Figure 1.

Catalytic and electrical properties of Ni_0.8Fe_0.2O_x. (a) SEM image of a conformal and crack-free Ni_0.8Fe_0.2O_x film on an ITO substrate. (b) CV scan and in situ measurement of conductivity (at steady-state, held at each point for 3 min) of Ni_0.8Fe_0.2O_x film on ITO. (c) In situ recording of V_WE2 versus V_ITO (controlled by WE1 in chronoamperometry steps). The drift of V_WE2 when the electrocatalyst is insulating is due likely to the slow equilibration between the Au layer and poorly defined solution/catalyst-film species. The voltages V_WE2 and V_ITO are both reported relative to the thermodynamic redox potential for the OER.