Correction to: Nature Communications https://doi.org/10.1038/s41467-019-10303-z, published online 14 June 2019.

The original version of this Article contained an error in Fig. 4a, in which an extra label ‘H2’ was inadvertently added. This has been corrected in both the PDF and HTML versions of the Article.

The correct version is:

It replaces the incorrect version: