Complementary 3d-4d/5d Pairing in Medium-Entropy Sulfides for Bifunctional Water Electrolysis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Advanced electrocatalysts often incorporate multiple elements.
• Current methods lack a rational framework for functional complementarity, focusing on configurational entropy or empirical addition.
• Developing electrocatalysts with synergistic element interactions is crucial for enhanced performance.

Purpose of the Study:

• To propose and demonstrate the concept of complementary 3d-4d/5d element pairing in electrocatalysts.
• To synthesize a nanoporous medium-entropy multimetal sulfide, (CoNiMoW)S2, based on this design principle.
• To investigate the cooperative effects of different transition metals for improved electrocatalytic activity and stability.

Main Methods:

• Synthesis of a nanoporous medium-entropy multimetal sulfide (CoNiMoW)S2.
• Electrocatalytic performance testing for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER).
• Operando Raman spectroscopy and density functional theory (DFT) calculations to analyze catalytic mechanisms.

Main Results:

• The (CoNiMoW)S2 catalyst exhibits excellent bifunctional performance, with low overpotentials of 36 mV for HER and 120 mV for OER at 10 mA cm-2.
• The catalyst demonstrates outstanding operational stability exceeding 900 hours.
• Operando studies and DFT confirm the cooperative roles of 3d metals (Co, Ni) for active site generation and 4d/5d metals (Mo, W) for electronic modulation and structural stabilization.

Conclusions:

• Complementary 3d-4d/5d element pairing creates a synergistic catalytic system for efficient electrocatalysis.
• The rational design approach enables the development of highly active and durable electrocatalysts.
• This strategy offers a new pathway for designing advanced multimetal catalysts for energy conversion applications.