Reaction kinetics and interplay of two different surface states on hematite photoanodes for water oxidation.

Understanding the function of surface states on photoanodes is crucial for unraveling the underlying reaction mechanisms of water oxidation. For hematite photoanodes, only one type of surface states with higher oxidative energy (S1) has been proposed and verified as reaction intermediate, while the other surface state located at lower potentials (S2) was assigned to inactive or recombination sites. Through employing rate law analyses and systematical (photo)electrochemical characterizations, here we show that S2 is an active reaction intermediate for water oxidation as well.

Ir- and Ru-doped layered double hydroxides as affordable heterogeneous catalysts for electrochemical water oxidation.

Three M-doped LDHs (M = noble metal active site, LDH = layered double hydroxides; Ir-1, Ir-ZnAl; Ru, Ru-ZnAl; Ir-2, Ir-MgAl), containing small amounts of M (ca. 2 mol% and even <1 mol% for Ru and Ir, respectively), were prepared by following simple and established synthetic procedures. Their characterization indicates that M atoms are effectively incorporated into the brucite-like layers of LDH, without phase segregation.