Metal Oxides and Hydroxides as Rechargeable Materials for Photocatalysts with Oxidative Energy Storage Abilities

Abstract

NiO, Co(OH) 2 , Ir oxide, and Ru oxide were combined as rechargeable materials with TiO 2 or Pt-TiO 2 photocatalyst to obtain novel photocatalysts with oxidative energy storage abilities. NiO, which is more stable than the conventional storage material, Ni(OH) 2 , showed similar characteristics to those of Ni(OH) 2 . The redox potential of Co(OH) 2 was more negative, and those of Ir oxide and Ru oxide were more positive than that of Ni(OH) 2 . The photoelectrochemically charged Ir oxide was reduced by acetone, acetic acid, Br − , and water. The diversity of energy storage materials was accordingly improved in terms of the reaction potential and stability.

Materials and Mechanisms of Photo‐Assisted Chemical Reactions under Light and Dark Conditions: Can Day–Night Photocatalysis Be Achieved?

“…Apart from application-oriented studies, conventional systems, such as TiO 2 ÀWO 3 , [75][76][77][78][79][80] and TiO 2 ÀNi(OH) 2 , [81][82][83][84][85] have been exclusively studied for their photocharging and discharging mechanisms, which could be potentially useful for the development of day-night-based photocatalytic systems. It is known that photocatalysis is being widely employed for pollutant degradation,w ater splitting, and fuel conversion applications.…”

NSAIDs as a Drug Repurposing Strategy for Biofilm Control

“…Moreover, most of these drugs are in early stages of development (phase I or II). In addition, the development of new drugs requires large monetary resources and is a very time-consuming process, with a high risk of failing in one of the testing phases [ 18 , 19 ]. Park [ 20 ] foresees a total development time of 13–15 years and a cost between USD 2 and 3 billion.…”

Metal and Metal Oxide Nanoparticles for Photoelectrochemical Materials and Devices

“…31 As an energy storage material, other redox-active p-type semiconductors, such as NiO and Co(OH) 2 , are also available. 6 Oxidative reactions can be driven at more positive potentials when Ir or Ru oxide is used as a rechargeable material. 6 Although TiO 2 photocatalyst does not function after dark and it is excited only by UV light, these two major limitations can be removed simultaneously by combining a rechargeable material with a visible light-driven photocatalyst, 4,5,8 such as Pt nanoparticle-loaded WO 3 developed by Ohtani et al, 32 Cu-loaded WO 3 33 or Fe-loaded TiO 2 34 developed by Hashimoto et al, or Au nanoparticle (AuNP)-loaded TiO 2 .…”

“…In particular, efficient light harvesting is an important issue, because ambient photon flux density is low in general. With this in mind, we have developed the following three new classes of nanomaterials and photoelectrochemical devices based on the nanomaterials: (1) photocatalysts with energy storage abilities, [1][2][3][4][5][6][7][8] which can store energy derived from light and continue redox reactions even in the night, (2) plasmonic metal nanoparticle ensembles stabilized by metal oxide nanomasks and ultrathin metal oxide coatings, 9,10 as well as solid-state photovoltaic cells 11 and plasmon resonance sensors 9,10,12 based on the ensembles, and (3) organic [13][14][15][16][17][18] or organic-inorganic hybrid [19][20][21] photoelectrodes with optimally arranged plasmonic metal nanoantennas. The former one stores surplus energy during the day and uses it in the night, while the latter two trap photons efficiently taking advantage of the large absorption cross-section of plasmonic metal nanoparticles.…”