Zero-Valent Iron Nanoparticles with Unique Spherical 3D Architectures Encode Superior Efficiency in Copper Entrapment

The large-scale preparation of spherical condensed-type superstructures of zero-valent iron (nZVI), obtained by controlled solid-state reaction through a morphologically conserved transformation of a magnetite precursor, is herein reported. The formed 3D nanoarchitectures (S-nZVI) exhibit enhanced entrapment efficiency of heavy metal pollutants, such as copper, compared to all previously tested materials reported in the literature, thus unveiling the relevance in the material’s design of the morphological variable. The superior removal efficiency of these mesoporous S-nZVI superstructures is linked to their extraordinary ability to couple effectively processes such as reduction and sorption of the metal pollutant

Templated Dewetting–Alloying of NiCu Bilayers on TiO₂ Nanotubes Enables Efficient Noble-Metal-Free Photocatalytic H₂ Evolution

Photocatalytic H₂ evolution reactions on pristine TiO₂ is characterized by low efficiencies that are due to trapping and recombination of charge carriers and due to a sluggish kinetics of electron transfer. Noble-metal (mainly Pt, Pd, Au) nanoparticles are typically decorated as co-catalysts on the TiO₂ surface to reach reasonable photocatalytic yields. However, because of the high cost of noble metals, alternative metal co-catalysts are being developed. Here, we introduce an approach to fabricate an efficient noble-metal-free photocatalytic platform for H₂ evolution based on alloyed NiCu co-catalytic nanoparticles at the surface of anodic TiO₂ nanotube arrays. NiCu bilayers are deposited onto the TiO₂ nanotubes by plasma sputtering. A subsequent thermal treatment is carried out that leads to dewetting, that is, because of surface diffusion, the Ni- and Cu-sputtered layers simultaneously mix with each other while splitting into NiCu nanoparticles at the nanotube surface. The approach allows for a full control over key features of the alloyed nanoparticles, such as their composition, work function, and co-catalytic ability toward H₂ generation. Dewetted–alloyed co-catalytic nanoparticles composed of equal Ni and Cu amounts not only are significantly more reactive than pure Ni or Cu nanoparticles, but also lead to H₂ generation rates that can be comparable to those obtained by conventional noble-metal (Pt) decoration of TiO₂ nanotube arrays

Functional Nanosheet Synthons by Covalent Modification of Transition-Metal Dichalcogenides

We report on the facile preparation of versatile MoS₂–thiobarbituric acid conjugates, which, in addition to excellent electrochemical behavior, can serve as nanosheet platforms for further functionalization in a multitude of applications. We show that chemically exfoliated MoS₂ was extensively modified with up to 50% surface coverage, while maintaining its metallic character, and that the strategy can be extended to MoSe₂, WS₂, and WSe₂. The covalent functionalization endowed the materials not only with good aqueous dispersibility, but also with improved hydrogen evolution reaction (HER) activity, as well as promise in the oxidative detection of DNA nucleobases in solution