functions 37 and for the MIL-53(Fe) solid functionalized by a variety of polar/unpolar groups. 38 ■ ASSOCIATED CONTENT * S Supporting Information Details of force field, soft mode analysis, and a video illustrating the breathing effect of MIL-53(Cr) material. This material is available free of charge via the Internet at http://pubs.acs.org.

The correlation between ex situ electronic conductivity, oxygen vacancy content, flat-band potential (Efb), and the oxygen evolution reaction (OER) activity for a wide range of perovskite compositions [La1-xSrxCoO3−δ series (with x = 0, 0.2, 0.4, 0.6, 0.8), LaMO3−δ series (M = Cr, Mn, Fe, Co, Ni), Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF), and PrBaCo2O6−δ (PBCO)] are investigated experimentally and theoretically. It is found that all of these parameters can affect the OER activity; however, none of them alone play a crucial role in determining the electrocatalytic activity. The correlation of one single physicochemical property with the OER activity always presents deviation points, indicating that a limitation does exist for such 2-dimensional correlations. Nevertheless, these deviations can be explained considering other physicochemical properties and their correlation with the OER activity. Hence, this work aims in simultaneously linking the OER activity with several physicochemical materials properties. The concept of the OER/multidescriptor relationship represents a significant advancement in the search and design of highly active oxygen evolution catalysts, in the quest for efficient anodes in water electrolyzers.

A method to control the arrangement of various metal elements in MOFs at atomic and mesoscopic scales is described.