This work reports on the in-situ chemical synthesis and their properties of multilayer graphene (MLG) shells, made by unzipping single walled carbon nanotubes (SWCNTs), on the surface of Zinc oxide (ZnO) core nanoparticles (NPs). The stable oxygen bridge bonds between the ZnO core and the oxygen-related functional groups on the MLG shells facilitate the efficient photoinduced charge separation. This charge separation mechanism is confirmed experimentally using time-correlated single photon counting (TCSPC) measurements. The calculated average carrier lifetimes of the ZnO@MLG NPs are approximately 102 times faster than those for the bare ZnO NPs. The efficient electron transfer between the ZnO core and the MLG shell resulted in the significant improvement of the photocatalytic activity and the photoelectrochemical response. Simultaneously, the photocorrosion of ZnO was prevented by having the oxygen bridge bonds between the ZnO and MLG which suppressed the photo-generated holes oxidizing the surface oxygen atoms on ZnO, and in turn the holes are consumed by photocatalytic reaction. The 4.3 times enhanced photocurrent density at 0.2 V vs. Ag/AgCl (pH 6.9) and around 10 times higher rate constant value of photodegradation of rhodamine B were achieved by ZnO@MLG NPs in comparison with those of bare ZnO NPs.
Bibliographical noteFunding Information:
D. I. Son appreciates the financial support from the KIST Institution Program, the R&D Convergence Program of MSIP (Ministry of Science, ICT and Future Planning) and ISTK (Korea Research Council for Industrial Science and Technology) of Republic of Korea (Grant CAP-13-2-ETRI ). J. K. Kim and J. H. Park acknowledge the support by the NRF of Korea Grant funded by the Ministry of Science, ICT and Future Planning ( NRF-2013R1A2A1A09014038 , 2009-0083540 ).
© 2016 Elsevier Ltd.
All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)
- Electrical and Electronic Engineering