*2.1. Catalyst Synthesis*

In order to synthesize 5 wt% nickel-based catalysts, nitrate salt precursor [(Ni(NO3)2·6H2O)] was wet impregnated over different supports including Y-zeolite (Y), H-ZSM-5 (H) and alumina (A) to synthesize catalysts denoted as NY, NH, and NA, where N represents 5 wt% Ni and Y, and H and A represent respective supports. Briefly, 30 mL of 28 mM of nickel precursor solution were added dropwise to a suspension of the individual oxide supports (33 g/L) in deionized water stirred with magnetic bar at 300 rpm. This process was carried out at 60 ◦C. The catalysts were subsequently dried overnight (12 h) at 110 ◦C under atmospheric before being subjected to calcination at 500 ◦C in MTI®® furnace for 3 h under air atmosphere. The catalyst preparation steps and DRM over catalyst surface are pictorially depicted in Scheme 1.

**Scheme 1.** Catalyst preparation steps and depiction of reforming reaction over catalyst.
