Multicomponent Co-based sol–gel catalysts for dry/steam reforming of methane

Abstract

The multicomponent Со–Pt–Zr/Al₂O₃ and Со–Pt–Zr–La/Al₂O₃ catalysts were prepared by the sol–gel method. The modified Pechini method was used as a sol–gel approach to synthesize a system containing Co, Pt, Zr, and La. The sol–gel materials prepared by such a manner were incorporated into alumina in order to form the catalyst granules. The physicochemical properties of the catalysts were studied by a number of methods (TEM, SEM, BET, XRD, H₂-TPR). It was found that the synthesized multicomponent catalysts are highly dispersed systems composed of metal oxides and various microalloys such as the bimetallic Co–Pt and perovskite type structures—LaCoO₃ and LaAlO₃ having mainly the particle size < 10 nm. The catalytic behaviour of the the new sol–gel materials was tested in dry reforming (DRM), steam reforming (SRM) and combined CO₂-Steam reforming of methane (bireforming, BRM) using a feed with a ratio of CO₂/CH₄/H₂O = 0 ÷ 1/1/0 ÷ 1.5 over the temperature interval of 300–800 °C, P = 0.1 MPa, and GHSV varied within 1000–4000 h⁻¹. The synthesized sol–gel catalysts performed the high activity, selectivity, and stability in all processes: DRM, BRM, and SRM with producing syngas with varied ratio of H₂/CO depending on a feed composition. Thus, H₂/CO ratio is varied within 0.9–4.4 while steam amount added to CH₄-CO₂ feed is grown from 0 to 1.5 volume parts. Almost complete methane conversion occurs at T = 750–800 °C. The long-term continuous testing of the Co–Pt–Zr–La/Al₂O₃ catalyst confirmed its stable work in methane conversion by carbon dioxide and/or steam for in total >200 h.

Highlights

• Со–Pt–Zr(La)/Al₂O₃ catalysts were synthesized by the modified Pechini sol–gel method.

• The sol-made catalyst is a highly dispersed system composed of metal oxides and microalloys – Co–Pt, LaCoO₃ and LaAlO₃.

• The sol–gel made catalysts perform the high activity and selectivity in syngas production by CH₄ conversion by CO₂ and/or steam.

• At relatively low temperature, 700–800 °C, the extent of CH₄ conversion is 90–99% depending on a feed composition.

• The catalyst is very stable and does not lose the activity for in total >200 h.