To rigorously exclude the role of the polypyridyl iron complex (1) in water oxidation, we functionalized FTO electrodes with MA2 without this electrochromic component. A solution of PdCl2(PhCN)2 (4.0 mM, THF) and the vinylpyridyl ligand L (2.0 mM, DCM:MeOH = 1:1 v/v) were spin-coated on FTO/glass (2 cm × 2 cm) using fully automated spin-coating (see the supporting information for details and Figure ). This deposition sequence was repeated 15 times. UV-Vis spectroscopy shows a linear growth process, which was validated by plotting the absorption intensity at λmax = 333 nm versus the number of deposition cycles (Figure ). CV measurements recorded under the same conditions as for MA1 did not show the oxidation and reduction peaks that were attributed to complex 1 (Figure ). The observed onset potentials and catalytic currents are similar to the values observed with MA1. The Tafel slope of 217 mV/dec and the current density from CPE at a constant applied potential of 1.75 V vs Ag/Ag + for 7 h are also similar (Figure ). Bubbles are clearly observable at the working and counter electrodes. GC analysis of the gas mixture revealed that 896 μmol of H2 was produced (≈ 448 μmol of O2) after 6.5 h. CPE indicated that 264 C of charge passed for an active surface area of 2.4 cm 2 , corresponding to a Faradaic efficiency (FE) of 67% (see the supporting information for details). An anodization process similar to the one observed for MA1 was observed here as well (Figure ). These observations confirm that the role of complex 1 is limited to electrochromism, and indicate that the palladium component catalyzes the water splitting for both MAs.