Catalytic performance of carbon-supported mixed MoW carbides for the deoxygenation of stearic acid

Abstract

Supported bimetallic molybdenum and tungsten carbides are viable replacements for noble metal catalysts and are suitable for the decarboxylation/decarbonylation and (hydro-)deoxygenation of renewable triglyceride‑based feedstocks. Here, we show that the Mo:W ratio in bimetallic carbide can steer the product yield towards either aldehydes, alcohols, alkenes or alkanes. The mixed carbides with a higher Mo/W ratio (3:1) reached higher yields of aldehydes and alcohols, while the carbides with a lower Mo/W (1:3) ratio yielded high concentrations of alkenes. Interestingly, a physical mixture of two monometallic (1 +1) carbides had a similar catalytic performance to the 1:1 mixed carbides. The intrinsic activity (turnover frequency (TOF)) of the catalysts was assessed based on both H2 and CO chemisorption. The TOFH2 related linearly with the Mo/W ratio, while the TOFCO did not show a relevant relationship. Therefore H2 chemisorption is suggested as the preferred way to assess the intrinsic activities of these catalysts.