Modification of Pd and Mn on the Surface of TiO₂ with Enhanced Photocatalytic Activity for Photoreduction of CO₂ into CH₄

The novel Pd- and Mn-comodified TiO₂ photocatalyst (TiO₂–Pd–Mn) was prepared via a simple sol–gel method. The introduced Pd and Mn existed as the −O–Pd–O– and −O–Mn–O– species on the surface of the photocatalyst. The band structure and density of states are studied by theoretical calculations, which is demonstrated by the experimental results. The modification with Pd and Mn ions results in the strong visible response and efficient separation of photogenerated carriers. Thus, the TiO₂–Pd–Mn exhibit improved photocatalytic activity compared with pure TiO₂, TiO₂–Pd, and TiO₂–Mn for photoreduction of CO₂ and H₂O into CH₄. It is an effective method on developing the highly active TiO₂-based materials by modification with double elements on the surface

Adjustment and Matching of Energy Band of TiO₂‑Based Photocatalysts by Metal Ions (Pd, Cu, Mn) for Photoreduction of CO₂ into CH₄

A series of the metal ions (Pd, Cu, and Mn) modified TiO₂ photocatalysts are synthesized via simple sol–gel method. Characterized by X-ray diffraction, Raman, UV–vis absorption spectra, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, time-resolved photoluminescence (PL) decay curves, and PL, it was revealed these introduced metal ions existed as O–Me–O species (Me: Pd, Cu, and Mn) on the surface of TiO₂. The corresponding theory calculation is used to investigate the electronic density of states and band structure of the metal ions (Pd, Cu, and Mn) modified TiO₂. The modified TiO₂ photocatalysts exhibit an improved photocatalytic performance on reduction of CO₂ and H₂O into methane (CH₄), attributed to the contribution of surface species by enhancing the visible absorption efficiently, separating charge carriers, and matching of the redox potential on the photoreduction of CO₂ into CH₄. This article could provide a wider understanding about the adjustment and matching of the energy level for the synthesis and design of functional materials with excellent photocatalytic performance