The surface of nanostructured (Ni)CoAl2O4 spinel and their study in dry reforming of methane

Ni x Co 1-x Al 2 O 4 (x = 0–0.5) catalysts were prepared by the co-precipitation from solution of Ni, Co and Al nitrates. The dry gel was heated at 700 °C in air and resulting alumina modified by nickel and cobalt ions is formed with spinel structure. The in situ X-ray diffraction study of these precursors in the reduction by a H 2 -containing gas mixture at 700 °C and ex situ after preliminary reduction in a H 2 -containing gas mixture and further work under reaction medium conditions showed that ensembles of Ni-Co alloy particles 3-4 nm in size are formed on the spinel surface. The influence of the composition of the catalysts and the duration of their testing on the catalytic properties in the dry reforming of methane reaction (DRM) was studied. The Ni 0.35 Co 0.65 Al 2 O 4 catalyst is stable in the DRM for 20 hours with CH 4 conversion of 76 % and an H 2 yield of 42 % (T = 700 °C, t = 30 ms). The high catalytic activity of the obtained catalysts in DRM is due to the formation of highly dispersed (3–4 nm) nanoparticles of the Ni-Co alloy an active phase in an amount of 17–18 wt. % on the initially large specific surface area of a spinel, stabilized by nickel and cobalt ions, and possessing mobile bulk oxygen under reducing reaction conditions.