Catalytic conversion of greenhouse gases (CO2 and CH4) to syngas over Ni-based catalyst: Effects of Ce-La promoters by Farooqi, Ahmad Salam, Al-Swai, Basem M., Ruslan, Farida Hamimi, Mohd. Zabidi, Noor Asmawati, Saidur, R., Syed Muhammad, Syed Anuar Faua'ad, Abdullah, Bawadi