Promoting methane combustion activity and stability by tuning multiple Ni–Si interactions in catalysts

Catalytic combustion holds great promise for eliminating unburned methane released by the natural gas industry, and the crucial factor is the development of cost-effective and efficient catalysts. Herein, the silicon component was introduced into nickel oxide by simultaneously regulating the precipitation of nickel precursors and the hydrolysis of silicon precursors. The generation of SiO4 groups in NiO inhibited the growth and sintering of NiO grains, meanwhile promoting the formation of active Ni2+ and adsorbed oxygen species for activation and oxidation of methane. With the increase of Si content, the existence of surface nickel silicate on NiO further improved the sinter resistance of NiO, but caused the diminish of Ni2+ and surface adsorbed oxygen species. The catalytic activity and stability were co-enhanced via facilely tuning the multiple Ni–Si interactions. The catalyst with abundant SiO4 groups and negligible nickel silicate exhibited considerably higher catalytic activity, sinter-resistance and water-resistance than NiO toward methane combustion.