Sulfur Doping to Cu₃N Electrocatalyst Enhanced CO₂ Reduction to CH₄

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Metal sulfides are promising for CO2 reduction but face challenges due to electron repulsion.
• Nitrogen incorporation is a potential solution, but optimal ratios and product scope remain unclear.

Purpose of the Study:

• To synthesize copper sulfide (Cu2S) and copper nitride (Cu3N) composites with varied sulfur-to-nitrogen ratios.
• To enhance the electrochemical CO2 reduction reaction (CO2RR) towards methane (CH4) production.

Main Methods:

• Synthesis of Cu2S and Cu3N composites with controlled S/N ratios.
• Electrochemical characterization including Faradaic efficiency measurements.
• In-situ Fourier-transform infrared spectroscopy (FTIR) to study reaction intermediates.

Main Results:

• A Cu3N composite with 4.20 mol% sulfur showed superior Faradaic efficiency for CH4 production compared to bare Cu3N and Cu2S.
• In-situ FTIR indicated that sulfur introduction enhances electron donation to CO intermediates, favoring CH4 selectivity.
• The study achieved enhanced CO2 reduction to CH4, a valuable product.

Conclusions:

• Sulfide-nitride composite structures are effective electrocatalysts for CO2 reduction.
• Optimized sulfur doping in Cu3N is crucial for enhancing CH4 selectivity and production.
• This work demonstrates a viable strategy for generating valuable products from CO2 electroreduction.