title: Coupled Heterojunction Sn₂Ta₂O₇@SnO₂: Cooperative Promotion of Effective Electron-Hole Separation and Superior Visible-light Absorption.
abstract: In this work, a novel heterostructure integrated by two wide-band gap semiconductors, SnO2 and Sn2Ta2O7, is successfully prepared via a hydrothermal approach. Hollow Sn2Ta2O7 spheres were first formed, and small SnO2 particles were then well-dispersed onto the outside surface of the spheres, forming a p-n heterostructure. This heterostructure exhibits a higher potential edge that yielded enhanced photoredox ability. Further, the heterostructure is of Z-type with a consistent internal electric field direction, which effectively separates the photogenerated electron-hole pairs. Although both component semiconductors do not absorb visible light, the resulted p-n heterostructure is surprisingly observed to show an outstanding photocatalytic performance under visible light illumination. Such a visible light response is concluded to be the consequence of the impurity band formed by Sn(2+) doped in SnO2 and Sn(4+) in Sn2Ta2O7 via in situ redox. The existence of coupled Sn(2+) and Sn(4+) ions in p-n heterostructure is responsible for the absence of defects and the regenerated catalytic activities. The findings reported here may provide an approach to fabricate the new types of photocatalysts with a synergetic promotion for visible light absorption and sustained photocatalytic activities by coupling different wide-band semiconductors.
authors.affiliation: †School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot City 010021, People's Republic of China.
authors.forename: Junyu
authors.initials: J
authors.lastname: Lang
authors.affiliation: †School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot City 010021, People's Republic of China.
authors.forename: Congyan
authors.initials: C
authors.lastname: Li
authors.affiliation: †School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot City 010021, People's Republic of China.
authors.forename: Shuwei
authors.initials: S
authors.lastname: Wang
authors.affiliation: †School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot City 010021, People's Republic of China.
authors.forename: Juanjuan
authors.initials: J
authors.lastname: Lv
authors.affiliation: †School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot City 010021, People's Republic of China.
authors.forename: Yiguo
authors.initials: Y
authors.lastname: Su
authors.affiliation: †School of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot City 010021, People's Republic of China.
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Wang
authors.affiliation: ‡National Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Chemistry College, Jilin University, Changchun 130023, People's Republic of China.
authors.forename: Guangshe
authors.initials: G
authors.lastname: Li
keywords: Sn2Ta2O7@Sn2O; heterostructures; photocatalysis; self-doping; visible light