Dye-sensitized photoanode decorated with pyridine additives for efficient solar water oxidation

Splitting water into hydrogen and oxygen by dye-sensitized photoelectrochemical cell (DSPEC) is a promising approach to solar fuels production. In this study, series of pyridine derivatives as surface additives were modified on molecular chromophore oxidation catalyst co-loaded TiO2 photoanode, TiO2|RuP, 1 (RuP = Ru(4,4?-(PO3H2)2-2,2?-bipyridine)(2,2?-bipyridine)2, Ru(bda)(L)2, (bda 2,2?-bipyridine-6,6?-dicarboxylate, L 10-(pyridin-4-yloxy)decyl)phosphonic acid). The addition was found result in up 42% increase photocurrent. Under simulated sun-light irradiation, 1, P1 (P1 4-Hydroxypyridine) produced photocurrent density mA/cm2 at bias 0.4 V vs. NHE acetate buffer. Moreover, the observed photocurrents are correlated with electron-donating ability substituent groups ring. Transient absorption measurements electrochemical impedance spectroscopy revealed that surface-bound can effectively retard back-electron transfer from conduction band oxidized dye, which major process responsible for energy loss DSPECs.