Synthesis And Visible Light-Driven Photocatalytic Performances Of Silver Halide/Conducting Polymer Nanocomposites

Due to the important role played by Photocatalytic technology in photocatalytic water split to evolve hydrogen, photocatalytic degradation of pollutes and photocatalytic sterilization of bacterial, taking advantage of the it has become a meaningful method in resolving energy crisis and environment problems. Furthermore, visible light-driven photocatalysis, which can make the most of the clean sunlight, attract much attention. The applications mentioned above depend on the effective selection and controllable synthesis of highly-efficient and stable visible light photocatalysts.The photosensitized AgX can be transformed into a series of highly-efficient and stable visible light photocatalysts by synthesizing binary and ternary composites such as Ag/AgX, SC/AgX, Ag/AgX/AgX. In this paper, Ag/PPy colloid, AgCl/PPy and AgCl/PANI nanocomposites were studied in detail, including the synthesis of composite sol conditions, visible light photocatalytic performance and principles of AgX/PPy and AgCl/PANI composite material. It includes the four parts as follows.(1) Microwave assisted preparation of Ag/PPy composite colloidFirst, using the Ag/PPy colloid which contains Ag+ as the Ag resource, the original time of existing methods of synthesizing Ag/PPy can continue more than 48h. While by changing the synthesis conditions and introduce microwave method, Ag/PPy composite colloid can be quickly and easily prepared, which can make the formation time shorten to less than 3h. On the basis, the impacts on the products of the reaction temperature, the reaction time and the original concentration of reactant are studied as well, in order to form a better and quicker condition.(2) Synthesis and visible light catalytic performance of AgX/PPy composite nanometer materialsSecond, by inttoducing different halogen icons(X-) such as Cl-, Br- and I- into the fresh Ag/PPy blue composite colloid containing excessive Ag+, three composites (AgCl/PPy, AgBr/PPy and Agl/PPy) are prepared. The result of XRD and FTIP proved the existence of AgX and PPy and SEM and TEM displayed that the size of the composites can be nanometer, which is apparently smaller than that of pure AgX prepared in the same condition.Nano-sized AgX/PPy composites were prepared by using methyl orange (MO) solution as simulation wastewater, with high-pressure mercury lamp or xenon lamp and a filter, whose wavelength isλ≥400nm (in order to ensure that the samples accept visible light) as the light source, we use AgX/PPy photocatalyst photocatalytic degrade methyl orange (MO) solution to test the visible light photocatalytic performance of AgX/PPy composite nano-sized material. So, provided the conclusion is:in AgX/PPy composites materials, the visible light photocatalytic performance of AgCl/PPy composites is best, its photocatalytic efficiency and stability are significantly better than AgBr/PPy composites. AgBr/PPy composites has good stability in the first five cycles, then its photocatalytic performance obvious decay in the last five cycles, and its stability is inferior than pure AgBr. The visible light photocatalytic performance of AgI/PPy composites and AgI are undesirability and inferior.(3) Mechanism involved in the photocatalytic degradation of AgX/PPy compositesThe research and accurate achieve light catalytic mechanism is very important for optimize light catalytic conditions and improve the effect of light catalysis. In this paper, firstly through the UV-Vis absorption spectra of AgCl, AgBr, AgCl/PPy, AgBr/PPy confirm that visible light catalytic process of silver halides is a photoreduction process. On this basis, through the hydrogen peroxide (H2O2, electron scavenger) or methanol (CH3OH, hole scavenger) to join and addition amount for visible light the influence of catalytic speed, further confirm that visible light catalytic degrade MO process of AgX system is a photoreduction process.(4) Synthesis and visible light catalytic performance of AgX/PANI composite nanometer materialsFinally, through situ polymerization synthetize the AgCl/PANI composites in acid conditions with existence of HCl. The PANI can be well distributed around the surrounding and the surface of the AgCl particles,which are the size of several hundred nanometers. Then, through the experiment of photocatalytic degradation methyl orange (MO) solution show that: in the AgCl/PANI composites, when the ratio of aniline is 1%, the composite material has the best photocatalytic performance.