Enhanced catalytic deoxygenation of stearic acid into biofuels over supported FeNi catalysts

Although FeNi bimetal-based materials have been used for the deoxygenation of different substrates, no applicable and green support has been reported to load FeNi alloy for the deoxygenation of stearic acid. Furthermore, the activation energy of stearic acid deoxygenation on a FeNi-based catalyst is uncharted and the reaction mechanism remains ambiguous. Herein, we integrate FeNi bimetals on activated carbon (AC) as an efficient green catalyst for the deoxygenation of stearic acid into biofuels. The catalytic performance was systematically investigated with respect to Fe/Ni molar ratios and calcination temperatures. FeNi bimetals supported on AC (FeNi/AC-500) exhibited higher catalytic activity than their monometallic counterparts, indicating the importance of synergistic effect and interaction between Fe and Ni for the deoxygenation of stearic acid. Especially, Fe1Ni3/AC-900 calcined at 900 degrees C demonstrated the highest stearic acid conversion and linear C17 hydrocarbon (viz., heptadecane and 1-heptadecene) selectivity of 99 % and 94 %, respectively, due to the optimal formation of ordered Fe1Ni3 alloy phases and the lowest apparent activation energy of stearic acid pyrolysis. The distinguished performance surpassed that of noble metal and toxic catalysts in literature works. Therefore, a low-cost, green yet effective FeNi-based catalyst with low activation energy has been developed for the deoxygenation of stearic acid into biofuels.