Ultrathin polymeric carbon nitride loaded AuCu alloy cocatalysts for efficient photocatalytic CO2 reduction to syngas

Abstract

The efficient photocatalytic conversion of CO₂ has garnered considerable interest as a sustainable approach to address increasing CO₂ emissions. A crucial aspect of this process is the enhancement of photogenerated carrier separation and transport efficiency, which directly impact catalytic performance. In view of this, a polymeric carbon nitride (PCN) integrated with a gold–copper alloy co-catalyst (AuCu-PCN) was designed and fabricated in this study for the effective conversion of CO₂ to syngas, achieving excellent photocatalytic efficiency. The results show that AuCu alloy nanoparticles, as active sites for the reaction, not only promote the separation of photogenerated electron–hole pairs, but also synergistically contribute to the photocatalytic CO₂ reduction. Adjusting the AuCu ratio in AuCu alloys significantly improves the separation and migration of photogenerated carriers in PCN substrates, as well as significantly improves the CO and H₂ yields. The precipitation rates of H₂, CO and CH₄ produced by AuCu-PCN photocatalysts during the reaction were 621.87 μmol g⁻¹ h⁻¹, 78.26 μmol g⁻¹ h⁻¹ and 9.09 μmol g⁻¹ h⁻¹, respectively. These values indicate that the CO, CH₄ and H₂ yields of the AuCu-PCN photocatalysts are significantly higher compared to PCN, with the CO yield being six times higher than that of PCN. The present study focuses on photocatalytic CO₂ reduction for syngas production, offering unique insights and innovative approaches that provide new perspectives for the advancement of this field.