Pt/MXene-enabled industrial flue gas waste heat-driven, dual-product selective photothermal catalytic reduction of CO2 with high efficiency

Abstract

This study employs a photodeposition method to load Ag and Pt nanoparticles onto the surface and interlayered structure of MXene, developing an efficient catalyst for CO₂ reduction in industrial flue gas. The catalyst exhibits excellent thermal catalytic performance within a low-temperature range of 60–100 °C, achieving CH₄ and CO production rates of 461 μmol g⁻¹ h⁻¹ and 86 μmol g⁻¹ h⁻¹, respectively, with a CH₄ selectivity of 84.3 %. This temperature range requires no additional heating, relying solely on residual heat from flue gas, which offers a distinct temperature advantage and high catalytic efficiency compared to most thermal and photothermal CO₂ reduction processes. Under simulated sunlight and at 100 °C, the production rates for CH₄ and CO are 34 μmol g⁻¹ h⁻¹ and 589 μmol g⁻¹ h⁻¹, respectively, with a CO selectivity of 94.5 %. Notably, the catalyst demonstrates dual-product selectivity under varying experimental conditions. Experimental characterization and density functional theory (DFT) calculations reveal the thermodynamic and kinetic mechanisms underlying the enhanced production rates and selectivity shifts in both thermal and photothermal catalysis, detailing the CO₂ reduction pathways and Gibbs free energy changes across conditions. This study not only provides a new approach for low temperature CO₂ catalytic reduction but also offers valuable insights into dual-product selectivity, demonstrating great potential for practical applications in industrial flue gas management.