CdSeTe NSs/TiO2 NTs Photoelectric Catalytic Reduction of CO2

The TiO2 NTs was prepared by means of anodic oxidation method at the applied voltage of 20 V. The electrolyte consisted of 0.8 wt% NH4F, 1.6 wt% NaSO4, and 10 wt% PEG400. After 3 h anodization, it was rinsed with twice-distilled water and dried in a nitrogen stream. And then the amorphous TiO2 NTs were crystallized by annealing in oxygen atmosphere for 1.5 h at 500 degrees C at both heating and cooling rates of 1 degrees C.min(-1). Subsequently, the TiO2 NTs and CdSeTe precursor solution were placed in teflon-lined stainless reactor at 120 degrees C for 2 h. Then the CdSeTe modified TiO2 NTs were dried at 80 degrees C, at last, the modified TiO2 NTs was treated at 500 degrees C for 2 h under nitrogen atmosphere with heating and cooling rate of 2 degrees C.min(-1). The catalyst of CdSeTe NSs/TiO2 NTs was gained finally. According to the SEM (Scanning electron microscope), TEM (Transmission electron microscopy) and HRTEM (High resolution transmission electron microscopy) testing, it showed that the CdSeTe was sheet morphology and grew on the TiO2 NTs surface parallelly. XRD (X-ray diffraction) characterization revealed that CdSeTe NSs had preferential orientation along the (100) and (002) direction. Measured by UV-vis DRS (Ultraviolet-visible diffuse reflection spectrum), it got the band gap of the as-prepared catalyst material, 1.48 eV. Processing XPS (X-ray photoelectron spectroscopy) data by Linear extrapolation, we got its valence band located at 1.02 eV. So we could deduce that the conduction band minimum (CBM) was located at -0.46 eV. Under light irradiation, the photoelectrocatalytic reduction performance for CO2 had a significant improvement compared with TiO2 NTs, it expressed as the great increase of reduction current density. In the photoelectrocatalytic reduction of CO2 process, methanol was the major product identified by gas chromatography, and the excellent reduction mechanism was explained from the following three aspects: energy band match, electron high transport ability and the stability of catalyst material.