Insight Into the Porphyrin-Modulated Interfacial Charge Transfer Kinetics Behavior of Molybdenum Disulfide...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Electrocatalytic water splitting for hydrogen generation is a key sustainable energy strategy.
• Transition metal dichalcogenides, particularly MoS₂, are promising electrocatalysts but often suffer from mixed-phase issues.
• Achieving pure metastable MoS₂ phases for superior performance remains a challenge.

Purpose of the Study:

• To enhance the catalytic activity of semiconducting 2H-MoS₂ for hydrogen evolution reaction (HER).
• To investigate the effect of 5,10,15,20-Tetrakis(4-hydroxyphenyl)porphyrin (THPP) as an electron donor on MoS₂ catalytic properties.
• To understand the charge transfer dynamics at the microscopic level.

Main Methods:

• Modification of 2H-MoS₂ with THPP.
• Synthesis of 2H-MoS₂/NiS₂/THPP composite catalyst.
• In situ scanning photoelectrochemical microscopy (SPECM) for investigating charge transfer kinetics.

Main Results:

• The THPP modification shifted the catalytic properties of 2H-MoS₂ towards the metallic 1T phase.
• 2H-MoS₂/NiS₂/THPP exhibited a charge transfer rate constant of 0.35 × 10^-2 cm s^-1, over three times higher than 2H-MoS₂/NiS₂.
• Enhanced charge transfer kinetics were attributed to THPP acting as a charge transporting mediator, improving charge separation and reducing recombination.

Conclusions:

• THPP effectively modifies 2H-MoS₂, significantly boosting its electrocatalytic performance for hydrogen generation.
• The porphyrin mediator plays a crucial role in accelerating charge transfer and enhancing overall catalytic efficiency.
• This approach offers a promising strategy for developing advanced semiconductor electrocatalysts for clean hydrogen production.