In Situ Creation of Surface Defects on Pd@NiPd with Core-shell Hierarchical Structure Toward Boosting...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Understanding catalyst surface structural evolution is crucial for structure-activity relationships.
• Developing efficient dual-functional catalysts for hydrogen and oxygen reactions is a key challenge.

Purpose of the Study:

• To develop a novel dual-functional catalyst with a core-shell hierarchical structure.
• To investigate the role of surface defects in enhancing electrocatalytic activity for HER and OER.

Main Methods:

• Surface alloying strategy using selective crystal growth, cocrystallization, self-assembly, and reduction.
• Electrochemical characterization for hydrogen generation reaction (HER) and oxygen generation reaction (OER) performance evaluation.
• Density functional theory (DFT) calculations to elucidate reaction mechanisms.

Main Results:

• The Pd@NiPd catalyst with in situ created surface defects showed excellent HER and OER activity in alkaline media.
• The optimal Pd@NiPd-2 catalyst achieved significantly lower overpotentials for HER (18 mV vs. 43 mV for Pt/C) and OER (210 mV vs. 430 mV for RuO2).
• DFT calculations confirmed that surface defects reduce energy barriers for H2O adsorption/dissociation in HER and O* to OOH* conversion in OER.

Conclusions:

• Engineered surface defects on Pd@NiPd core-shell catalysts significantly enhance electrocatalytic activity for HER and OER.
• The synergistic effect of adjacent Pd sites and reduced energy barriers contribute to the catalyst's superior performance.
• This work provides a paradigm for designing efficient catalysts by controlling surface structural evolution.