Sol-gel Synthesis, Photo- and Electrocatalytic Properties of Mesoporous TiO2 Modified with Transition Metal Ions

Abstract

Mesoporous nanosized titania films modified with Co2+, Ni2+, Mn3+, and Cu2+ ions have been produced by templated sol-gel method and characterized by optical spectroscopy, X-ray diffraction (XRD), and Brunauer, Emmett, and Teller (BET) surface area measurement. Band gap energy and the position of flat band potentials were estimated by photoelectrochemical measurements. The films doped with transition metals possessed higher photocurrent quantum yield, as well as photo- and electrochemical activity compared to undoped samples. Mn+/TiO2 (M–Co, Ni, Mn, Cu) electrodes with low dopant content demonstrate high efficiency in electrocatalytic reduction of dissolved oxygen. Polarization curves of TiO2, TiO2/Ni2+, TiO2/Co2+/3+, and TiO2/Mn3+ electrodes contain only one current wave (oxygen reduction current). It means that reaction proceeds without the formation of an intermediate product H2O2.

Enhancing Lithium and Sodium Storage Properties of TiO2(B) Nanobelts by Doping with Nickel and Zinc

“…Furthermore, the spectrum of the TO-Ni-05 sample showed an absorption peak with a maximum at approximately 725 nm, the intensity of which strongly depended on nickel concentration (Figure S5, Supplementary Materials). This peak has previously been reported in the literature and was attributed to Ni 2+ ions in the octahedral coordination [48]. With regard to Zn-doped TiO2(B), its absorption edge also moved slightly toward longer wavelengths (i.e., red-shifted) as compared to the undoped sample.…”

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“…3, образцы № 1 -№ 5) определены их фотоэлектрохимические характеристики: потенциал плоских зон (Е пз ) и ширина запрещенной зоны (Е g ) для непрямых фотопереходов в запрещенной зоне TiO 2 . Значение потенциала плоских зон Е пз определяли из зависимостей фототока (І ф ) от потенциала Е. Значение Е пз позволяет оценить изменение положения дна зоны проводимости и энергию электронов, при участии которых протекают процессы восстановления, в том числе процесс электровосстановления кислорода [44]. Для определения ширины запрещенной зоны Е g спектральные зависимости квантового выхода фотоэлектрохимического тока перестраивались в координатах (hν×η) 0,5 ~ hν для непрямых разрешенных переходов в TiO 2 , где ηквантовый выход; hνэнергия кванта света.…”

Construction of Bio-TiO2/Algae Complex and Synergetic Mechanism of the Acceleration of Phenol Biodegradation

“…Titanium oxide (TiO 2 ) was the most promising photocatalyst because of its environmental friendliness, low cost, and stable properties. Studies have been reported to improve the performance of TiO 2 by combining it with other materials, such as doping cations (rare earth and transition metals) [ 26 , 27 ] or anions (halogen, sulfur, carbon, and nitrogen) [ 28 ], since high photoelectron-hole pair recombination rate reduced the efficiency of TiO 2 . Studies about TiO 2 with chlorophyll have been reported to broaden TiO 2 absorbance wavelength to visible light and reduce photoelectron-hole pair recombination rate [ 29 , 30 ].…”