Sodium hypophosphite

About: Sodium hypophosphite is a research topic. Over the lifetime, 1695 publications have been published within this topic receiving 15932 citations.

Large-scale synthesis of copper nanoparticles by chemically controlled reduction for applications of inkjet-printed electronics.

Abstract: Copper nanoparticles are being given considerable attention as of late due to their interesting properties and potential applications in many areas of industry. One such exploitable use is as the major constituent of conductive inks and pastes used for printing various electronic components. In this study, copper nanoparticles were synthesized through a relatively large-scale (5 l), high-throughput (0.2 M) process. This facile method occurs through the chemical reduction of copper sulfate with sodium hypophosphite in ethylene glycol within the presence of a polymer surfactant (PVP), which was included to prevent aggregation and give dispersion stability to the resulting colloidal nanoparticles. Reaction yields were determined to be quantitative while particle dispersion yields were between 68 and 73%. The size of the copper nanoparticles could be controlled between 30 and 65 nm by varying the reaction time, reaction temperature, and relative ratio of copper sulfate to the surfactant. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) images of the particles revealed a spherical shape within the reported size regime, and x-ray analysis confirmed the formation of face-centered cubic (FCC) metallic copper. Furthermore, inkjet printing nanocopper inks prepared from the polymer-stabilized copper nanoparticles onto polyimide substrates resulted in metallic copper traces with low electrical resistivities (≥3.6 µΩ cm, or ≥2.2 times the resistivity of bulk copper) after a relatively low-temperature sintering process (200 °C for up to 60 min).

P-doped tubular g-C3N4 with surface carbon defects: Universal synthesis and enhanced visible-light photocatalytic hydrogen production

Abstract: Hetero-element doping or vacancy defects of g-C3N4 framework were found significantly to control its electronic structure and enhance photocatalytic activity under visible light. Herein, we fabricated P-doped tubular g-C3N4 (P-TCN) with surface carbon defects wherein the P-doping and carbon defects were conveniently introduced during thermal polymerization of a supramolecular precursor. The supramolecular precursor of rod-like morphology was obtained only from melamine molecules under a sodium pyrophosphate-assisted hydrothermal process. As contrast, similar P-doped g-C3N4 tubes were obtained using other phosphates, such as ammonium phosphate, sodium hypophosphite and sodium phosphite, thus highlighting the versatility of this method to tune the morphology and C/N ratio for g-C3N4 tubes. The photocatalytic activities of P-TCNs were evaluated using hydrogen evolution from water under visible light. Among these, P-TCN obtained by sodium pyrophosphate-assisted hydrothermal reaction showed the highest photocatalytic activity due to high P element doping, enhanced visible light absorption and improved charge separation. The novel synthetic method described here thus represents an effective way of non-metal doping and C/N ratio tuning of g-C3N4 with excellent photocatalytic performance.

Nanocrystalline Manganese Oxides for Electrochemical Capacitors with Neutral Electrolytes

Abstract: With an objective to develop inexpensive electrode materials for electrochemical redox capacitors, nanocrystalline manganese oxides have been synthesized by reducing aqueous KMnO 4 solution with various reducing agents such as potassium borohydride, sodium dithionite, sodium hypophosphite, and hydrochloric acid under various controlled pH conditions. The products have been characterized by X-ray diffraction, thermogravimetric analysis, surface area measurements, and cyclic voltametry in various neutral electrolytes such as aqueous NaCI, KCl, LiCI, and Na 2 SO 4 . Optimized samples exhibit specific capacitance values of around 250 F/g in the range of 0-1 V vs. SCE with excellent cyclability in 2 M NaCI electrolyte.

Effect of coating time and heat treatment on structures and corrosion characteristics of electroless Ni-P alloy deposits

Abstract: Mild steel was electroless coated with nickel–phosphorus alloy from a bath containing sodium hypophosphite and glycin–citrate complexing agents. The effect of coating time on phosphorus content, thickness, structure and hardness of the deposits were analyzed. Corrosion parameters such as current density, corrosion potential and corrosion rate were obtained from tafel polarization curves and immersion corrosion tests in aerated 3.5% NaCl solution. The X-ray diffraction (XRD) patterns, anodic polarization curves and scanning electron microscopy (SEM) of heat-treated specimens obtained in various coating times were also studied. The X-ray diffraction patterns showed that by changing the coating times, amorphous or crystalline structure could be obtained. The coatings containing 11.1–13.1% phosphorous were amorphous, and showed better corrosion resistance than microcrystalline structure. The heat-treated specimens obtained in different coating time had more hardness and corrosion resistance than unheated samples. According to the polarization studies and scanning electron microscopy images, the heat-treated samples with 10.8 and 10.1% phosphorous show the intergranular corrosion, while the coatings with 11.7 and 12.2% of phosphorus have the least corrosion rate. Immersion corrosion test data at the 4-month interval had good agreement with electrochemical polarization results.