Synthesis-Sequence-Controlled Surface and Electronic Structure in Pd-Ag-Ni(OH)₂/C Electrocatalysts for Efficient...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Direct formic acid fuel cells (DFAFCs) require efficient electrocatalysts for formic acid oxidation reaction (FAOR).
• Palladium-based nanocomposites are promising but require structural optimization for enhanced performance and durability.

Purpose of the Study:

• To investigate the impact of synthesis sequence and reduction pathway on PdAgNi-(OH)2/C nanocomposites for FAOR.
• To correlate structural and electronic properties with electrocatalytic activity and stability.

Main Methods:

• Screening of binary Pd/Ni-(OH)2 catalysts.
• Synthesis of ternary PdAgNi-(OH)2/C nanocomposites using sequential and simultaneous NaBH4 reduction.
• Structural characterization using XRD, TEM, XANES/EXAFS.
• Electrochemical evaluation of FAOR performance and stability.

Main Results:

• Optimal binary composition identified as Pd/Ni-(OH)2 (50:50 ratio).
• Simultaneous coreduction enhanced Pd-Ag-Ni interfacial coupling, Pd dispersion, and metal-oxide interactions.
• The Pd30Ag20Ni-(OH)2(50)/C catalyst prepared by simultaneous reduction showed a 23-fold increase in mass activity over commercial Pd/C.
• Improved catalyst stability under potential cycling was observed.

Conclusions:

• Synthesis sequence critically influences the electronic structure and FAOR performance of multicomponent Pd-based catalysts.
• Simultaneous reduction is an effective strategy for designing highly active and durable FAOR electrocatalysts.
• This study provides guidelines for developing advanced electrocatalysts for DFAFCs and other liquid-fuel energy conversion systems.