Modification of the Surface Properties of Core-Shell Semiconductors and Their Effects on the Photodecolorization Activity and Adsorption

Shahab K. Asl

doi:10.4236/mrc.2017.61005

Abstract

Semiconductor-based photocatalysts have been extensively studied for oxidative photodestruction of organic pollutants in wastewaters, releasing non-toxic substances such as Azo dyes. Various synthesized catalyst specimens were characterized to determine the correlation between preparation conditions (catalyst type, dopant, microstructure, preparation routs, optical and physico-chemical properties) on the photocatalytic activity. Some researchers focused on the process parameters to optimize them to reach higher photoactivity. The specific surface areas, crystalline size, charge and pretreatment of the surface have significant effects on the physical and photocatalytic properties of the semiconductors. The surface sites of catalyst (TiO2) were modified by doping ZnS nanoparticles in the form of Core-Shell structure and the photocatalytic activities were determined by using color degradation and hydrogen production tests. The dye adsorption isotherms of photocatalyst were determined using UV-Vis spectroscopy. The specific surface properties were determined from BET, Zeta meter and Particle size analyzer tests. Photocatalytic decolorization of AR and water splitting test were applied to understand the relation between the surface properties and the photocatalytic activity. The result indicated that core-shell prepared samples had different surface suitable sites to cooperate in photocatalytic reaction.

Highlights

Photocatalysis has recently become a common green nano material
The surface sites of catalyst (TiO2) were modified by doping ZnS nanoparticles in the form of Core-Shell structure and the photocatalytic activities were determined by using color degradation and hydrogen production tests
The ZnS and TiO2 powders consist of cubic like and spherical particles, respectively but composite powders seem to be similar to core shapes

Summary

Introduction

Photocatalysis has recently become a common green nano material. Asl 66 tion in advanced oxidation processes was rapidly increased, because of world’s main problems, energy and fuel. The kinetic of heterogeneous catalysts like photocatalysts is included five steps. These are: 1) diffusion of reactants to the surface; 2) adsorption of reactants onto the surface; 3) reaction on the surface. This step in photocatalytic reaction proceed mainly by the contributions of active oxygen species, such as hydroxyl radical, OH−, superoxide radical, O

Methods

Results

Conclusion