Spherical Ruthenium Disulfide-Sulfur-Doped Graphene Composite as an Efficient Hydrogen Evolution Electrocatalyst

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Economical green hydrogen production is vital for sustainable energy.
• High-performance catalysts are essential for efficient water splitting.
• Platinum-based catalysts are effective but costly for hydrogen evolution reaction (HER).

Purpose of the Study:

• To develop a cost-efficient and high-performance electrocatalyst for the hydrogen evolution reaction (HER).
• To investigate the catalytic behavior of spherical RuS2 on S-doped reduced graphene oxide (s-RuS2/S-rGO) in all pH conditions.
• To provide a low-cost alternative to platinum-based HER electrocatalysts.

Main Methods:

• Synthesis of spherical RuS2 on S-doped reduced graphene oxide (s-RuS2/S-rGO).
• Electrochemical characterization of HER performance in various pH electrolytes.
• Density functional theory (DFT) calculations to understand catalytic mechanisms.
• Fabrication and testing of a homemade electrolyzer using the novel catalyst.

Main Results:

• The s-RuS2/S-rGO catalyst exhibited excellent HER activity with low overpotentials (25 mV at 10 mA cm-2, 56 mV at 50 mA cm-2) and a Tafel slope of 29 mV dec-1.
• The catalyst demonstrated good stability for 100 hours in alkaline solutions, outperforming some existing catalysts.
• DFT calculations indicated that RuS2 active sites and S doping significantly contribute to HER activity, with properties comparable to platinum.
• A homemade electrolyzer with s-RuS2/S-rGO achieved a low voltage of 1.54 V at 20 mA cm-2 with stable operation for 24 hours.

Conclusions:

• The novel s-RuS2/S-rGO electrocatalyst is a highly effective and stable material for the hydrogen evolution reaction across all pH values.
• This catalyst presents a significant low-cost alternative to platinum for green hydrogen generation.
• The findings pave the way for the commercialization of affordable and efficient water-splitting technologies.