# Au LSPR Effect Enhanced R‐CeO2/G‐C3N4 S‐scheme Heterojunction for Accelerating CO2 Photoreduction Performance

## TL;DR

This study creates a new photocatalyst using gold's plasmon effect to boost CO2 conversion into CO, achieving high efficiency and stability.

## Contribution

The novel use of Au LSPR in an S-scheme heterojunction significantly enhances CO2 photoreduction performance.

## Key findings

- The CO yield of CAC-2 is 50.58 µmol·g⁻¹·h⁻¹, 6.7 times higher than R-CeO2.
- Au nanoparticles improve carrier separation and lower the *COOH formation energy barrier.
- CAC-2 shows the largest specific surface area and best CO2 adsorption capacity.

## Abstract

Excellent CO2 adsorption ability and fast photogenerated carriers’ supply are vital conditions for efficient CO2 photoreduction. In this paper, Au localized surface plasmon resonance (LSPR) has been successfully applied in a R‐CeO2/g‐C3N4 S‐scheme heterojunction photocatalyst for CO2 photoreduction. R‐CeO2/Au/g‐C3N4 (CAC‐2) exhibited excellent CO2 photoreduction performance and great stability. The CO yield over CAC‐2 is about 50.58 µmol·g−1·h−1 under UV–vis light irradiation, which is about 6.7 and 6.0 times higher than that of R‐CeO2 and g‐C3N4, respectively. FDTD simulation, DFT calculation and photoelectrochemical tests together prove the introduction of Au NPs not only enhances the photogenerated carriers’ separation efficiency, but also decreases the formation energy barrier of the important intermediate *COOH, which is beneficial for the CO2 photoreduction to CO. N2/CO2 adsorption‐desorption curves indicated that the CAC‐2 ternary composite had the largest specific surface area and the best CO2 adsorption capacity. Meanwhile, DFT calculation confirmed that the reduction sites of the CAC‐2 had the highest electron density, which can synergistically enhance the CO2 photoreduction activity. The improvement of photocatalytic performance can be attributed to the synergistic enhancement of Au LSPR effect and S‐scheme heterojunction at the interface. Based on the in situ FTIR, in situ ESR, and 13C isotope tracer experiment, a potential LSPR effect‐enhanced S‐scheme heterojunction catalytic mechanism has been provided, which may represent a significant advancement in the field.

This study develops an Au localized surface plasmon resonance (LSPR) enhanced S‐scheme heterojunction between oxygen vacancy‐rich CeO2 (R‐CeO2) and graphitic carbon nitride (g‐C3N4) for efficient CO2 photoreduction. The ternary catalyst achieves high CO yield by synergistically improving carrier separation and reducing energy barriers, as validated through experiments and simulations.