Chemistry Department, United States Naval Academy, Annapolis, Maryland 21402, USA.
Published: September 2010
AI Article Synopsis
Article Abstract
The Ru(II) compounds [Ru(bpy)(2)(mcbH)](2+) and [Ru(bpy)(2)(dafo)](2+), bpy is 2,2'-bipyridine where mcbH is 3-(CO(2)H)-2,2'-bipyridine and dafo is 4,5-diazafluoren-9-one, were synthesized, characterized, and anchored to nanocrystalline mesoporous TiO(2) thin films for excited state and interfacial electron transfer studies. X-ray crystallographic studies of [Ru(bpy)(2)(mcbH)](PF(6))(Cl) revealed a long Ru-N distance to the unsubstituted pyridine ligand of mcbH. Reaction of [Ru(bpy)(2)(dafo)](2+) with TiO(2) thin films resulted in interfacial chemistry. The IR, (1)H NMR, UV-vis, and photoluminescence spectral data indicated a room-temperature ring-opening reaction of the dafo ligand of [Ru(bpy)(2)(dafo)](2+) that ultimately yielded a carboxylate group in the 3-position of bipyridine anchored to TiO(2). Comparative reactions of [Ru(bpy)(2)(mcbH)](2+) with TiO(2) were performed and support this conclusion. In regenerative photoelectrochemical solar cells with 0.5 M LiI/0.05 M I(2) in acetonitrile, photocurrent action spectra were observed for both sensitized materials. The incident photon-to-current efficiency (IPCE) was significantly lower for Ru(bpy)(2)(dafo)/TiO(2), behavior attributed to a lower excited-state injection yield.
The use of metal oxide catalysts to enhance plasma CO reduction has seen significant recent development towards processes to reduce greenhouse gas emissions and produce renewable chemical feedstocks. While plasma reactors are effective at producing the intended chemical transformations, the conditions can result in catalyst degradation. Atomic layer deposition (ALD) can be used to synthesize complex, hierarchically structured metal oxide plasma catalysts that, while active for plasma CO reduction, are potentially vulnerable to degradation due to their high surface area and nanoscopic thickness.
The rational design of photonic crystal photocatalysts has attracted significant interest in order to improve their light harvesting and photocatalytic performances. In this work, an advanced approach to enhance slow light propagation and visible light photocatalysis is demonstrated for the first time by integrating a planar defect into CoO-TiO inverse opals. Trilayer photonic crystal films were fabricated through the successive deposition of an inverse opal TiO underlayer, a thin titania interlayer, and a photonic top layer, whose visible light activation was implemented through surface modification with CoO nanoscale complexes.
One method for the colorimetric detection of hydrogen peroxide vapor is based on a titanium-hydrogen peroxide complex. A color changing material based on a titania hydroxypropyl cellulose thin film was initially developed. However, as this material dries, the sensitivity of the material is significantly reduced.
Nickel electrodeposition is a widely utilized method for creating thin films on various substrates with various desirable attributes. Recently, there has been a growing interest in developing nickel composite coatings that incorporate additional elements or particles into the nickel matrix to enhance their properties. These composite coatings offer superior corrosion resistance, hardness, tribological, and other functional benefits compared with pure nickel coatings.
Thin-film deposition using sustainable precursors is required for various next-generation green energy applications. Here we report two atomic/molecular layer deposition processes for appreciably stable and conformal Ti-organic thin films and TiO:organic superlattices with potential in battery, photocatalysis and thermoelectric applications. These processes are based on the safe and sustainable titanium isopropoxide as the titanium precursor.
