Oxide passivated Ni-supported Ru nanoparticles in silica: A new catalyst for low-temperature carbon dioxide methanation

•The non-alloyed Ni supported nano-Ru(Re, Rh, Ir or Pd) catalysts were synthesized.•Nano-Ru/Ni forms oxide passivated Ni-supported Ru nanoparticles.•Nano-Ru/Ni is highly efficient and selective catalyst of CO2 methanation at 200 °C.•Nano-Re/Ni is highly efficient and selective catalyst of the highest TOF at 460 °C.

We tested the catalytic performance of Ni-supported Ru nanoparticles in silica for the first time. The method for supporting Ru nanoparticles on Ni included the formation of nano-Ru/nano-SiO2, from which silica was digested in the presence of Ni. This provided a nano-Ru/Ni catalyst with an oxide passivation layer on the surface in which unalloyed metallic Ru and Ni were detected. This system, which was tested as a potential methanation catalyst, appears to be highly productive and efficient at low temperature, e.g. ca. 100% conversion can be achieved at ca. 200 °C at a high TOF value of 940 h−1. The longer reaction duration deactivated the catalyst by carbon deposition; however, it did not destroy the catalyst, which could be fully reactivated by hydrogen treatment. In turn, the highest methane productivity (among nano-Re, Rh, Ir or Pd/Ni) given by TOF value of ca. 13855 h−1 at higher temperature (460 °C) was observed for the nano-Re/Ni catalyst.

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