Figure 5 Photo-driven water oxidation in butylammonium protic ILs Panel b adapted with permission from McDonnell-Worth, C. & MacFarlane, D. R. Ion effects in water oxidation to hydrogen peroxide. RSC Adv. 4, 30551–30557 (2014), The Royal Society of Chemistry. Panel d adapted with permission from Zhou, F. et al. Enhanced photo-electrochemical water oxidation on MnOx in buffered organic/ inorganic electrolytes. J. Mat. Chem. A 3, 16642–16652 (2015), The Royal Society of Chemistry MacFarlane, D. R. et al. (2016) Ionic liquids and their solid-state analogues as materials for energy generation and storage Nat. Rev. Mater doi:10.1038/natrevmats.2015.5