Sol–gel derived Ni–Mo bimetallic carbide catalysts and their performance for CO hydrogenation

A series of Ni–Mo bimetallic carbide catalysts were prepared by a sol–gel method using citric acid as complexing agent followed by temperature-programmed carburization in Ar, and characterized using XRD, XPS, N2-sorption, SEM and TEM. The N2-sorption and XRD experiments show that the Ni–Mo bimetallic carbide catalysts have moderately high surface area and contain β-Mo2C, Ni metal and Ni6Mo6C after being heated under flowing Ar. In CO hydrogenation, the Ni–Mo bimetallic carbide catalysts were much more active than the molybdenum carbide catalyst and the catalytic activity and product distribution strongly depended on the amount of Ni promoter. The alcohol yield increased with increasing Ni content, reaching maximum with Ni/Mo molar ratio of 0.5, and then decreased with further increasing Ni content. The Ni0.5MoC catalyst has the strongest Ni–Mo synergetic interaction from XPS experiment and the Ni6Mo6C might be the active site for alcohol synthesis.