It is a paradox that the excess of carbon dioxide in our atmosphere can endanger lives and even the civilization that has been founded on carbon. Human addiction to carbon is persistent and therefore we need novel chemistry for the efficient conversion of CO₂ to harmless or useful products. Accordingly, catalytic CO₂ hydrogenation has been widely studied as a potential method for fuel engineering, and methane production in particular. Syngas, a blend of CO with H₂ has been observed as an incomplete product of this reaction. Here we report a surprising discovery that syngas to methane conversion can be attained in flow at temperatures starting from −7 °C with a hybrid bimetallic Ru/Ni catalyst. In turn, the ultra-low temperature effect cannot be observed for the Re/Ni and Pd/Ni combinations. To our knowledge, this is the first report showing that such a process can be performed at a temperature lower than the freezing point of water. These ultra-low temperature conditions could potentially lead to sustainable methane production.

In this study, we investigated the catalytic performance of Ru nanoparticles (NPs) supported on Ni-nanowires for the first time. This appears to be a highly efficient catalyst for low-temperature methanation, e.g., ca. 100% conversion and 100% of CH₄ selectivity can be achieved at ca. 179 °C, while the turnover frequency (TOF) value was 2479.2 h⁻¹. At the same time, the onset of a reaction was observed at a temperature as low as 130 °C. The comparison of nano-Pd and nano-Ru supported on Ni-nanowires enabled us to prove that oxidized surface metals are highly important for the high activity of the investigated nano-Ru@nanowired-Ni. Moreover, similar to the microscopic Sabatier rule, which indicates that some optimal reactivity level of a catalyst exists, we showed that Ni-nanowires (a higher specific surface area than a standard metal surface, e.g., in the form of a metal foam, but lower than nano-sized materials) significantly enhances the performance of the Ru-Ni catalytic system.