Light-Driven Syngas Production over Defective ZnIn₂ S₄ Nanosheets

Area of Science:

• Materials Science
• Catalysis
• Renewable Energy

Background:

• Photocatalytic conversion of carbon dioxide (CO2) into syngas (CO and H2) offers a sustainable route for chemical feedstock production and greenhouse gas mitigation.
• Traditional photocatalysts often rely on expensive noble metals or exhibit low efficiency, limiting practical applications.

Purpose of the Study:

• To investigate the impact of sulfur vacancies on the photocatalytic performance of ZnIn2S4 for CO2 reduction.
• To develop a highly efficient, noble-metal-free photocatalyst for syngas production.

Main Methods:

• Synthesis of sulfur-deficient ZnIn2S4 (V_S-ZnIn2S4) nanosheets.
• Characterization of material properties, including photoabsorption, charge separation, and CO2 adsorption.
• Evaluation of photocatalytic activity for CO2 reduction into syngas under light irradiation.

Main Results:

• Sulfur vacancies significantly enhance photoabsorption, electron-hole separation, and CO2 adsorption in ZnIn2S4.
• V_S-ZnIn2S4 demonstrates a ≈4.73-fold increase in syngas yield compared to pristine ZnIn2S4.
• Achieved a high syngas yield of 63.20 mmol g⁻¹ after 12 hours, with a modified CO/H2 ratio of 1:1, outperforming noble metal-based catalysts.

Conclusions:

• Sulfur vacancies are crucial for optimizing the photocatalytic activity and selectivity of ZnIn2S4 for syngas production.
• Defective ZnIn2S4 presents a promising, cost-effective alternative for light-driven CO2 conversion into valuable chemical feedstocks.