Synthesis And Photocatalytic Properties Of Clay-based Plasma Composite

Photocatalyst can be use to split water into hydrogen, photoreduced CO2and photodegrade organic pollution and so on. Therefore, the photocatalytic technology has prospect of application in solving the problem of energy shortage, global warming and environment pollution. TiO2is the most widely used photocatalyst due to its high catalytic activity, good chemical stability and non-toxicity, etc. unfortunately, it is activated only under UV light irradiation because of its large band gap. Moreover, the TiO2powder has small surface area leading to a low adsorption capacity for much diluted solutions, which take a low photocatalytic effect for low concentration wastewater treatment. And the photocatalyst in suspended system was difficult to separate from aqueous solution. These questions hindered its practical applications. Therefore, the development of new visible light-driven photocatalyst and immobilized the catalyst are essential to the control of environment pollution and the use of sustainable energies.The plasmonic photocatalyst combining the surface plasmonic resonance (SPR) properties of noble metal nanoparticles and the photocatalytic properties of semiconductors, which is expect to improve the photocatalytic activity and increase the utilization ration of visible light. Clays can serve as the host materials for catalysts because of their large surface area for adsorption of organic pollutants as well as their abundance and low cost. In this paper, Ag/AgX plasmonic photocatalyst supported on clays were studied, the photocatalyst can take full advantage of the visible light response of the plasmonic photocatalst to improve the utilization of sunlight, and can use the particular structure properties of clays to increase the surface area of the photocatalyst and the solid-liquid separation efficiency as well as avoid the formation of macroscopic aggregates of photoactive particles and protects the photocatalyst particles from erosion or washing in the photodegradation process. The present work fabricated series of visible light driven photocatalysts with various structures. The microstructure properties and the photocatalytic activities of the prepared photocataltst were measured by means of characterization methods. This work has valuable exploration in theory and practical application. The main points of the present work could be summarized as follows:In this paper, the TiO2/rectorite composites were successfully prepared by a facile and low-cost sol-gel technique at low temperature, Ag-AgCl particles were then loaded on the TiO2/rectorite to obtain the Ag-AgCl-TiO2/rectorite composite. The as-prepared photocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (HRTEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), laser Raman spectroscopy (Raman) and UV-vis diffuse reflectance spectrum (UV-vis DRS). The photocatalytic activities of the as-prepared photocatalysts were evaluated by the degradation of acid red G (ARG) and4-nitrophemol (4-NP) in aqueous solution under visible light irradiation. The relationship between the photocatalytic activity and the structural features of the prepared catalysts was investigated through a systematic characterization analysis. A possible photocatalytic mechanism was discussed through UV-vis spectrum analysis and active species analysis in the photocatalytic reaction. The results indicated that the photoreduction method can reduce partial ions to Ag0species, which can effectively improve the absorption of visible light. And the clay as the supports of the composites can improve the adsorption capacity of organic pollutants. Therefore, this paper explores a new way to prepare a visible light responsive photocatalyst with high adsorption.Conventional TiO2photocatalyst requires near-ultraviolet irradiation for effective photocatalysis and difficult to separate from aqueous solutions thereby severely limiting its practical application. At first, TiO2immobilized on attapulgite was prepared by sol-gel method, and then deposited Ag-AgCl on the surface of TiO2/attapulgite by a precipitation and photoreduction method to obtain the Ag-AgCl-TiO2/attapulgite photocatalyst. The composite were characterized by some characterization methods. The prepared photocatalyst exhibits an efficient visible light photocatalytic activity for degradation of Rhodamine B and has a higher adsorption and photocatalytic activity than the Ag-AgCl and TiO2/attapulgite powders under the same condition. The experiments confirmed the composite was beneficial to enhancing the adsorption activity and the utilization of sunlight, which has a beneficial effect on the practical application of photocatalytic technology.Ag-AgBr/clay composite was synthesized and characterized by XRD, SEM, TEM, XPS and UV-vis DRS methods. And the strategy for the fabrication of Ag-AgBr/clay composite was proposed. The visible light driven photocatalytic activity of this composite material was investigated by the photocatalytic decomposition of azo dyes and the photocatalytic mechanism of the reaction was also discussed. It was obvious that the photocatalytic activity of Ag-AgBr/clay was higher than that of Ag-AgBr under the same conditions. The results indicate that the surface plasmon resonance of Ag can enhance the visible light adsorption of photocatalyst. The clay function as a substrate for Ag-AgBr particles can stabilized photocatalyst to avoid catalyst loss and thus improve the utilization of the catalyst. Moreover, the specific surface area, the active sites, the separation of electron-holes and the adsorption properties are improved by the carrier. The performance photocatalytic activity of the composite can be attributed to the synergetic effect of the visible light adsorption of the plasmon materials and the large specific surface area of the clay.