Manganese oxides are a highly promising class of water-oxidation catalysts (WOCs), but the optimal MnOx formulation or polymorph is not clear from previous reports in the literature. A complication not limited to MnOx-based WOCs is that such catalysts are routinely evaluated by different methods, ranging from the use a chemical oxidant such as Ce4+, photoactive mediators such as [Ru(bpy)3]2+, or electrochemical techniques. Here, we report a systematic study of nine crystalline MnOx materials as WOCs and show that the identity of the "best" catalyst changes, depending on the oxidation method used to probe the catalytic activity.

J. Am. Chem. Soc., 2015, DOI: 10.1021/jacs.5b05093

http://pubs.acs.org/doi/pdf/10.1021/jacs.5b05093