Chuong 5 ung dung xuc tac quang

Absorption of photons to create electron–hole pairs 2.. Separation and migration of the photogenerated electrons and holes; either migration to surface reaction sites iia, or recombin

Chương 5 ỨNG DỤNG XÚC TÁC QUANG TRONG XỬ LÝ MÔI TRƯỜNG

1 Absorption of photons to create electron–hole pairs

2 Separation and migration of the

photogenerated electrons and holes; either

migration to surface reaction sites (ii)a, or

recombination (ii)b

3 Surface chemical reactions, for which

surface character (active sites) and

quantity (surface area) are important

CARBON 49 (2011) 741

Improvement of photon absorption

Reduction of recombination

Activation of surface

Bases of photocatalytic enhancement

Main processes in semiconductor heterocatalysis

1 Introduction

Metal or Nonmetal doping Sensitization

Renewable and Sustainable Energy Rev 11 (2007) 401

Seong-Ju Hwang, et al Adv Funct Mater 2011, 21, 3111

J Phys Chem C 2007, 111, 7851-7861

Schematic band structures of a metal oxide

(NaTaO3) and metal (oxy)nitride (BaTaO2N)

Mechanism of dye-sensitized photocatalytic hydrogen production under visible light irradiation

Structural model for the CdTi nanohybrid

Improvement of photon absorption

Reduction of recombination

Metal deposition particles can act

as electron trapping to reduce the

recombination rate of photogenerated electron-hole pairs

Applied Catalysis A: General 325 (2007) 1

Reducing of particle size Metal deposition

Decreasing particle size reduces the probability of

electron–hole recombination due to reduced

migration distances and fewer defects

CARBON 49 (2011) 741

Activation of surface

Increase of active sites Increase of surface area

porous materials

Chem Mater 2010, 22, 612–623

Schematic illustration of overall water splitting

on a heterogeneous photocatalyst

TEM micrograph of TiO2 nanoparticles in

a microporous region of activated carbon

CARBON 49 (2011) 741

CƠ CHẾ PHẢN ỨNG XÚC TÁC QUANG TRONG

XỬ LÝ CÁC HỢP CHẤT HỮU CƠ

1 Types and composition of photocatalyst

2 Influence of substituent group

3 Light intensity and wavelength

Effect of operating parameters on the degradation of pesticides and phenols

4 Pollutant type and concentration

5 Catalyst loading

6 Medium pH

7 Synthesis technique and calcination temperature

8 Doping and mixed semiconductor

9 Interfering substances

10 Oxidants/electron acceptor

11 Mode of application: suspended vs immobilized system