Valorization of biomass-derived carboxylic acids into drop-in fuels with the input of renewably sourced electricity is promising for a clean and sustainable energy future. Herein, self-supporting core-shell Pt@Ir nanothorns on 3D porous carbon fiber paper anodes have been employed for the electrocatalytic upgrading of carboxylic acids into fuel-range hydrocarbons. The core-shell anode is synthesized by electrodepositing Pt nanothorns on carbon fiber paper followed by galvanic deposition of a thin layer of Ir nanothorns on the surface. Pt@Ir exhibited a remarkably higher yield (49.5%) and Faraday efficiency (62.3%) for hydrocarbon production as compared to that of benchmark commercial Pt/C. The anode also has good recyclability with little activity loss after five successive runs. © 2019 American Chemical Society.