Hydroxy-Carboxylic Acids as Green and Abundant Ligands for Sustainable Recovery of Copper from a Multimetallic Powder: A Proof of Concept.

The recovery of copper and other valuable metals had become increasingly strategic for the future of the global economy, particularly in regions lacking abundant mineral resources, such as most European countries. In this study, we investigated the viability of utilizing environmentally friendly, cost-effective, abundant and bio-based ligands, specifically carboxylic acids and their derivatives, for copper leaching in a low-temperature hydrometallurgical process. Our investigation focused on elucidating the impact of substituents in the α position of hydroxy-carboxylic acids on copper solubilization efficacy.

Quantification of the Activator and Sensitizer Ion Distributions in NaYF :Yb , Er Upconverting Nanoparticles Via Depth-Profiling with Tender X-Ray Photoemission.

The spatial distribution and concentration of lanthanide activator and sensitizer dopant ions are of key importance for the luminescence color and efficiency of upconverting nanoparticles (UCNPs). Quantifying dopant ion distributions and intermixing, and correlating them with synthesis methods require suitable analytical techniques. Here, X-ray photoelectron spectroscopy depth-profiling with tender X-rays (2000-6000 eV), providing probe depths ideally matched to UCNP sizes, is used to measure the depth-dependent concentration ratios of Er to Yb , [Er ]/[Yb ], in three types of UCNPs prepared using different reagents and synthesis methods.

The Effect of the 3D Nanoarchitecture and Ni-Promotion on the Hydrogen Evolution Reaction in MoS /Reduced GO Aerogel Hybrid Microspheres Produced by a Simple One-Pot Electrospraying Procedure.

The transition toward renewable energy sources requires low-cost, efficient, and durable electrocatalysts for green H production. Herein, an easy and highly scalable method to prepare MoS nanoparticles embedded in 3D partially reduced (pr) graphene oxide (GO) aerogel microspheres (MoS /prGOAMs) with controlled morphology and composition is described. Given their peculiar center-diverging mesoporous structure, which allows easy access to the active sites and optimal mass transport, and their efficient electron transfer facilitated by the intimate contact between the MoS and the 3D connected highly conductive pr-GO sheets, these materials exhibit a remarkable electrocatalytic activity in the hydrogen evolution reaction (HER).

A DVD-MoS/AgS/Ag Nanocomposite Thiol-Conjugated with Porphyrins for an Enhanced Light-Mediated Hydrogen Evolution Reaction.

We have recently demonstrated in a previous work an appreciable photoelectrocatalytic (PEC) behavior towards hydrogen evolution reaction (HER) of a MoS/AgS/Ag nanocomposite electrochemically deposited on a commercial writable Digital Versatile Disc (DVD), consisting therefore on an interesting strategy to convert a common waster product in an added-value material. Herein, we present the conjugation of this MoS/AgS/Ag-DVD nanocomposite with thiol-terminated tetraphenylporphyrins, taking advantage of the grafting of thiol groups through covalent S-S bridges, for integrating the well-known porphyrins photoactivity into the nanocomposite. Moreover, we employ two thiol-terminated porphyrins with different hydrophilicity, demonstrating that they either suppress or improve the PEC-HER performance of the overall hybrid, as a function of the molecule polarity, sustaining the concept of a local proton relay.

Copper Vanadate Nanobelts as Anodes for Photoelectrochemical Water Splitting: Influence of CoO Overlayers on Functional Performances.

The design and development of environmentally friendly and robust anodes for photoelectrochemical (PEC) water splitting plays a critical role for the efficient conversion of radiant energy into hydrogen fuel. In this regard, quasi-1D copper vanadates (CuVO) were grown on conductive substrates by a hydrothermal procedure and processed for use as anodes in PEC cells, with particular attention on the role exerted by cobalt oxide (CoO) overlayers deposited by radio frequency (RF) sputtering. The target materials were characterized in detail by a multitechnique approach with the aim at elucidating the interplay between their structure, composition, morphology, and the resulting activity as photoanodes.

Visible Light Driven Photoanodes for Water Oxidation Based on Novel r-GO/β-Cu₂V₂O₇/TiO₂ Nanorods Composites.

This paper describes the preparation and the photoelectrochemical performances of visible light driven photoanodes based on novel r-GO/β-Cu₂V₂O₇/TiO₂ nanorods/composites. β-Cu₂V₂O₇ was deposited on both fluorine doped tin oxide (FTO) and TiO₂ nanorods (NRs)/FTO by a fast and convenient Aerosol Assisted Spray Pyrolysis (AASP) procedure. Ethylenediamine (EN), ammonia and citric acid (CA) were tested as ligands for Cu ions in the aerosol precursors solution.

Ag-Vanadates/GO Nanocomposites by Aerosol-Assisted Spray Pyrolysis: Preparation and Structural and Electrochemical Characterization of a Versatile Material.

In this article, we describe the deposition by aerosol-assisted spray pyrolysis of different types of silver vanadate nanocomposites with and without graphene oxide (GO) on different substrates (carbon paper (CP) and fluorine-doped tin oxide (FTO)). When deposited on CP, different amounts of GO were added to the Ag and V precursor solution to study the effect of GO on the physicochemical properties of the resulting Ag-vanadate. It is shown that the addition of GO leads mainly to the formation of nanoparticles of the AgVO phase, whereas AgVO and AgVO are obtained without the addition of GO.