Synthesis Of ID Ag-Based Semiconductors With Enhanced Photocatalytic Activity

In recent years, people pay more and more attention to the environment problem and the environmental pollution has brought more negative impact on our life and health, especially the water pollution. Commom conventional wastewater treatment methods include physical adsorption method, chemical method and biodegradation method, these methods has yet made certain achievements, but there exist much more defects, such as low efficiency, high energy consumption, long processing cycle and limitied application, which determines us to find a technology with more security and stability of high efficiency, green environmental protection, energy saving, no secondary pollution to water. Within numerious wastewater treatment technology, photocatalysis technology gets scientific researchers'attention. Photocatalytic technology mainly uses solar light to radiate semiconductor materials, and then semiconductor materials can degrade pollutants effectively. The main part of this technology is semiconductor catalyst materials. The Ag-base semiconductor catalysts have been widely applied in the field of photocatalysis. In this paper, we precent a series of one-dimensional Ag-based compounds and its composites preparation and their photocatalytic performance studies, including the following three parts:1. Rapid formation of AgnX(X=S, Cl, PO4,C2O4) nanotubes via an acid-etching anion exchange reaction.This work presents a rapid nanotube fabrication method for a series of silver compounds AgnX, such as Ag2S, AgCl, Ag3PO4 and Ag2C2O4, from pregrown Ag2CO3 nanorod templates. The anion exchange process involved takes place in non-aqueous solutions just at room temperature and the reaction completes within 10 minutes. An acid-etching anion exchange reaction mechanism has been proved underneath the ransformation process from Ag2CO3 nanorods to AgnX nanotubes by the observation of an intermediate yolk-shell nanostructure. It has been found that the final structure of the products can be conveniently controlled by simply varying the concentration of HnX acids, and the organic solvents employed play a vital role in the formation of the nanotubes by controlling the diffusion rates of different species effectively. As demonstration, the as-prepared AgCl and Ag3PO4 nanotubes exhibit enhanced photocatalytic activity and favorable recyclability for the photodegradation of rhodamine B (RhB) under visible-light irradiation.2. Facile synthesis of Z-scheme Ag2CO3/Ag/AgBr ternary heterostructured nanorods with improved photostability and photoactivity.Ag-based compounds have been regarded as a new family of highly efficient visible-light-driven photocatalytic materials. However, in terms of photocorrosion nature of this type of photocatalyst, resulting in the serious deactivation, it is a huge challenge to develop simple and reliable strategies to synthesize Ag-based heterostructured nanostructures with good structural stability and high photoactivity. In this work, we have developed a facile visible-light induced reduction followed by an anion exchange, to prepare one-dimensional (1D) Ag2CO3/Ag/AgBr ternary heterostructured nanorods (HNRs) with tunable chemical compositions at room temperature. The as-obtained 1D Ag2CO3/Ag/AgBr HNRs exhibit significantly enhanced photostability and photocatalytic activity under visible-light illumination. The origin of enhanced photostability and photoactivity was further investigated by a radical-trapping test, and a possible Z-scheme photocatalytic mechanism was proposed.3. Synthesis of Ag2CO3/Ag/PANI nanocomposite with improved photocatalytic abilityIn this section, the ternary nanocomposites of Ag2CO3/Ag/PANI have been prepared via a two-step method, containing the light reduction of Ag on Ag2CO3 nanorods and subsequently chemisorption approach of excellent electrical conductivity performance of polymer polyaniline (PANI), combinating metal compounds and polymer materials with controble components. 1D ternary Ag2CO3/Ag/PANI heterogeneous material has higher photocatalytic activity than binary Ag2CO3/Ag under visible light radiation. We further investigated the origin of enhanced photostability and photoactivity by a radical-trapping test, and a possible photocatalytic mechanism was proposed.