Syngas production from reforming of greenhouse gases CH4/CO2 over Ni-Cu/Al2O3 nanocatalyst: Impregnated vs. plasma-treated catalyst

Ni-Cu/Al2O3 nanocatalyst was synthesized via impregnation method and treated using non-thermal plasma method. Reforming of CH4/CO2 over synthesized nanocatalyst was studied in a quartz tubular micro-reactor at CH4/CO2 feed ratios of 1 and 1.5, temperature range of 650-850 degrees C, atmospheric pressure, GHSV of 24, 36, 48, and 60 l/g h. The plasma-treated nanocatalyst was more active compared to the impregnated nanocatalyst. The plasma-treated Ni-Cu/Al2O3 nanocatalyst obtained same feed conversion and product yield at lower temperatures compared to impregnated sample. Various methods including XRD, FESEM, TEM, EDX, BET, TG-DTG, XPS, and FTIR techniques were applied to study physicochemical properties of synthesized nanocatalyst. XRD results showed larger NiO crystals in plasma-treated Ni-Cu/Al2O3 nanocatalyst while the morphology of this sample was more uniform and agglomeration free. TEM analysis indicated regular shape but big size for active phase particles in plasma treated sample similar to the XRD results. The plasma-treated Ni-Cu/Al2O3 nanocatalyst lost about 10% and 12% of CH4 and CO2 conversions, respectively, during 1440 min time on stream test. While the reactivity of nanocatalyst was morphology sensitive and dependent to degree of particle agglomeration and synergetic effect between Ni and Cu particles, the stability of the nanocatalyst was directly dependent on size of NiO crystals. (C) 2014 Elsevier Ltd. All rights reserved.