Constructing Hydrogen Migration Channel from Atomic Clusters to Single Atom for Superior Electrocatalytic Hydrogen...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Proton exchange membrane water electrolyzers (PEMWE) require highly active and durable cathode catalysts, but noble metal usage (e.g., platinum) presents a significant challenge.
• The Sabatier principle often limits the independent optimization of hydrogen evolution reaction (HER) intermediates, hindering catalyst performance.
• Developing cost-effective catalysts with minimal noble metal loading is crucial for practical green hydrogen production.

Purpose of the Study:

• To design and synthesize a novel Pt-based sub-nanometric catalyst with coexisting single atoms and atomic clusters.
• To investigate the dual-active-site architecture for independent optimization of hydrogen (H*) formation and recombination kinetics.
• To demonstrate enhanced activity and durability in PEMWE for efficient green hydrogen production.

Main Methods:

• Synthesis of Pt-based sub-nanometric catalysts anchored on sulfur-doped carbon.
• Incorporation of a secondary transition metal (e.g., Mn) to tune interfacial charge distribution and work function.
• Characterization using operando experiments and theoretical calculations to confirm reaction mechanisms.
• Electrochemical testing of catalyst performance in a proton exchange membrane water electrolyzer.

Main Results:

• The dual-active-site catalyst architecture successfully decoupled H* formation and recombination kinetics.
• Introduction of Mn regulated Pt cluster properties, promoting H* formation and migration.
• Electron-deficient Pt single atoms adjacent to clusters facilitated H* recombination.
• A catalyst with 3.6 wt% Pt loading achieved a mass activity of 14.48 A mg^-1 at 15 mV, 41-fold higher than commercial 40wt% Pt/C.
• The catalyst demonstrated exceptional activity and stability in a PEMWE with only 10% of the benchmark Pt loading.

Conclusions:

• The developed Pt-based sub-nanometric catalyst with coexisting single atoms and atomic clusters offers a new paradigm for designing efficient HER catalysts.
• This dual-active-site strategy effectively overcomes the Sabatier principle limitation, enabling superior performance.
• The catalyst represents a critical advancement for practical green hydrogen production by significantly reducing noble metal requirements.
• Operando studies and theoretical calculations provided direct evidence of H* dynamics, offering insights for future catalyst rational design.