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The application of naturally abundant resources as alternative raw materials has been intensively studied because it is more economical and is also able to reduce solid waste generated by various industries. In this study, SiO2 was successfully extracted from sugarcane bagasse ash and pumice stone by using a low-temperature alkaline extraction method and acid precipitation process with high purity levels (98.4% and 96.3%, respectively). The extracted SiO2 was used as a catalyst support for Ag2O, where the two components were integrated with the impregnation method. The resulting catalysts were characterized to understand their structural features, as well as to see the catalytic performance. All samples of catalysts succeeded to reduce 4-nitrophenol, with differences in their reaction rates. The sample of Ag2O/SiO2, in which SiO2 was extracted from pumice stone, shows higher catalytic activity than that of sugarcane bagasse ash. From the analysis in this study, it is found that the aforementioned phenomenon is closely related to the structural properties of both Ag2O and SiO2 as the catalyst and its support.

The influence on sulphur content in term of thiourea (TU) concentration on the properties of nickel sulphide (NiS)-reduced graphene oxide (rGO) has been reported in this paper. The effect of sulphur content on the performance of dye-sensitized solar cell (DSSC) using NiS-rGO counter electrode (CE) has also been investigated. The source of sulphur is TU. The sample has been prepared via modified Hummers’s method assisted with spin coating technique. The cell using NiS-rGO CE prepared with 1.20 M TU yielded the highest power conversion efficiency (η) of 1.42%. This is due to this cell has the lowest series resistance (Rb) and charge transfer resistance at the interface of NiS-rGO CE/electrolyte (Rct) with the value of 0.44 and 4.09 Ω, respectively. It is also due to the sample with 1.20 M TU owns the highest reduction current (J). The finding of this work reveals that NiS-rGO is able to substitute platinum as CE for DSSC.

In this research paper, we are basically interested in the theoretical investigation of magnetic and magnetocaloric properties of CoFeCuO4 spinel ferrite. Our sample was prepared using the sol-gel method. The XRD analysis confirmed the cubic spinel structure with the Fd (3) over barm space group exhibited by our compound. Furthermore, the positive slope detected in the Arrott plots is indicative of the second-order phase transition. Based on the phenomenological model of Hamad, the simulation of the magnetization M (T) goes in good agreement with the experimental results. Moreover, the magnetic entropy change (-Delta S-M) estimations by Hamad's model and Landau theory go in good accordance with the experimental results determined using Maxwell relations above the Curie-temperature T-C, and they show a divergence below this temperature. The relative cooling power (RCP) has a value of 64.342 J.kg(-1) under a magnetic field of 5T, which is suggestive that our compound can be a promising material for the magnetic refrigeration (MR) application. Finally, the validity of the mean-field theory to the theoretical study was proven through the compatibility inferred between the (-Delta S-M(max)) and RCP values obtained by the Maxwell relation and the Bean-Rodbell model. info:eu-repo/semantics/publishedVersion

Dye-Sensitized Solar Cells (DSSCs) or Gratzel cells have attracted widespread attention due to their low cost, ease of fabrication, and reasonably good photochemical conversion efficiency. The photochemical efficiency of solar cells mainly depends on their design, development, electrodes, and electrolyte used. The use of conducting polymers in solar cells helps in reducing the cost of DSSCs with the same efficiency. Polyaniline acts as a promising conductive polymer mainly used as a counter electrode catalyst on FTO glass as well as on flexible substrates. It allows large-scale mass production and significant cost savings in the manufacturing of solar cells. This paper reviews the feasibility of Polyaniline and its composites as a counter-electrode catalyst for DSSCs. Its application as hole conductors, a catalyst for photosensitized electrolytes. The mechanism of its photocatalytic activities is well explained. The Polyaniline and Polyaniline based solar cells shows the efficiency from 7.1 to 12% with different dyes and electrolyte solutions. The recent advances made with this polymer, a suitable replacement for platinum, is also intensely reviewed.

A novel mixed-anion phosphate, KMg6(P2O7)2P3O10, has been synthesized by spontaneous crystallization technique with K2O–P2O5–Li2O as a flux. Single-crystal X-ray analysis reveals that KMg6(P2O7)2P3O10 features two kinds of isolated anions, [P2O7] dimers and [P3O10] trimers. Such coexisting of two distinct anions in one polyphosphate, which has somewhat conflict with Pauling's parsimony (V) rule, is very rare in alkali metal and alkali-earth metal phosphates. This finding enriches the structural chemistry of phosphates and provides new perspective on the design of multiple anion materials. The thermal stability and a.c. conductivity of KMg6(P2O7)2P3O10 are also discussed in this paper.

Made available in DSpace on 2018-12-11T16:59:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-01-01 The sulfide anion is a corrosive, toxic and harmful compound found in a wide range of anoxic environments. Metal-based complexes have been used as luminescent probes for sulfide determination. However, their synthesis usually involves laborious procedures and the use of toxic reagents. In this paper, we describe the synthesis, characterization and application of a new, sensitive and selective silver complex probe for sulfide detection. The process of sulfide determination is based on rapid reaction in aqueous/methanolic media between the silver (I) complex and sulfide leading to an increase in fluorescence intensity. Analytical performance has been studied in the concentration range of 190 to 950 nmol L- 1 of sulfide with suitable linearity, and the limit of detection was calculated to be (3σ/S) to 20 nmol L- 1. The probe's selectivity to S2 - was evaluated over other competing anions showing excellent results and its reversibility was demonstrated upon addition of AgCF3SO3. Depto de Química Geral e Inorganica Instituto de Química UNESP, Rua Francisco Degni 55 School of Chemistry University of Nottingham Depto de Química Geral e Inorganica Instituto de Química UNESP, Rua Francisco Degni 55