Retraction of: Scientific Reports https://doi.org/10.1038/s41598-017-11142-y, published online 06 September 2017


Editors have retracted this Article.


Concerns were raised that some of the data in this paper appears to have been previously published in1 where it is described as representing different samples. Specifically, data in Figure 2 in this Article appears to be the same as data for sample D3 in Figure 1 in1; data in Figure 4a in this Article appears identical to data in Figure 2a in1 with the exception of the C-C peaks which appear to have been removed; data in Figure 4b in this Article appears to be identical to data in Figure 7a in1 with the exception of being shifted by approximately 6 eV. The Authors are not able to provide the original data due to the time that has passed since publication. The Editors no longer have confidence in the data reported in this Article.


Qingnan Meng agrees with the retraction. Editors were not able to establish the current contact details for other Authors.