Anti-Coking Ni/SiO2 Catalyst for Dry Reforming of Methane: Role of Oleylamine/Oleic Acid Organic Pair

We demonstrate the synthesis of silica-supported Ni catalyst in the presence of oleylamine (OAm) and oleic acid (OAc) as the ligand and surfactant. Compared with OAm or OAc alone, Ni/SiO2 prepared with OAm/OAc organic pair showed a much smaller Ni particle, a much stronger metal-support interaction (MSI), an enhanced initial conversion of both CO2 and CH4 and a prolonged stability over 16h with zero carbon deposition. How the OAm/OAc organic pair affects the catalyst formation mechanism is proposed: OAc intimately interacts with silica by hydrogen bond formed between the carboxylic group and silanol group; OAm forms a complex with Ni and promotes the adsorption of Ni on silica through the basic property of amine ligand; amide formation between the carboxylic group of OAc and the amine group of OAm makes use of both additives; in addition, a stronger steric hindrance is given by the more complex aliphatic chain network of the pair, retarding the growth of Ni particles.