 times higher, compared to that of the unpromoted sample. In the case of 5%Ru/TiO₂ catalysts, alkali addition does not practically affect catalytic activity and selectivity. Turnover frequency of 0.5%Ru/0.2%Na-TiO₂ catalyst is higher than that measured over 5%Ru/TiO₂, indicating that small amounts of alkalis can replace part of precious metals, reducing the cost and increasing the efficiency of the CO₂ methanation process.

在不同助催化剂类型（Li，Na，K，Cs）和可变助催化剂类型的0.5％Ru / TiO ₂和5％Ru / TiO ₂催化剂上，研究了碱促进TiO ₂对CO ₂氢化活性和选择性的影响。载量（0.0–0.40 wt。％）。发现碱促进作用比低Ru负载（或小的Ru微晶）的催化剂更明显。在0.5％Ru / TiO ₂催化剂的情况下，按照TiO ₂的顺序添加少量（0.2 wt。％）的碱会大大提高催化活性和甲烷选择性（未促进）<Li〜K <Cs <Na。本征反应速率表现出对钠含量的火山型依赖性。对于含有0.2重量％Na的0.5％Ru / TiO ₂催化剂，获得了最佳结果，其比活性是未促进样品的比活性的约3倍。在5％Ru / TiO ₂催化剂的情况下，碱的添加实际上不影响催化活性和选择性。0.5％Ru / 0.2％Na-TiO ₂催化剂的周转频率高于5％Ru / TiO _2时的周转频率，表明少量碱可以代替部分贵金属，从而降低了成本并提高了CO的效率₂甲烷化过程。