Mesoporous multi-shell spongy nanosphere NiCo metal/metal oxide hybrid for decarboxylation of fatty acid and upgrading of sludge bio-crude

A mesoporous, multi-shell, spongy nanosphere NiCo metal/metal oxide hybrid was synthesized using glucose reduction method, and the metal/metal oxide ratio can be regulated by adjusting the amount of glucose. The NiCo metal/metal oxide hybrid outperformed NiCo metal catalyst on decarboxylation reaction, and achieved a 100 % conversion of stearic acid and a 98 % yield of heptadecane under 1 MPa H₂ at 280 °C for 3 h. Despite of that metal active sites are well recognized responsible for decarboxylation, the better performance of hybrid was attributed to the co-existence of metal oxide and carbon that played an important role in separating metal particles and preventing them from aggregation, and thus exposed more active metal sites. Moreover, electron transfer from metal oxide to metal has been detected, which facilitated the adsorption of the carboxyl carbocation on metal sites and the concomitant efficient decarboxylation. The catalyst also performed efficiently on the catalytic upgrading of sludge bio-crude.