Correction to: Scientific Reports https://doi.org/10.1038/s41598-017-19082-3, published online 15 January 2018

In Figure 5, Co-ZnO was incorrectly given as Ni-ZnO. In addition, the line on the graph for PVDF-HFP was omitted.

The correct Figure 5 appears below as Figure 1.

Figure 1
figure 1

.