Engineering coke-resistant with metal promoted Ni/silica–zirconia catalysts for syngas production via dry reforming of methane

• Ga, La, Gd, Sr, Sm promoted Ni-catalyst dispersed over SZ31107 (5Ni/SZ) is tested. • Coke deposition is least over Ga-promoted catalyst which acquires strong metal support interaction. • 5Ni1La/SZ has intermediate level MSI seeking 42% H 2 yield ( Y H 2 ) and 65% wl. • 5Ni1Sm/SZ shows least crystallinity additionally ensuing 53% Y H 2 & 30% wl. • Reaction condition’s optimization sets maximum Y H 2 & least wl. % over Sm-catalyst. • At ∼ 844 °C, ∼23 Lg⁻ 1 h⁻ 1 , 0.667 CH 4 CO 2 ; Sm-catalyst gives 87% Y H 2 & 1.78% wl in 30 h. Dry reforming of methane (DRM) reaction utilizes greenhouse gas, CH 4 and CO 2 for yielding syngas, a crucial synthetic feedstock. Herein, Ni-catalyst supported over silica-zirconia (Ni/SZ) and the role of promoters like Ga, Gd, La, Sm, and Sr are investigated towards the DRM reaction. Catalysts are characterized by X-ray diffraction, X-ray photoelectron/Raman spectroscopy, adsorption isotherm, and thermogravimetry Analysis (TGA), Temperature-programmed reduction/desorption (TPR/TPD), and transmission electron microscopy (TEM). The catalytic activity of the Ga-promoted catalyst is limited due to its high crystallinity and lowest surface area. Gd-promoted catalyst is additionally facilitated by strong basic sites, resulting in less coke deposition and improved catalytic activity than the La-promoted catalyst. Sr-promoted catalyst is enriched with basic sites and acquires an equal concentration of NiO under weak, moderate and strong interaction. The CH 4 conversion capacity of the Sr-promoted catalyst is impressive and second highest after the Sm-promoted catalyst. The Sm-promoted catalysts acquire the least crystallinity and the highest concentration of NiO-under moderate interaction. Moderate interaction of NiO over the support facilitates good reducibility while maintaining the stability of active sites. In long time on stream over Sm-promoted catalyst, the coke nature is changed to amorphous, which is easily gasified, making the catalyst coke resistant and leaving the catalyst surface exposed for consistent high performance. The 5Ni1Sm/SZ catalyst attains the highest catalytic activity; it achieves 87% H 2 yield over 30 h time on stream at 844 °C, a WHSV of 22892 cc g⁻ 1 h⁻ 1 , and a CH 4 /CO 2 ratio of 0.667. The thorough study of promoted catalyst systems, selection of the best promoted catalyst, and optimization of reaction conditions by respond surface methodology over the best catalyst evolves the 5Ni1Sm/SZ catalyst as a high-performance catalyst for a long time on stream.