title: Photoelectrolysis of water: Solar hydrogen--achievements and perspectives.
abstract: Thermodynamic analysis of energy conversion from light-to-chemical, light-to-electric and electric-to-chemical is presented by the case study of water photoelectrolysis on TiO(2) surface. It is demonstrated that at the current state-of-the-art energy conversion efficiency of water photoelectrolysis can be increased approximately 17 times by separating the processes of solar-to-electric and electric-to-chemical energy conversion and optimizing them independently. This allows to mitigate a high overvoltage of oxygen evolution reaction with respect to thermodynamic E(0)(O(2)/H(2)O) = 1.23 V potential as well as spectrally narrow absorbtivity of solar light by TiO(2) which determine the low efficiency (approximately 1.0%) of direct light-to-chemical energy conversion. Numerical estimates are provided illustrating practical principles for optimization of the solar energy conversion and storage processes.
authors.affiliation: Institute of Chemistry, A. Gostauto 9, Vilnius 01108, Lithuania. kesjuod@ktl.mii.lt
authors.forename: Kestutis
authors.initials: K
authors.lastname: Juodkazis
authors.forename: Jurga
authors.initials: J
authors.lastname: Juodkazyte
authors.forename: Edgaras
authors.initials: E
authors.lastname: Jelmakas
authors.forename: Putinas
authors.initials: P
authors.lastname: Kalinauskas
authors.forename: Ignas
authors.initials: I
authors.lastname: Valsiūnas
authors.forename: Povilas
authors.initials: P
authors.lastname: Mecinskas
authors.forename: Saulius
authors.initials: S
authors.lastname: Juodkazis