A stable dye-sensitized photoelectrosynthesis cell mediated by a NiO overlayer for water oxidation

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 117; no. 23; pp. 12564 - 12571
• Main Authors: Wang, Degao, Niu, Fujun, Mortelliti, Michael J., Sheridan, Matthew V., Sherman, Benjamin D., Zhu, Yong, McBride, James R., Dempsey, Jillian L., Shen, Shaohua, Dares, Christopher J., Li, Fei, Meyer, Thomas J.
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 09.06.2020
• Subjects: Absorbers; Arthur M. Sackler on the Status and Challenges in Decarbonizing our Energy Landscape; artificial photosynthesis; Carbon dioxide; Catalysis; catalysis (heterogeneous); catalysis (homogeneous); Catalysts; charge transport; COLLOQUIUM PAPERS; core/shell; defects; electrocatalysis; Electrodes; Electron transfer; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; materials and chemistry by design; mediator; mesostructured materials; Nanoparticles; Nickel oxides; NiO; Oxidation; Performance enhancement; Photoelectric effect; Photoelectric emission; Photoelectrochemical devices; photosynthesis (natural and artificial); Photosystem II; Physical Sciences; solar (fuels); synthesis (novel materials); synthesis (self-assembly); Tin dioxide; Titanium dioxide; water oxidation; Water splitting; artificial photosynthesis; water oxidation; mediator; NiO; core/shell
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1821687116

In the development of photoelectrochemical cells for water splitting or CO₂ reduction, a major challenge is O₂ evolution at photoelectrodes that, in behavior, mimic photosystem II. At an appropriate semiconductor electrode, a water oxidation catalyst must be integrated with a visible light absorber in a stable half-cell configuration. Here, we describe an electrode consisting of a light absorber, an intermediate electron donor layer, and a water oxidation catalyst for sustained light driven water oxidation catalysis. In assembling the electrode on nanoparticle SnO₂/TiO₂ electrodes, a Ru(II) polypyridyl complex was used as the light absorber, NiO was deposited as an overlayer, and a Ru(II) 2,2′-bipyridine-6,6′-dicarboxylate complex as the water oxidation catalyst. In the final electrode, addition of the NiO overlayer enhanced performance toward water oxidation with the final electrode operating with a 1.1 mA/cm² photocurrent density for 2 h without decomposition under one sun illumination in a pH 4.65 solution. We attribute the enhanced performance to the role of NiO as an electron transfer mediator between the light absorber and the catalyst.