Highly Uniform Nanodiamond-Graphene Composites Microspheres for Electrocatalytic Hydrogen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Energy Conversion

Background:

• The clean hydrogen energy economy requires cost-effective and efficient catalysts for the hydrogen evolution reaction (HER).
• Two-dimensional materials show promise, but current synthesis methods are often time-consuming, complex, and inefficient.
• There is a need for improved catalytic materials for sustainable energy applications.

Purpose of the Study:

• To evaluate the catalytic performance of nanodiamond/graphene composite microspheres (ND-GCSs) for the HER.
• To demonstrate an improved synthesis method for uniform particle size and high yield of ND-GCSs.
• To explore the potential of this novel composite for broader energy storage and catalysis applications.

Main Methods:

• Microwave-irradiation synthesis of nanodiamond/graphene composite microspheres (ND-GCSs).
• Modification of the synthesis process to enhance particle size uniformity and yield.
• Electrochemical characterization of ND-GCSs assembled on screen-printed carbon electrodes (SPCEs) for HER activity.

Main Results:

• The prepared ND-GCSs@SPCE exhibited significant catalytic activity for HER, with an onset potential shift to approximately -450 mV.
• A small Tafel slope of approximately 85 mV/decade and a drastic decrease in charge transfer resistance (to ~265 Ω) were observed.
• The electrocatalyst demonstrated excellent long-term stability for HER applications.

Conclusions:

• Nanodiamond/graphene composite microspheres synthesized via microwave irradiation are highly effective HER electrocatalysts.
• The optimized synthesis yields a material with superior catalytic performance and stability.
• This novel composite structure holds potential for diverse applications beyond HER, including batteries and supercapacitors.