Influence of organic additives on the initial stages of copper electrodeposition on polycrystalline platinum

Synchronous reduction-fixation of reducible heavy metals from aqueous solutions: Application of novel mesoporous MFT/SBA-15 composite materials

The usual treatment for Cr(VI)-contaminated wastewater primarily included reduction, adsorption, and the subsequent separation of the Cr-laden adsorbent. Among these factors, the adsorbent is the most critical factor in determining Cr removal efficiency. In this study, a novel melamine-formaldehyde-thiourea (MFT) chelating resin/mesoporous silica composite material (MFT/SBA-15) was synthesized via a co-condensation method and used for the reduction and fixation of Cr(VI)-contaminated water. Cr(VI) adsorption onto MFT/SBA-15 obeyed the pseudo-second-order model, and the chemical adsorption was the rate-limiting step in the adsorption process. Also it followed the Langmuir adsorption model, with single molecular layer adsorption characteristics. The organic components within MFT/SBA-15 were the core functional groups for Cr(VI) adsorption, and the formation of a coordination bond (CS→Cr) between the lone electron pairs of the S atom and Cr during the adsorption process led to the synchronous reduction-fixation processes of Cr(VI). These synchronous effects were further demonstrated for other reducible heavy metals, including As(V) and Cu(II), but negligibly observed in chemically stable elements, such as Zn(II), Ni(II), Pb(II), Cd(II), and As(III). The novel mesoporous MFT/SBA-15 materials combine the advantages of the chelating resin and mesoporous silica and have excellent potential for the wastewater treatment of reducible heavy metals through synchronous reduction-fixation.

Cu–MoS2 Superhydrophobic Coating by Composite Electrodeposition

In this work, a superhydrophobic coating was developed by composite electrodeposition of MoS2 particles in a copper matrix. AISI 316L stainless steel and N80 carbon steel, with a thin electrodeposited Ni layer to improve adherence of the coating, were used as substrates. Different operational parameters of electrodeposition were studied in order to produce the highest possible contact angle. We demonstrate that, using this method, a coating with a hierarchical structure with feature dimensions in the range of µm to nm is obtained, with advancing contact angle values up to 158.2° and a contact angle hysteresis equal to 1.8°. To study the coating composition energy dispersive X-ray, X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry were performed. Moreover, potentiodynamic polarizations were performed in H2SO4, NaCl and NaOH solutions to study the corrosion behavior of the coating. As a control, a sample coated only with MoS2 particles by means of electrophoretic deposition was produced. The results show that the composite coating can be used in applications where copper is used for corrosion protection, with the addition of the desirable effects of its superhydrophobicity.

Electrodeposition of nanowires of a high copper content thiourea precursor of copper sulfide

Copper thiourea complexes are an important material class for application as a precursor of copper sulfide nanocrystals with potential use in solar cells, optoelectronics, medicine, etc. They represent a type of single source precursor, comprising both copper and sulfur in one chemical compound, whose tunable stoichiometry and morphology enable control of the quality and properties of the synthesized copper sulfide nanocrystals. Here, we present a template free electrochemical route to prepare nanowires of copper thiourea (tu) chloride hemihydrate ([Cu(tu)]Cl·½H₂O) by pulse deposition. We proposed the model of the growth of nanowires. We also demonstrate complete transformation from the precursor to copper sulfide nanowire by heating it to 180 °C that involves 20% volume loss due to the decomposition of organic constituents; the obtained nanowires have around 38% covellite (CuS) and 62% digenite (Cu_1.8S) phases. Electrochemistry offers the advantage of spatially selected deposition e.g. in the active regions of a device.

In this study we reported the pulsed electrodeposition technique of copper thiourea complex nanowires which is an important material class for application as a precursor of copper sulfide nanocrystals with potential use in solar cells, optoelectronics, medicine, etc.

Cross-linker mediated formation of sulfur-functionalized V2O5/graphene aerogels and their enhanced pseudocapacitive performance

The development of efficient synthesis methods for the preparation of vanadium oxide (V₂O₅)-graphene holds great promise considering the excellent performance of the composite in electrochemical applications. Herein, we report the cross-linking of a V₂O₅-graphene hybrid via a vanadium-thiourea redox system, which allowed the assembly of graphene oxide functional groups with V₂O₅ through the reducing ability of thiourea (TU) under room conditions within an impressively short reaction time (20 min). The resulting 3D composite aerogel forms a highly porous architecture of sulfur-functionalized interconnected networks. Such sulfur-functionalized transition metal oxide-graphene-based aerogels are excellent candidates in energy storage applications. When the vanadium oxide-graphene aerogel was evaluated as an electrode for a supercapacitor, a specific capacitance as high as 484.0 F g^-1 at 0.6 A g^-1 was obtained in a two-electrode cell configuration. This performance is much higher than that of the vanadium oxide-graphene aerogels prepared in the absence of thiourea. The vanadium oxide-graphene aerogel is able to deliver a remarkable energy density of 43.0 Wh kg^-1 at a power density of 0.48 kW kg^-1 at 0.6 A g^-1 and can hold 24.2 Wh kg^-1 at a maximum power density of 9.3 kW kg^-1 at 10 A g^-1. The symmetric supercapacitor assembled from the aerogel can retain 80% of its initial capacitance after 10 000 cycles.