Molybdenum Nitrides, Carbides and Phosphides as Highly Efficient Catalysts for the (hydro)Deoxygenation Reaction
Abstract
Transition metal nitrides, carbides and phosphides have the potential to replace the expensive and hazardous catalysts typically used for the conversion of fatty acids. However, there has been little research on the influence of treatment conditions and precursor nature on the properties of such catalytic systems.
To better understand these dependencies, we synthesized a number of Mo catalysts by temperature-programmed reduction (700-900 degrees C; CH4/N-2, N-2/H-2) using ammonium heptamolybdate, diammonium phosphate and hexamethylenetetramine (HMT) as Mo, C, N and P sources. The presence of HMT in the precursor mixtures ensured the synthesis of pure phase Mo2C, Mo2N and MoP.
Catalytic activity in the (hydro)deoxygenation of stearic acid (240 min; 360 degrees C; 50 bar of H-2) decreased in the following order: Mo2C>Mo2N>MoP. However, all of the studied Mo-based catalysts showed good deoxygenation efficiency and, thus, represent excellent alternatives to traditional noble and sulfur-containing catalysts.