Semiconductor heterojunction photocatalysts: design, construction, and photocatalytic performances

Abstract

Semiconductor-mediated photocatalysis has received tremendous attention as it holds great promise to address the worldwide energy and environmental issues. To overcome the serious drawbacks of fast charge recombination and the limited visible-light absorption of semiconductor photocatalysts, many strategies have been developed in the past few decades and the most widely used one is to develop photocatalytic heterojunctions. This review attempts to summarize the recent progress in the rational design and fabrication of heterojunction photocatalysts, such as the semiconductor-semiconductor heterojunction, the semiconductor-metal heterojunction, the semiconductor-carbon heterojunction and the multicomponent heterojunction. The photocatalytic properties of the four junction systems are also discussed in relation to the environmental and energy applications, such as degradation of pollutants, hydrogen generation and photocatalytic disinfection. This tutorial review ends with a summary and some perspectives on the challenges and new directions in this exciting and still emerging area of research.

Enhanced visible-light-driven photocatalytic performance of mesoporous W-Ti-SBA-15 prepared through a facile hydrothermal route

“…E VB of WO 3 is much more positive than the E VB (+2.95 eV) of TiO 2 and hereby the holes on valence band of WO 3 tends to transfer across interfaces to that of TiO 2 [50]. Electrons stay on conduction band of WO 3 since the E CB of WO 3 is less negative than that of TiO 2 . Accordingly, the transfer and separation of produced charge carriers is successfully achieved, which is quite beneficial for enhancement of photocatalytic degradation efficiency.…”

“…Interestingly, sample 8%WS shows the highest adsorption capability among all samples containing SBA matrix because of the much more acidic nature of WO 3 than that of TiO 2 [9]. However, with the progress of photocatalysis, sample 8%WTS0.7 with both components of WO 3 and TiO 2 anchored on surface of SBA15 support tends to show a satisfactory photocatalytic performance that is even higher than 8%WS after 1.5 h. As a result, it is tempting to conclude that the composite is able to achieve excellent photocatalytic outcome under identical conditions, especially with the aid of an appropriate support like SBA15. It should be noted that photocatalytic ability of mechanically ground sample is much lower than that of sample 8%WTS0.7 and quite close to that of sample TS0.7 in Fig.…”

“…In recent years, semiconductor-based photocatalysis has aroused tremendous attention due to its potential applications in fields of environmental remediation and renewable energy supply through a green redox process under moderate conditions [1][2][3]. Among numerous semiconductors researched, titania (TiO 2 ) is the most popular one in virtue of the favorable physicochemical properties and outstanding photocatalytic performance in ultraviolet region [4].…”

CO2 Reduction: From the Electrochemical to Photochemical Approach

“…When two semiconductor materials are coupled together, they may form three possible types of heterostructures namely straddling gap (type I), staggered gap (type II), and broken gap (type III), depending on their relative band positions 186. Among them, the type II of heterosturcture is the most desirable since it promotes the spatial charge separation by transferring electrons to one material with the lower CB and holes to another material with the higher VB, as is shown in Figure 13 a 187. Coupling semiconductors with staggered gaps is an approach frequently adopted in photocatalysis.…”

Ag/Bi12O17Cl2 composite: A case study of visible-light-driven plasmonic photocatalyst

“…Over the past several decades, heterogeneous photocatalytic processes have drawn ever growing interest since they are able to find potential applications in energy storage and environmental remediation by means of absorbing and converting solar to chemical energy [1][2][3]. Bismuth oxychloride, a group of V-VI-VII ternary semiconductors, featured with a lamellar structure composed of [Cl-Bi-O-Bi-Cl] slices packed together with van der Waals force through chlorine atoms along the c-axis [4].…”