*2.2. Catalytic Testing*

Catalytic activity tests for dry reforming reaction were carried out in a 10 mm i.d. and 40 cm long stainless steel-tube at atmospheric pressure using 600 mg of a catalyst sample. Prior to the reaction, hydrogen gas (40 mL/min) was used to activate the catalyst and to reduce the nickel oxide at 550 ◦C for 90 min. Nitrogen was flown through the reactor to purge hydrogen and to cool down the reactor to the target reaction temperature. The feed gas had volume ratio of 17/17/2 corresponding to methane/carbon dioxide/nitrogen mixture with total feed flow rate of 36 mL/min. The products and unconverted reactants were monitored by an online gas chromatograph (SRI Instruments) equipped with a flame ionization detector (FID) and a thermal conductivity detector (TCD).
