Efficient photothermal mineralization of toluene over MnCo2O4 with different exposed facets: Revealing the role of oxygen vacancy and photo-/thermo- synergistic mechanism

Modulating oxygen vacancies through facet engineering is a potential strategy to enhance activity of photo-/thermo- synergistic catalysis for toluene mineralization. Hence, we synthesized MnCo2O4 catalysts with exposed {01−1} facets (MCO-R), {1−1−2} facets MCO-S), and {1−10} facets (MCO-C), in which the MCO-R with the highest oxygen vacancy concentration exhibited the highest toluene conversion (95.8 %) and CO2 yield (85.5 %) under the full-spectrum light irradiation. The results of various characterizations and DFT calculations confirmed that the oxygen vacancy could accelerate the activation of lattice oxygen and molecule oxygen, thereby enhancing the photothermal catalytic toluene activity of MnCo2O4. Meanwhile, the results of performance evaluations identified that the efficient photothermal mineralization activity of toluene was induced by the photo-/thermo- synergistic catalysis. Besides, the reaction pathway studies by In-situ DRIFTS tests revealed the key role of oxygen vacancy and photo-/thermo- synergistic effects in the reaction progress of photothermal mineralization of toluene over MnCo2O4.