Dual-Enhanced Doping in ReSe₂ for Efficiently Photoenhanced Hydrogen Evolution Reaction

Area of Science:

• Materials Science
• Catalysis
• Electrochemistry
• Renewable Energy

Background:

• Rhenium dichalcogenides (ReX2, X = S or Se) show promise for photoenhanced hydrogen evolution reaction (PE-HER) due to unique properties.
• Current limitations include low concentrations of electrocatalytic active sites and inefficient hot electron injection.
• Optimizing these factors is crucial for advancing PE-HER catalyst performance.

Purpose of the Study:

• To achieve dual enhancement in ReSe2 nanosheets (NSs) for PE-HER by increasing active sites and improving hot electron utilization.
• To investigate the effects of moderate molybdenum (Mo) doping on ReSe2's physiochemical and catalytic properties.
• To systematically study the contributions of doping to catalytic performance, electrical conductivity, and solar spectral response.

Main Methods:

• Synthesis of Mo-doped ReSe2 nanosheets (Re1-x Mоx Se2).
• Characterization of material properties, including active site concentration, electrical conductivity, and band structure.
• Electrochemical testing for hydrogen evolution reaction (HER) under dark and simulated solar illumination (AM 1.5).

Main Results:

• Mo doping significantly increased the concentration of catalytically active sites and optimized the band structure of ReSe2.
• Optimal doping (Re0.94Mo0.06Se2) reduced the overpotential (η10) for HER from 239 mV to 174 mV in the dark.
• Under simulated sunlight, the overpotential was further reduced to 137 mV, achieving a total improvement of 102 mV.

Conclusions:

• Moderate Mo doping provides a dual enhancement strategy for ReSe2-based PE-HER catalysts, addressing limitations in active sites and electron injection.
• The optimized Re0.94Mo0.06Se2 catalyst exhibits superior PE-HER performance compared to undoped and other doped samples.
• This study offers a new avenue for developing high-efficiency PE-HER electrocatalysts based on ReSe2 and other layered transition metal dichalcogenides.