Low-Coordinated Pd Site within Amorphous Palladium Selenide for Active, Selective, and Stable H₂ O₂ Electrosynthesis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• High-performance catalysts are crucial for efficient hydrogen peroxide (H2O2) electrosynthesis, but achieving high activity, selectivity, and stability remains a significant challenge.
• Low-coordinated metal sites are known to enhance electrocatalytic performance.

Purpose of the Study:

• To investigate the electrocatalytic performance of amorphous palladium selenide nanoparticles (a-PdSe2 NPs) for H2O2 electrosynthesis.
• To understand the role of low-coordinated Pd sites in a-PdSe2 NPs on H2O2 selectivity and productivity.

Main Methods:

• Synthesis of amorphous PdSe2 nanoparticles (a-PdSe2 NPs) supported on carbon (a-PdSe2 NPs/C).
• Electrochemical characterization including H2O2 selectivity and productivity measurements in various electrolytes (0.1 M KOH, 0.1 M HClO4, 0.1 M Na2SO4).
• Theoretical calculations to elucidate the mechanism of enhanced electrocatalysis.

Main Results:

• a-PdSe2 NPs/C demonstrated high H2O2 selectivity (>90%) across different pH conditions.
• Exceptional H2O2 productivities were achieved: ~3245.7, 1725.5, and 2242.1 mmol gPd-1 h-1 in KOH, HClO4, and Na2SO4, respectively.
• The disordered Pd sites and low-coordinated Pd atoms in a-PdSe2 NPs optimize oxygenated intermediate adsorption and suppress O-O bond cleavage, enhancing H2O2 yield.

Conclusions:

• Amorphous PdSe2 nanoparticles exhibit excellent pH-universal catalytic activity for electrochemical H2O2 synthesis.
• The unique structural features of a-PdSe2 NPs, particularly low-coordinated Pd sites, are key to boosting H2O2 selectivity and productivity.
• a-PdSe2 NPs/C show significant potential for practical, large-scale H2O2 electrosynthesis.