The CO2 hydrogenation reaction is a cornerstone reaction in catalytic conversion technologies, with Ru/TiO2 catalysts being amongst the most active and selective for CH4 formation. A key factor in the preparation of such catalysts is the choice of chemical precursor for Ru impregnation, as it can substantially influence the physicochemical properties and catalytic performance. In this study, we deliberately employ a simple incipient wetness impregnation method to isolate the effect of the Ru precursor itself, using two different Ru precursors for the synthesis of Ru/TiO2 catalysts intended for CO2 hydrogenation and evaluating their properties using analytical techniques such as XRF, XRD, TEM, XPS and H2-TPR. Our results show that catalysts prepared from ruthenium nitrosyl nitrate solutions display enhanced reducibility and slightly stronger metal–support interactions compared to those prepared from ruthenium chloride solutions. These features enable higher CO2 conversion and CH4 selectivity. The results of this work provide grounds for the targeted chemical precursor selection, while clarifying the reason behind the observed effects on catalytic performance.
Bikogiannakis et al. (Sun,) studied this question.