Chromium doped copper vanadate photoanodes for water splitting

Solar hydrogen obtained from photoelectrochemical water splitting offers a versatile approach towards the substitution of fossil fuels by decentralized and sustainable resources, like water and sun. In the present study we have investigated the Chromium doped Copper Vanadate (Cr:Cu3V2O8) as a candidate photoanode for photoelectrochemical water splitting. We have synthetized this material through a simple aqueous precipitation reaction, which easily allows compositional modifications. We have studied the effect of extrinsic doping with substitutional atoms like Chromium on the optical and photoelectrochemical properties. The main limiting factor for performance is related to the high bulk recombination, which is partially overcome by 0.75 at.% Chromium doping, with a five-fold enhancement of the charge separation efficiency at 1.23 V vs RHE. Despite this remarkable milestone, significant further improvement is needed for the technological exploitation of this material

A simple approach to understand solid state chemistry with the example of a piezoelectric material incorporated in a birthday card

EDULEARN17 Proceedings: 9th International Conference on Education and New Learning Technologies Dates (3-5 July, 2017, Barcelona, Spain),Advanced solid materials are present in a large quantity of fields of our quotidian live. All the electronic devices surrounding us, such as mobile phones, computers or appliances are made up of many different materials: ceramics, metals, polymers, etc. The recent development of advanced ceramic materials to be applied in electronic devices, which require high performances as well as relatively economic syntheses and environmentally friendly characteristics, is a wide field in Materials Chemistry. It is important to motivate students to this area, so that, they can understand the importance of the chemistry and the material science in our society. In the present contribution, we would like to relate our experience giving a comprehensive laboratory session intended for all undergraduate chemistry students. Piezoelectric compounds can be defined as materials that produce some electric charge when a mechanical stress is applied (direct effect) or suffer a mechanical deformation when an electric field is applied (reverse effect). These materials are used in several devices such as lighters, speakers, sensors or sonars. Lead zirconate titanate [Pb(Ti 1-x ,Zr x )O 3 ] (PZT) is the most studied and commercialized ceramic piezoelectric mat erial due to their excellent characteristics. Relation between structure -composition -properties of this material and its easy preparation makes it suitable to use in low value added devices. In this work, we propose an example to understanding this technology based on the components of a speaker of a musical birthday card, in particular the piezoelectric component, including the chemistry that is involved in these types of devices. Two common characterization techniques in Solid State Chemistry are also int roduced to the students: X -Ray Diffraction and Electron Microscopy. Moreover, the discovery by the students of the presence of this type of material in this simple device offers a possibility to motivate them to learn these sciences, and allow them to know the importance of the Solid State Chemistry and the Materials Science in our society. Different educational methodologies may be used to study and understand these materials with piezoelectric properties. Problem Based Learning (PBL) is a widely applied approach intended to encourage students to learn through the structured exploration of a research problem. Currently this particular system has become a valid teaching method in high schools, where students are encouraged to develop a real research project. The PBL methodology used in this work represents an improvement in the content of the knowledge while simultaneously it fosters the development of communication, problem -solving, and self -directed learning skills. This work can also be interesting for tea chers of inorganic chemistry and material science and undergraduate students owing to its pedagogical character

Chromium doped copper vanadate photoanodes for water splitting

Solar hydrogen obtained from photoelectrochemical water splitting offers a versatile approach towards the substitution of fossil fuels by decentralized and sustainable resources, like water and sun. In the present study we have investigated the Chromium doped Copper Vanadate (Cr:Cu3V2O8) as a candidate photoanode for photoelectrochemical water splitting. We have synthetized this material through a simple aqueous precipitation reaction, which easily allows compositional modifications. We have studied the effect of extrinsic doping with substitutional atoms like Chromium on the optical and photoelectrochemical properties. The main limiting factor for performance is related to the high bulk recombination, which is partially overcome by 0.75 at.% Chromium doping, with a five-fold enhancement of the charge separation efficiency at 1.23 V vs RHE. Despite this remarkable milestone, significant further improvement is needed for the technological exploitation of this material

Dissociative electron attachment to gold(i) based compounds: 4,5-dichloro 1,3-diethyl imidazolylidene trifluoromethyl gold(i)

With the use of proton-NMR and powder XRD (XRPD) studies, the suitability of specific Au FEBID precursors has been investigated to low electron energy, structure, excited states and resonances, structural crystal modifications, flexibility, and vaporization level. Uniquely designed precursor to meet the needs of focused electron beam induced deposition (FEBID) at the nanostructure level, the 4,5-dichloro 1,3-diethyl imidazolylidene trifluoromethyl gold(i) is a compound that proves its capability to create high purity structures, and its growing importance between other AuImx and AuClnB (where x, n are the number of radicals, B = CH, CH3 or Br) compounds in the radiation cancer therapy increases the efforts to design more suitable bonds in processes of SEM deposition and in gas-phase studies. The investigation done to its powder shape using the XRPD XPERT3 Panalytical diffractometer based on CoK{\alpha} lines show changes to its structure with temperature, level of vacuum, and light; the sensitivity of this compound makes it highly interesting to radiation research in particular. Used for FEBID, through its smaller number of C, H, and O atoms has lower levels of C contamination in the structures and on the surface, but it replaces these bonds with C-Cl and C-N bonds that have a lower bond breaking energy but still needing an extra purification step in the deposition process, whether is H2O, O2 or H jets.Comment: 27 pages, 15 figure

Dissociative electron attachment to gold(i) based compounds: 4,5-dichloro – 1,3-diethyl – imidazolylidene trifluoromethyl gold(i)

With the use of proton-NMR and powder XRD (XRPD) studies, the suitability of specific Au FEBID precursors has been investigated to low electron energy, structure, excited states, resonances, structural crystal modifications, flexibility, and vaporization level. Uniquely designed precursor to meet the needs of focused electron beam induced deposition (FEBID) at the nanostructure level, the 4,5-dichloro – 1,3-diethyl – imidazolylidene trifluoromethyl gold(i) is a compound that proves its capability to create high purity structures, and its growing importance between other AuImx and AuClnB (where x, n are the number of radicals, B = CH, CH3 or Br) compounds in the radiation cancer therapy increases the efforts to design more suitable bonds in processes of SEM deposition and in gas-phase studies. The investigation done to its powder shape using the XRPD XPERT3 Panalytical diffractometer based on CoKα lines shows changes to its structure with temperature, level of vacuum, and light; the sensitivity of this compound makes it highly interesting to radiation research in particular. Used for FEBID, through its smaller number of C, H, and O atoms has lower levels of C contamination in the structures and on the surface, but it replaces these bonds with C – Cl and C – N bonds that have a lower bond breaking energy but still needing an extra purification step in the deposition process, whether is H2O, O2 or H jets