Pd nanocrystals grown on MXene and reduced graphene oxide co-constructed three-dimensional nanoarchitectures for efficient formic acid oxidation reaction.

Although direct formic acid fuel cell (DFAFC) is regarded as one of the most promising energy-conversion systems, its commercialization process is impeded by the high costs of electrode catalysts as well as the sluggish catalytic reaction kinetics. Herein, we present a convenient bottom-up method to the synthesis of nanosized Pd crystals grown on 3D porous hybrid nanoarchitectures constructed from MXene (Ti 3 C 2 T x) and reduced graphene oxide nanosheets (Pd/MX-rGO) through a co-assembly process. The as-derived 3D Pd/MX-rGO nanoarchitecture is equipped with a number of attractive textural features, such as 3D cross-linked porous networks, large specific surface area, uniform Pd dispersion, optimized electronic structure, and good electron conductivity. As a result, unusual formic acid oxidation properties in terms of high catalytic activity, strong poison tolerance, and reliable long-term stability are achieved for the 3D Pd/MX-rGO catalyst, significantly superior to those for conventional Pd catalysts supported by carbon black, graphene, and Ti 3 C 2 T x matrixes. The controllable growth of Pd nanocrystals on MXene and reduced graphene oxide co-constructed 3D nanoarchitectures is achieved by a bottom-up co-assembly method. By virtue of the porous networks and optimized electronic structure, the resulting 3D catalyst exhibits superior electrocatalytic properties toward formic acid oxidation reaction. Image 1 • The bottom-up construction of 3D Pd-decorated MXene/rGO architecture is achieved. • The 3D porous frameworks facilitate the transportation of both electrons and ions. • The incorporation of MXene can effectively optimize the electronic structure of Pd. • The resulting 3D architecture exhibits high activity for formic acid oxidation. [ABSTRACT FROM AUTHOR]