The structure modification and activity improvement of Pd–Co/C electrocatalysts by the addition of Au for the oxygen reduction reaction

Abstract

In this study, Pd 75 Co 25Àx Au x /C ternary catalysts with varying x content are synthesized by the deposition-precipitation approach with hydrogen reduction at 390 K for the oxygen reduction reaction (ORR). The roles of Au in the modification of structures, surface species and electrochemical properties of PdCo/C catalysts are investigated. X-ray diffraction results reveal that although the low reduction temperature does not benefit the Co alloying with Pd, Pd-Au alloys are preferentially formed. Moreover, it confirms that the incorporation of Au into a Pd-Co system contributes to the generation of inhomogeneous alloy structure. Fine structural details determined by X-ray absorption spectroscopy indicate that Au addition improves the heteroatomic intermixing extent of alloy nanocatalysts, especially for Pd 75 Co 10 Au 15 /C (Au 15 ) catalysts. Surface characterization by temperature programmed reduction suggests that a Pd-rich surface gradually changes to Pd, Au and alloy mixed surfaces when the Au content is larger than 15 at%. Regarding the electrochemical results, Au 15 displays the superior ORR performance among all samples due to the improved heteroatomic intermixing extent, large electrochemical surface area and multiple coexisting surface species. Furthermore, it also displays a better stability than Pd/C and Pd 75 Co 25 /C catalysts after accelerated durability tests.

Electroformation of Pd‐modified Thin Film Electrocatalysts Using E‐ALD Technique

“…The additional peaks at lower 2 θ may indicate the elemental Bi for the corresponding deposits. Conclusively, the addition of adatoms tailored the structure of Pd similar to the literature [94] and in accordance with the CV results.…”

Ligand-Exchange-Assisted Layer-by-Layer Assembly of Au–Pt Bimetallic Nanocomposite Films and Their Electrocatalytic Activities for Hydrogen Evolution Reaction

“…For example, bimetallic catalysts with transition metals (Cr, Mn, Fe, Co, Ni, Cu, and Zn) or noble metals (Ru, Pd, Ag, and Au) have been used to harness their electronic and bifunctional effects. ,,, Among such frameworks, Au–Pt bimetallic electrocatalysts have been reported to exhibit enhanced stability and activity. The addition of Au endows bimetallic catalysts with several advantages, such as decreased d -orbital vacancy of Pt for the modification of the adsorption energy of reactants, increased Pt oxidation potential for long-term stability, and enhanced electron transfer . Various synthetic approaches such as seeded growth, , galvanostatic deposition, − surface dealloying, − and electrodeposition − have been utilized to prepare alloys, heterostructures, and core–shell bimetallic catalysts.…”