Surface-Dependent Intermediate Adsorption Modulation on Iridium-Modified Black Phosphorus Electrocatalysts for...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Two-dimensional black phosphorus (BP) shows potential for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalysis.
• BP's practical application in water splitting is limited by strong oxygen intermediate adsorption (OER) and weak hydrogen intermediate adsorption (HER), leading to high overpotentials.
• Existing BP catalysts require high overpotentials (450 mV for OER, 420 mV for HER) in alkaline conditions.

Purpose of the Study:

• To develop an efficient Ir-modified BP electrocatalyst for enhanced water splitting.
• To overcome the limitations of pure BP by optimizing adsorption energies for catalytic intermediates.
• To achieve superior and pH-universal water splitting performance compared to existing catalysts.

Main Methods:

• Rational introduction of nanosized iridium (Ir) as a modifier onto 2D black phosphorus (BP).
• Optimization of the exposed surface of the Ir-modified BP catalyst for electrolyte interaction.
• Electrochemical testing under acidic and alkaline conditions to evaluate water splitting performance.

Main Results:

• The Ir-modified BP catalyst exhibits favorable adsorption energies for catalytic intermediates.
• Achieved outstanding pH-universal water splitting performance, surpassing reported BP-based and commercial noble-metal catalysts.
• Required low overall cell voltages: 1.54 V (acidic) and 1.57 V (alkaline) to reach 10 mA cm⁻².

Conclusions:

• The Ir-modified BP catalyst demonstrates significant potential for practical electrocatalysis.
• Design strategies effectively decrease reaction intermediate adsorption energy barriers and enhance interfacial electron coupling.
• Provides new insights into surface-dependent activity enhancement mechanisms for heterostructured catalysts.