Ni[sbnd]Y2O3[sbnd]Al2O3 aerogel catalysts with high coke deposition resistance for syngas production by biogas reforming

Abstract

The control of coke deposition is one of the most important challenges during reforming processes using Ni/Al2O3 catalysts. To minimize the effects of coke deactivation and increase the catalytic performance, NiY2O3Al2O3 aerogel catalysts were synthesized by the epoxide-initiated gelation method and dried with supercritical CO2. The catalysts with yttria added were evaluated in terms of syngas production and coke formation in biogas reforming reactions in the temperature range of 500–800 °C. The techniques used to characterize the catalysts were nitrogen adsorption tests, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma optical emission spectroscopy, thermogravimetric analysis, scanning and transmission electron microscopy. Nanoscale and mesoporous catalysts with high specific surface area were obtained. The catalysts maintained an amorphous structure with high metal dispersion and homogeneous distribution. Yttria insertion promoted higher interaction between the active phase and the support in the catalysts. For the first time, profiles for the coke deposition and syngas production were determined simultaneously during reforming reactions. Hydrogen production increased with yttria addition on the catalysts. The syngas production was highest at 800 °C. However, the hydrogen production was highest at 600 and 700 °C. The coke-resistance of the catalysts decreased in the following order: NiY2.5Al > NiY5Al > NiAl > NiY10Al. The yttria promoter showed a decrease in the coke formation of 58 wt% compared to NiAl at 700 °C. NiY2O3Al2O3 aerogel catalysts are a promising alternative in the search for high-coke-resistance catalysts and for increasing the syngas production in biogas reforming reactions.