Role of promoters over yttria‐zirconia supported Ni catalyst for dry reforming of methane

Abstract

Dry reforming of methane (DRM) bears great hope for the catalytic community as well as environmentalists for its potential to convert two greenhouse gases, CH4 and CO2, together into synthetic feedstock “syngas”. The stable tetragonal zirconium yttrium oxide phase over the “Yttria‐zirconia supported Ni” catalyst (Ni/YZr) brings >70% CH4 conversion against 50% CH4 conversion over zirconia supported Ni catalyst) in 7 h time‐on‐stream (TOS). The use of the second metal oxide (MOx; M = Ho, Ga, Gd, Ba, Cs) in a small amount (4 wt%) over Ni/YZ catalyst is found to promote the catalytic activity further. Herein, we have prepared such metal‐promoted yttria‐zirconia supported Ni catalyst, employed them for DRM and characterized them with surface area porosity, X‐ray diffraction, spectroscopic techniques, temperature programmed techniques and transmission electron microscopy. A fine correlation of characterization results with catalytic activity brings out various useful information that would be useful for establishing yttria‐zirconia supported Ni catalyst for DRM. Ni stabilized over cubic zirconium holmium oxide phase in 5Ni4Ho/YZr catalyst, cubic zirconium gadolinium oxide phase in 5Ni4Gd/YZr catalyst and cubic zirconium barium oxide phase in 5Ni4Ba/YZr catalyst perform excellent toward DRM. Catalytically, 5Ni4Ho/YZr catalyst achieves CH4 conversion as high as ~85% whereas 5Ni4Ba/YZr and 5Ni4Gd/YZr show CH4 conversions of about ~80%. Even in 30 h TOS study, 5Ni4Ho/YZr catalyst showed >81% CH4 conversion with retaining highest H2/CO (0.97).