Contribution of Interstitial Boron in a Boron-Incorporated Palladium Catalyst Toward Formate Oxidation in an Alkaline Direct Formate Fuel Cell
Sujik Hong, Sunki Chung, Jihyeon Park, Jin Pyo Hwang, Chang‐Hyun Lee, Sunghyun Uhm, Sungyool Bong, Jaeyoung Lee
Abstract
In this study, boron-incorporated palladium catalysts supported on carbon (PdBInc./C) were synthesized; they exhibited considerably improved catalytic activity for the oxidation of formate (HCOO–). Boron-induced lattice expansion and electronic modification of Pd were observed in this catalyst through various physicochemical analyses. Furthermore, the effective electronic modification between Pd and B was found to overcome the limitation due to the lattice expansion of Pd and the modification was confirmed from the downshift and broadening of the d-band center. The direction of electron transfer was observed from B to Pd. Based on the experimental results, it is possible to infer that PdBInc./C significantly contributes to the weakening of the hydrogen adsorption, which is regarded as a rate-determining step for the oxidation of HCOO–. As an anode electrode, PdBInc./C also showed an outstanding performance in a direct formate fuel cell owing to its modified electronic structure, which is considered an important property to facilitate hygroscopic fuel accessibility in a practical system.