Co3O4 Nanopetals on Si as Photoanodes for the Oxidation of Organics

Abstract

Cobalt oxide nanopetals were grown on silicon electrodes by heat-treating metallic cobalt films deposited by DC magnetron sputtering. We show that cobalt oxide, with this peculiar nanostructure, is active towards the photo-electrochemical oxidation of water as well as of organic molecules, and that its electrochemical properties are directly linked to the structure of its surface. The formation of Co3O4 nanopetals, induced by oxidizing annealing at 300 °C, considerably improves the performance of the material with respect to simple cobalt oxide films. Photocurrent measurements and electrochemical impedance are used to explain the behavior of the different structures and to highlight their potential application in water remediation technologies.

Diffusion-driven formation of Co3O4 nanopetals layers for photoelectrochemical degradation of organophosphate pesticides

“…A lower thickness of this layer obviously corresponds to a lower optical absorbance (especially in the spectral range above the Co 3 O 4 energy gap, i.e. E g = 1.54 eV [37]) and this is useful in the case where shining the substrate is of interest, as for example when Co nanopetals have to be coupled to Si photoanodes [21,23].…”

“…Co 3 O 4 in form of nanostructured thin films has been widely investigated [13], with recent works dealing with applications as supercapacitors [14] and sensors [15,16,17,18] as well as with its superior catalytic and photocatalytic performances [19,20], coupled to a protective action towards Si photoanodes for water splitting applications [21,22]. Co 3 O 4 films decorated with nanopetals and nanowalls combine a wide surface area with a robust structure, interesting for photoelectrocatalytic applications in oxygen evolution reactions or photoelectrochemical sensing [23,21]. The formation of a nanopetal layer can be obtained by oxidation of a metallic Co foil or film in the temperature range 300-450 • C [24,25,26,27].…”

Work Function Tuning in Hydrothermally Synthesized Vanadium-Doped MoO3 and Co3O4 Mesostructures for Energy Conversion Devices

“…Focusing on the semiconducting materials, there is flourishing research in the optimization of electronic properties of metal oxides in order to fulfill the stringent requirements of next generation clean energy conversion devices such as solar cells [10]. This is the case, for example, of MoO 3 and Co 3 O 4 , that show different electrical properties [11][12][13][14][15] but present one issue: the low mobility of charge carriers. In fact, both oxides are used in photovoltaics for different reasons.…”

Синтез гетерогенных наноструктур ZnO/Co-=SUB=-3-=/SUB=-O-=SUB=-4-=/SUB=- методом химического осаждения из растворов

“…Оксид кобальта Co 3 O 4 является полупроводником ртипа проводимости, этот материал весьма перспективен для использования в широком круге практических приложений, таких, как электрохимическое расщепление воды и получение водорода [1], электрохимические сенсоры и фотокаталитическое окисление органических загрязнений в воде [2], анодные материалы для литийионных батарей [3]. Благодаря тому, что на поверхности Co 3 O 4 может осуществляться широкий спектр обратимых окислительно-восстановительных реакций, оксид кобальта используется в электродах для ассиметричных суперконденсаторов [4].…”