The Fabrication of Mesoporous Palladium-Boron Alloy by a Dual-Force-Driven Self-Assembly Strategy for Enhancing the Electrocatalytic Formic Acid Oxidation Activity.

Pd-based catalysts are considered promising for the formic acid oxidation reaction (FAOR), whereas the toxic effect of poisoning intermediates greatly affects the stability and activity of the catalysts. Herein, a dual-force-driven self-assembly strategy is developed to synthesize mesoporous palladium-boron (meso-Pd-B) alloy using cationic polymer polyethyleneimine (PEI) as a pore-forming agent. In this strategy, PEI can interact with the Pd metal precursor via electrostatic and coordination interactions and self-assemble into stable organic-inorganic composites. Dimethylamine borane as a reducing agent together with boric acid enables the alloying of Pd with B, and the Pd-B alloy with mesoporous structure is obtained driven by dual forces. The strategy can be generalized to synthesize other mesoporous metal-B alloys (e.g., Pt-B, Ag-B, Ir-B, Ru-B, and Rh-B). The resultant meso-Pd-B alloy exhibits remarkable catalytic performance (1310 mA mg) in FAOR. Combined experimental results and density functional theory calculations indicate that the enhanced activity can be attributed to the electronic effect resulting from the alloying of Pd and B, which weakens the binding strength of toxic substances on the surface of the Pd catalyst. And the favorable mesoporous structure allows the catalyst to expose more catalytic active sites and accelerates the substance transfer efficiency.