Enhanced photocatalytic activity of Ce-doped Zn-Al multi-metal oxide composites derived from layered double hydroxide precursors

Jianyao Zhu; Zhiliang Zhu; Hua Zhang; Hongtao Lu; Yanling Qiu; Linyan Zhu; Stephan Küppers

doi:10.1016/j.jcis.2016.07.051

Enhanced photocatalytic activity of Ce-doped Zn-Al multi-metal oxide composites derived from layered double hydroxide precursors

J Colloid Interface Sci. 2016 Nov 1:481:144-57. doi: 10.1016/j.jcis.2016.07.051. Epub 2016 Jul 21.

Authors

Jianyao Zhu¹, Zhiliang Zhu², Hua Zhang¹, Hongtao Lu¹, Yanling Qiu³, Linyan Zhu⁴, Stephan Küppers⁵

Affiliations

¹ State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China.
² State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China. Electronic address: zzl@tongji.edu.cn.
³ Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092, China.
⁴ State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092, China; ZEA-3, Research Center Jülich, Jülich 52425, Germany.
⁵ ZEA-3, Research Center Jülich, Jülich 52425, Germany.

PMID: 27474815
DOI: 10.1016/j.jcis.2016.07.051

Abstract

In this work, a series of novel Zn-Al-Ce multi-metal oxide (Zn-Al-Ce-MMO) photocatalysts with different Ce doping contents were prepared by calcination of Ce-doped Zn-Al layered double hydroxide (Zn-Al-Ce-LDH) precursors at various temperatures in air atmosphere. The synthesized Zn-Al-Ce-MMO materials were characterized by XRD, FTIR, TGA, BET, SEM, TEM, XPS and UV-vis DRS. The photocatalytic activities of the Zn-Al-Ce-MMO materials were evaluated by the photodegradation of rhodamine B (RhB) dye and paracetamol in aqueous solution under simulated solar light irradiation. The result of photodegradation of RhB showed that the Zn-Al-Ce-MMO samples exhibit much higher photocatalytic activity than that of Zn-Al-MMO, and the optimal Ce doping content is 5% of mole ratio (nCe/n(Zn+Al+Ce)). The enhanced photocatalytic activity of the Zn-Al-Ce-MMO was mainly attributed to the increasing in the separation efficiency of electrons and holes. The effect of calcination temperature was also studied. The photocatalytic activity of Zn-Al-Ce-MMO increased with increasing calcination temperature up to 750°C, which can be ascribed to the formation of well-crystallized metal oxides during calcination. Under experimental conditions, 97.8% degradation efficiency of RhB and 98.9% degradation efficiency of paracetamol were achieved after 240min. Active species trapping and EPR experiments suggested that hole (h(+)), superoxide radical (O2(-)) and hydroxyl radical (OH) played important roles during the RhB photocatalytic process. Moreover, the results indicated that the synthesized Zn-Al-Ce-MMO materials had good stability and reusability.

Keywords: Cerium; Doping; Layered double hydroxide; Multi-metal oxides; Photocatalysis.