Amorphous carbon layer: An effective assistant for realizing near-infrared-activated photocatalysis

Yuanyuan Zhang; Lili Wang; Xiumei Ma; Manli Yang; Haiyan Jiang; Lin Li; Chuancong Yuan; Jinsheng Shi

doi:10.1016/j.jcis.2018.07.041

Amorphous carbon layer: An effective assistant for realizing near-infrared-activated photocatalysis

J Colloid Interface Sci. 2018 Dec 1:531:47-55. doi: 10.1016/j.jcis.2018.07.041. Epub 2018 Jul 17.

Authors

Yuanyuan Zhang¹, Lili Wang¹, Xiumei Ma², Manli Yang¹, Haiyan Jiang¹, Lin Li¹, Chuancong Yuan¹, Jinsheng Shi³

Affiliations

¹ Department of Chemistry and Pharmaceutical Science, Qingdao Agricultural University, PR China.
² Electron Microscopy Laboratory, School of Physics, Peking University, PR China.
³ Department of Chemistry and Pharmaceutical Science, Qingdao Agricultural University, PR China; Qingdao Bona Biomimetic Composite Research Institute Co. Ltd., PR China. Electronic address: jsshiqn@aliyun.com.

PMID: 30025327
DOI: 10.1016/j.jcis.2018.07.041

Abstract

Carbon quantum dots (CQDs) were considered as desirable up-conversion luminescent materials. However, the reason leading to their up-conversion luminescence was not clear. In this paper, CQDs decorated ZnSn(OH)₆ was successfully synthesized by facile in situ hydrothermal method. Under NIR light irradiation, ciprofloxacin degradation efficiency of sample was 37.4%. Subsequently, reasons for the up-conversion effect of CQDs were investigated to some extent. An amorphous carbon layer around CQDs was observed in composite (ZnSn(OH)₆@CQDs@C) by HR-TEM and elemental mapping images. To study the effect of amorphous carbon layer on up-conversion performance, individual CQDs decorated ZnSn(OH)₆ (ZnSn(OH)₆@CQDs) was also fabricated by compositely coating. ZnSn(OH)₆@CQDs had no up-conversion luminescence under 980 nm laser light excitation and its photocatalytic activity was negligible, implying amorphous carbon layer played a crucial role for realizing of up-conversion luminescence. A comparison of the FTIR spectra of two composites, ZnSn(OH)₆@CQDs@C sample revealed greatly enhanced surface oxidation degree, polarity and hydrophilicity. Surface state of ZnSn(OH)₆@CQDs@C composite was controlled by adjusting hydrothermal time, and the results confirmed that up-conversion performance had a close relationship with surface states of samples. This work could provide a new insight into understanding the up-conversion effect of CQDs.

Keywords: Amorphous carbon layer; CQDs; Near-infrared-activated photocatalysis; Up-conversion reason; ZnSn(OH)(6).