Biomass-Templated Synthesis of Ni–Co Bimetallic Catalysts for Efficient Stearic Acid Deoxygenation

The conversion of stearic acid to linear hydrocarbons represents a critical step in the advancement of sustainable biofuels and biochemicals. In this work, a confined NiCo bimetallic catalyst (Nix-Co/C@TSC) was assembled on biochar derived from natural Tung shell (TS) using an in situ growth approach for the H2-free catalytic deoxygenation of fatty acids. The catalyst exhibited exceptional catalytic performance, achieving a high conversion of 98.2% and a remarkable selectivity of 82.8% for heptadecane. Multiple characterization revealed that the Tung shell-derived biochar (TSC) support significantly enhanced the spatial dispersion of Co and Ni species, promoting the formation of the NiCo alloy phase. This structural modification, combined with improved reactant adsorption capabilities, synergistically boosted the overall catalytic activity. In situ DRIFTS analysis revealed that CoOx species activate stearic acid via strong carboxyl-group adsorption, while Ni preferentially promotes the decarboxylation pathway by stabilizing key intermediates, collectively facilitating heptadecane formation. This work develops a novel dual carbon-supported bimetallic catalyst system, offering a promising strategy for the efficient conversion of stearic acid into high-value hydrocarbon products.