▎ 摘　　要

A new oxygen-annealing treatment for Pd supported on graphene was employed to enhance the electro-catalytic performance in formic acid microfluidic fuel cells. Experiments show that both the electro-oxidation reactivity and CO tolerance of the annealed catalyst are significantly improved. When testing the fuel cell, the maximum power density with annealed catalyst is 41% higher than the unannealed Pd@graphene catalyst, and 85% higher than Pd@Vulcan XC-72. This enhancement is attributed to the Pd-O bond formation during the oxygen annealing step, which induces greater CO electro-oxidation reactivity. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.