Amorphous NiFe Nanotube Arrays Bifunctional Electrocatalysts for Efficient Electrochemical Overall Water Splitting

It is still a challenge for design and fabrication of cost-effective and efficient bifunctional electrocatalysts for both cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) for overall water splitting. Herein, we design and synthesize amorphous NiFe nanotube arrays on nickel foam (NiFe NTAs-NF) with high electrocatalytic activity and excellent durability for both OER and HER in overall water splitting. The as-synthesized NiFe NTAs-NF only requires relatively low overpotentials of 216 mV for the OER and 181 mV for the HER to reach current densities of 50 and 10 mA cm^–2, respectively. Moreover, when used as bifunctional catalysts for water splitting, the designed electrode only needs a low cell voltage of 1.62 V to obtain 10 mA cm^–2 for the overall water splitting, with an extremely excellent durability. The excellent performance of the NiFe NTAs-NF might be attributed to the synergistic effect and amorphous phase of NiFe alloy as well as the well-defined nanotube array architecture with large surface area, abundant active sites, and sufficient gas and electrolyte diffusion channels

Sn-Nanorod-Supported Ag Nanoparticles as Efficient Catalysts for Electroless Deposition of Cu Conductive Tracks

The applications of tin are extremely wide-ranging, in fields as diverse as Li-ion batteries, catalysis, and electronic packaging. It is always significant but still remains a great challenge to develop facile and efficient routes to synthesize Sn nanostructures. Herein, we report a facile chemical method to synthesize a Sn nanorod crystal at room temperature, and Ag ions are subsequently introduced to form the Sn-nanorod-supported Ag nanoparticles hybrid structure (Sn/Ag nanorods). The Sn/Ag nanorods exhibit comparable activity to the commercial Pd black in catalyzing the electroless copper deposition (ECD) reaction that is indispensable to fabricate printed circuit boards (PCBs). Furthermore, a screen printable adhesive is prepared by mixing the as-synthesized Sn/Ag nanorod powders and epoxy resin to fabricate activator patterns on epoxy laminate (EPL) and flexible substrates including polyethylene terephthalate (PET) and polytetrafluoroethylene (PTFE) fiber film. The printed areas are finally metalized by the ECD process to obtain the copper coatings with designed patterns that are confirmed to exhibit excellent electrical conductivity and flexibility

Electroless Deposition Metals on Poly(dimethylsiloxane) with Strong Adhesion As Flexible and Stretchable Conductive Materials

A new surface modification method is developed for electroless deposition of robust metal (copper, nickel, silver) layers on poly­(dimethylsiloxane) (PDMS) substrate with strong adhesion. Under the synergies of the polydopamine (PDA), the plasma process enhances Ag⁺ reduction, and a thin Ag film is capable of tightly attaching to the PDMS surface, which catalyzes electroless deposition (ELD) to form robust metal layers on the PDMS surface with strong adhesion. Subsequently, a flexible and stretchable Cu-PDMS conductor is obtained through this method, showing excellent metallic conductivity of 1.2 × 10⁷ S m^–1, even at the longest stretch strain (700%). This process provides a successful strategy for obtaining good robust metal layers on PDMS and other polymer substrate surfaces with strong adhesion and conductivity

Phase-Transition-Induced Surface Reconstruction of Rh₁ Site in Intermetallic Alloy for Propane Dehydrogenation

The fine-tuning of the geometric and electronic structures of active sites plays a crucial role in catalysis. However, the intricate entanglement between the two aspects results in a lack of interpretable design for active sites, posing a challenge in developing high-performance catalysts. Here, we find that surface reconstruction induced by phase transition in intermetallic alloys enables synergistic geometric and electronic structure modulation, creating a desired active site microenvironment for propane dehydrogenation. The resulting electron-rich four-coordinate Rh1 site in the RhGe0.5Ga0.5 intermetallic alloy can accelerate the desorption of propylene and suppress the side reaction and thus exhibits a propylene selectivity of ∼98% with a low deactivation constant of 0.002 h–1 under propane dehydrogenation at 550 °C. Furthermore, we design a computational workflow to validate the rationality of the microenvironment modulation induced by the phase transition in an intermetallic alloy

Bowl-Like and Apple-Like PdCu Hollow Microparticles with Mesoporous Nanoshells: Synthesis, Characterization, and Electrocatalytic Performance

Novel bowl-like, apple-like, and spherical PdCu alloy hollow microparticles with mesoporous nanoshells are synthesized through a simple disproportionation reaction route using a spherical Cu₂O template with increasing H₂PdCl₄ ratio. The diameter of hollow particles is about 1 μm, and the thickness of mesoporous shells is about 50 nm. The obtained bowl-like PdCu alloy hollow microparticles with mesoporous nanoshells exhibit the highest electrocatalytic activity among the apple-like and spherical PdCu hollow microparticles and commercial Pd/C electrocatalysts toward methanol anodic oxidation for fuel cells. The remarkably excellent electrocatalytic performance of bowl-like PdCu alloy electrocatalysts might be attributed to the unique bowl-like hollow architecture with highly mesoporous nanoshells which are constructed by self-supported PdCu nanoparticles. The strategy presented here might help pave the way for the synthesis of novel nano-/microcomplex hollow materials with mesoporous nanoshells

One-Step Preparation of Silver Hexagonal Microsheets as Electrically Conductive Adhesive Fillers for Printed Electronics

A facile one-step solution-phase chemical reduction method has been developed to synthesize Ag microsheets at room temperature. The morphology of Ag sheets is a regular hexagon more than 1 μm in size and about 200 nm in thickness. The hexagonal Ag microsheets possess a smoother and straighter surface compared with that of the commercial Ag micrometer-sized flakes prepared by ball milling for electrically conductive adhesives (ECAs). The function of the reagents and the formation mechanism of Ag hexagonal microsheets are also investigated. For the polyvinylpyrrolidone (PVP) and citrate facet-selective capping, the Ag atoms freshly reduced by N₂H₄ would orientationally grow alone on the {111} facet of Ag seeds, with the synergistically selective etching of irregular and small Ag particles by H₂O_2, to form Ag hexagonal microsheets. The hexagonal Ag microsheet-filled epoxy adhesives, as electrically conductive materials, can be easily printed on various substrates such as polyethylene terephthalate (PET), epoxy, glass, and flexible papers. The hexagonal Ag microsheet filled ECAs demonstrate lower bulk resistivity (approximately 8 × 10^–5 Ω cm) than that of the traditional Ag micrometer-sized-flake-filled ECAs with the same Ag content of 80 wt % (approximately 1.2 × 10^–4 Ω cm)