Interfacial effects of MnOx-loaded TiO2 with exposed {001} facets and its catalytic activity for the photoreduction of CO2

Abstract

Herein, anatase TiO₂ with different percentages of exposed {001} and {101} facets was prepared, and subsequently, Ag and MnO_x were co-loaded on these TiO₂ facets through a classical photodeposition method; the loaded TiO₂ samples were labeled as Ag–TiO₂–MnO_x (N%), where N% denotes the percentage of the exposed {001} facets. The as-prepared samples were analyzed via scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectroscopy (DRS), and the photocatalytic reduction of CO₂ was carried out. The results showed that Ag–TiO₂–MnO_x (40%) exhibited the highest photocatalytic activity among the other dual-loaded samples and pure TiO₂. The XPS spectra demonstrated that Ti–O–Mn and Ti–O–H bonds were formed at the interfaces of the cocatalyst-TiO₂. The PL and VB spectra revealed that the chemical bond (Ti–O–Mn) at the Ag–TiO₂–MnO_x (40%) interface greatly increased the hole mobility rate and the photoinduced carrier separation efficiency that resulted in higher catalytic activity for the photoreduction of CO₂.