Retraction notice to “Stable and sustainable photoanodes using zinc oxide and cobalt oxide chemically gradient nanostructures for water-splitting applications” [Journal of Colloid And Interface Science 558 (2020) 9–20, (S0021979719311294), (10.1016/j.jcis.2019.09.086)]

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of Editor-in-Chief and Handling Editor. Several instances of potential image manipulation in the manuscript have been detected, and specifically: Figure 1 contains potential duplications, detectable by total or partial overlap of the SEM Image (part a) and graph (part c). Figure 2 contains potential duplications, detectable by total or partial overlap of the SEM Images. Figure 7(c) contains potential duplications, detectable by total or partial overlap of the XPS data (including the noise) by potential manipulating and shifting the data's x-axis for each set of data (before and after electrochemical experiments). Figure S2 contains potential duplications, detectable by total or partial overlap of the SEM (Scanning Electron Microscopy) images. Moreover, the Proofig AI platform identified a total of 9 subimages with suspected duplication or alteration issues in file (matchings in the range 62-309 features). The multiple and systematic occurrence of potential image duplication and manipulation undermines the credibility and reliability of the experimental data presented in the manuscript, as well as the validity of the conclusions drawn from it. Apologies are offered to readers of the journal.