title: Hematite-Based Solar Water Splitting in Acidic Solutions: Functionalization by Mono- and Multilayers of Iridium Oxygen-Evolution Catalysts.
abstract: Solar water splitting in acidic solutions has important technological implications, but has not been demonstrated to date in a dual absorber photoelectrochemical cell. The lack of functionally stable water-oxidation catalysts (WOCs) in acids is a key reason for this slow development. The only WOCs that are stable at low pH are Ir-based systems, which are typically too expensive to be implemented broadly. It is now shown that this deficiency may be corrected by applying an ultra-thin monolayer of a molecular Ir WOC to hematite for solar water splitting in acidic solutions. The turn-on voltage is observed to shift cathodically by 250 mV upon the application of a monolayer of the molecular Ir WOC. When the molecular WOC is replaced by a heterogeneous multilayer derivative, stable solar water splitting for over 5 h is achieved with near-unity Faradaic efficiency.
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St., Chestnut Hill, MA 02467 (USA).
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: Department of Chemistry, Yale University, 225 Prospect Street, PO Box 208107, New Haven, CT 06520-8107 (USA).
authors.forename: Stafford W
authors.initials: SW
authors.lastname: Sheehan
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St., Chestnut Hill, MA 02467 (USA).
authors.forename: Da
authors.initials: D
authors.lastname: He
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St., Chestnut Hill, MA 02467 (USA).
authors.forename: Yumin
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St., Chestnut Hill, MA 02467 (USA).
authors.forename: Xiahui
authors.initials: X
authors.lastname: Yao
authors.affiliation: Department of Chemistry and Biochemistry, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609 (USA).
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Grimm
authors.affiliation: Department of Chemistry, Yale University, 225 Prospect Street, PO Box 208107, New Haven, CT 06520-8107 (USA). gary.brudvig@yale.edu.
authors.forename: Gary W
authors.initials: GW
authors.lastname: Brudvig
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St., Chestnut Hill, MA 02467 (USA). dunwei.wang@bc.edu.
authors.forename: Dunwei
authors.initials: D
authors.lastname: Wang
keywords: hematite; homogeneous catalysis; iridium; photoelectrochemistry; solar water splitting