Preparation and characterization of silver coated magnetic microspheres prepared by a modified electroless plating process

Degradation of sulfamethoxazole by cobalt-nickel powder composite catalyst coupled with peroxymonosulfate: Performance, degradation pathways and mechanistic consideration

In this work, cobalt-nickel powder (Co-NP) synthesized through electroless plating was used as a heterogeneous bimetallic catalyst for peroxymonosulfate (PMS) activation to degrade sulfamethoxazole (SMX) in the aqueous phase. Compared with different oxidation systems and different catalysts, it was proved that Co-NP had excellent catalytic ability, fast electron transfer rate and good stability. The effects of key parameters (initial pH, SMX concentration, catalyst and PMS dosages) on SMX degradation and ion leaching were studied in detail. Furthermore, the sensitivity of inorganic anions and different pollutants towards the Co-NP/PMS system was studied to investigate its application in natural water bodies. Quenching test showed that the main reactive oxygen species generated during the reaction were OH and SO₄^-, of which SO₄^- played a predominating role. Combined with XPS analysis, the activation mechanism was concluded that free radicals were mainly generated through the valence change of Co and Ni. Based on the seven intermediates measured through ultrahigh performance liquid chromatograph-mass spectrometry (UPLC-QTOF-MS/MS), the possible degradation pathways of SMX were proposed. Notably, this study provided a new kind of supporter for advanced oxidation processes and electroless plating technology.

Conformal Solution Deposition of Pt-Pd Titania Nanocomposite Coatings for Light-Assisted Formic Acid Electro-Oxidation

Many nanofabrication processes require sophisticated equipment, elevated temperature, vacuum or specific atmospheric conditions, templates, and exotic chemicals, which severely hamper their implementation in real-world applications. In this study, we outline a fully wet-chemical procedure for equipping a 3D carbon felt (CF) substrate with a multifunctional, titania nanospike-supported Pt-Pd nanoparticle (Pt-Pd-TiO₂@CF) layer in a facile and scalable manner. The nanostructure, composition, chemical speciation, and formation of the material was meticulously investigated, evidencing the conformal coating of the substrate with a roughened layer of nanocrystalline rutile spikes by chemical bath deposition from Ti³⁺ solutions. The spikes are densely covered by bimetallic nanoparticles of 4.4 ± 1.1 nm in size, which were produced by autocatalytic Pt deposition onto Pd seeds introduced by Sn²⁺ ionic layer adsorption and reaction. The as-synthesized nanocomposite was applied to the (photo)electro-oxidation of formic acid (FA), exhibiting a superior performance compared to Pt-plated, Pd-seeded CF (Pt-Pd@CF) and commercial Pt-C, indicating the promoting electrocatalytic role of the TiO₂ support. Upon UV-Vis illumination, the performance of the Pt-Pd-TiO₂@CF electrode is remarkably increased (22-fold), generating a current density of 110 mA cm^-2, distinctly outperforming titania-free Pt-Pd@CF (5 mA cm^-2) and commercial Pt-C (6 mA cm^-2) reference catalysts. In addition, the Pt-Pd-TiO₂@CF showed a much better stability, characterized by a very high poisoning tolerance for in situ-generated CO intermediates, whose formation is hindered in the presence of TiO₂. This overall performance boost is attributed to a dual enhancement mechanism (∼30% electrocatalytic and ∼70% photoelectrocatalytic). The photogenerated electrons from the TiO₂ conduction band enrich the electron density of the Pt nanoparticles, promoting the generation of active oxygen species on their surfaces from adsorbed oxygen and water molecules, which facilitate the direct FA electro-oxidation into CO₂.