Solution-Processed Chalcogenide Photovoltaic Thin Films

Chalcogenides-based thin film solar cells are great competitors to beat high efficiencies as silicone solar cells. The chalcogenides that have been commonly used as absorber materials are CIS, CIGS, and CZTS. They present some advantages of having a direct and tunable band gap, high absorption coefficient and respectable efficiency to cost ratio. Solution processable deposition approaches for the fabrication of solar cells attracts a great deal attention due to its lower capital cost of the manufacturing than the vacuum-based techniques. In this chapter, we detail the use of a low-cost method of deposition for the chalcogenide thin films by spin-coating and spray-coating, which is already widely employed in several fields of industries

A New Indirect Electroanalytical Method to Monitor the Contamination of Natural Waters with 4-Nitrophenol Using Multiwall Carbon Nanotubes

The electrochemical detection of the hazardous pollutant 4-nitrophenol (4-NP) at low potentials, in order to avoid matrix interferences, is an important research challenge. This study describes the development, electrochemical characterization and utilization of a multiwall carbon nanotube (MWCNT) film electrode for the quantitative determination of 4-NP in natural water. Electrochemical impedence spectroscopy measurements showed that the modified surface exhibits a decrease of ca. 13 times in the charge transfer resistance when compared with a bare glassy carbon (GC) surface. Voltammetric experiments showed the possibility to oxidize a hydroxylamine layer (produced by the electrochemical reduction of 4-NP on the GC/MWNCT surface) in a potential region which is approximately 700 mV less positive than that needed to oxidize 4-NP, thus minimizing the interference of matrix components. The limit of detection for 4-NP obtained using square-wave voltammetry (0.12 mu mol L(-1)) was lower than the value advised by EPA. A natural water sample from a dam located in Sao Carlos (Brazil) was spiked with 4-NP and analyzed by the standard addition method using thee GC/MWCNT electrode, without any further purification step. the recovery procedure yielded a value of 96.5% for such sample, thus confirming the suitability of the developed method to determine 4-NP in natural water samples. The electrochemical determination was compared with that obtained by HPLC with UV-vis detection.CNPqConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP, Brazil[06/50692-2

Utilização de eletrodos sólidos de amálgama para a determinação analítica de compostos orgânicos e inorgânicos

This review reports the use of solid amalgam electrodes in the electroanalytical determination of organic and inorganic compounds. The different types of amalgam electrodes are presented, and attention is paid to solid amalgam electrode, and here is presented details about the pre-treatment for activation and renovation and also possible modifications in its surface. The wide potential range, higher signal-to-noise ratio, mechanical stability enabling their application in flowing systems, and principally their resistance toward passivation, indicate that the solid amalgam electrodes are environmentally friendly alternatives to mercury electrodes, without loss in the sensitivity and reproducibility in voltammetric responses

Glycerol electro-oxidation at Pt in alkaline media: influence of mass transport and cations

Glycerol is an important biomass-derived product with potential to be applied on energy converting systems or as platform molecule in electrosynthesis. In this work we studied the glycerol oxidation reaction (GOR) in alkaline media containing distinct alkaline cations and controlling the mass transport. The cyclic voltammograms were deconvoluted into three processes and the changes in the charge of each process revealed that mass transport affects the GOR in a complex matter, depending on both applied potential and electrolyte cation. Regardless of the cation on supporting electrolyte, high-performance liquid chromatography (HPLC) analysis revealed the production of glycerate and lactate during GOR. Finally, potential oscillations under current control were mapped, highlighting the influence of both cations and mass transport, even in the systems with very similar behavior under potential control.The authors thank to the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001 and the Conselho Nacional de Pesquisa e Desenvolvimento (CNPq), for fellowships and grants (#430426/2018-6). The authors also thank the São Paulo Research Foundation (FAPESP) (Grants #2013/07296-2, #2014/50249-8, #2017/11986-5, #2018/20952-0 and #2019/00305-2), Shell, and the strategic importance of the support given by ANP (Brazil's National Oil, Natural Gas and Biofuels Agency) through the R&D levy regulation

Perylenediimide-Incorporated Covalent Triazine Framework: A Highly Conductive Carbon Support for Copper Single-Atom Catalysts in Electrocatalytic CO2 Conversion

<p>This upload has been published in Energy & Fuels 2023 (10.1021/acs.energyfuels.3c03268).</p><p>Abstract: </p><p>Here, we show that a perylenediimide-incorporated covalent triazine framework (PDI-CTF) leads to adequate conductive carbon support for copper single-atom catalysts (Cu-SACs), allowing the selective CO2 electroreduction to methanol. CTF-Cu-SACs converted CO2 into methanol with a faradaic efficiency of 72.6% at a low overpotential (0.2 V vs. RHE). While increasing the overpotential (0.2 to -0.4 V vs. RHE), CTF-Cu-SACs promoted syngas (CO and H2) production with faradaic efficiencies of 53.2% and 39.5 %, respectively. Moreover, CTF-Cu-SACs led to robust catalytic stability for 20 h of continuous electrolysis in an aqueous solution. Notably, it was observed that additional nitrogen doping to the PDI-CTF profoundly influences product selectivity, possibly due to the synergetic effect of highly conductive pyrolyzed CTF and N-chelating ligands with rich active sites. Our results indicate that the PDI-CTF-based Cu-SACs provide abundant active sites for CO2 adsorption, thus enhancing intermolecular ion and charge transportation that efficiently reduces CO2 into methanol in an aqueous system. </p&gt