Showing papers on "Sodium hypophosphite published in 2020"

New Versatile Synthetic Route for the Preparation of Metal Phosphate Decorated Hydrogen Evolution Photocatalysts

Abstract: Photocatalytic hydrogen generation will benefit from the realization of more active but less expensive cocatalysts compared with noble metal counterparts. Herein we developed a universal vapor deposition method that selectively uses the thermal decomposition products of sodium hypophosphite as a phosphorus source for the fabrication of inexpensive and highly efficient metal phosphate (MPi) modified CdS nanorods. We find that the modification with a bimetal phosphate (i.e., 5 wt % NiCoPi) leads to an activity enhancement by a factor of approximately 52 in boosting visible-light-driven hydrogen evolution relative to the pristine CdS nanorods. The photocatalyst exhibits a high hydrogen generation rate of 13.44 mmol·g-1·h-1, which is much higher than that of its single metal counterparts (NiPi, 8.70 mmol·g-1·h-1; CoPi, 5.79 mmol·g-1·h-1) and 1 wt % Pt modified CdS (1.33 mmol·g-1·h-1). Its apparent quantum efficiency reaches 23.5% at 420 nm. Furthermore, it also shows remarkable photostability for eight consecutive cycles of photocatalytic activity tests with total reaction time of 24 h. The excellent photocatalytic performance of the photocatalyst is believed to be associated with the in situ formed NiICoP and NiCoIIIPi cocatalysts, which not only play an important role in photogenerated charge separation but also provide highly active catalytic reaction sites for the corresponding hydrogen evolution reaction and the sacrificial agent oxidation reaction.

Isotherm and Kinetic Studies in Dyeing of Citric Acid-Crosslinked Cotton with Cationic Natural Dye

Abstract: In this study, cotton fabric was crosslinked with citric acid (CA) in the presence of sodium hypophosphite using a pad-dry-cure process under the optimum conditions. The chemistry and morphology of the crosslinked fibers were studied and compared with the untreated fibers using FTIR and SEM. The crosslinked fabric was dyed with the natural cationic dye, berberine, obtained from the roots of Berberis vulgaris. The effects of dyebath conditions, including dye concentration, pH, and temperature, on the color strength of the dyed samples were investigated, and the mean values were compared using SPSS. The isotherm and kinetics of the dyeing of the CA-treated fabric with berberine were investigated. The results showed that the color strength of the dyed samples increased with increasing the dye concentration, pH, and temperature. The best-fitting isotherm and kinetic models were Freundlich and pseudo-second-order models, respectively.

Facile, controllable, chemical reduction synthesis of copper nanostructures utilizing different capping agents

Abstract: This investigation reports a simple, controllable, chemical reduction method for the formation of copper nanoparticles by reducing copper sulfate with sodium hypophosphite in ethylene glycol using ...

Preparation and characterization of β-cyclodextrin grafted silk fabric

Abstract: Silk fabrics were treated by β-cyclodextrin (β-CD) in the presence of citric acid (CA) as crosslinking agent and sodium hypophosphite (SHP) as catalyst using pad dry cure technique. CA is expected ...

Role of Substrate in Au Nanoparticle Decoration by Electroless Deposition

Abstract: Decoration of nanostructures is a promising way of improving performances of nanomaterials. In particular, decoration with Au nanoparticles is considerably efficient in sensing and catalysis applications. Here, the mechanism of decoration with Au nanoparticles by means of low-cost electroless deposition (ELD) is investigated on different substrates, demonstrating largely different outcomes. ELD solution with Au potassium cyanide and sodium hypophosphite, at constant temperature (80 °C) and pH (7.5), is used to decorate by immersion metal (Ni) or semiconductor (Si, NiO) substrates, as well as NiO nanowalls. All substrates were pre-treated with a hydrazine hydrate bath. Scanning electron microscopy and Rutherford backscattering spectrometry were used to quantitatively analyze the amount, shape and size of deposited Au. Au nanoparticle decoration by ELD is greatly affected by the substrates, leading to a fast film deposition onto metallic substrate, or to a slow cluster (50–200 nm sized) formation on semiconducting substrate. Size and density of resulting Au clusters strongly depend on substrate material and morphology. Au ELD is shown to proceed through a galvanic displacement on Ni substrate, and it can be modeled with a local cell mechanism widely affected by the substrate conductivity at surface. These data are presented and discussed, allowing for cheap and reproducible Au nanoparticle decoration on several substrates.

Hydrogen Evolution Reaction Electrocatalysts Based on Electrolytic and Chemical-Catalytic Alloys of Rhenium and Nickel

Abstract: The composition, structure, and electrocatalytic properties in HER are compared for Re–Ni electrodeposits and Ni–Re–P alloys synthesized by chemical-catalytic deposition with the use of sodium hypophosphite as the reducer. The coordination numbers of nickel and rhenium and the interatomic distances of synthesized materials are determined by EXAFS and XANES methods. It is shown that the structure of Re‒Ni catalysts with the highest catalytic activity lacks the far order as regards the position of rhenium and nickel atoms, which allows assuming that these electrode materials are in the amorphous state. For chemical-catalytic Ni–Re–P coatings, it is shown that the introduction of rhenium into their composition lowers down the phosphorus content in the alloy formed. The chemical-catalytic Ni–Re–P coatings show promise as the HER catalysts in acid solutions.

Optimization of the Corrosion Resistance of Electroless Ni–W–P Coatings on Magnesium Alloys by the Response Surface Methodology

Abstract: Plating processes greatly affect the corrosion resistance of electroless Ni–W–P coatings on magnesium alloys. In the present research, the corrosion resistance of electroless Ni–W–P alloy-coated AZ91D magnesium alloy was optimized by the response surface methodology. The optimum technological parameters of the plating process were determined by establishing a quadratic regression model, and the influence of these variables and their interactions on the corrosion resistance of the coating was analyzed. The optimum technological parameters of the electroless plating process were nickel sulfate concentration = 20 g/L, sodium tungstate concentration = 15 g/L, sodium hypophosphite concentration = 30 g/L, bath temperature = 60 °C, and bath pH = 9.3. Under these conditions, the coating had the best corrosion resistance. Among the aforementioned five variables, sodium tungstate concentration had the most significant influence on the corrosion resistance of the coating. Different degrees of interactions among the variables greatly affected the corrosion resistance of the coating.

Phase-control synthesis and catalytic property of nickel phosphide nanospheres

Abstract: In this article, a mild hydrothermal route was developed to synthesize nickel phosphide nanostructures, using nickel chloride, sodium hypophosphite, and white phosphorus (WP) as reactants at 170 °C. The results indicated that the controllable phase of the prepared nickel phosphide nanostructures was highly dependent on the amount of sodium hypophosphite, WP, and reaction time. We also discovered that different phase nickel phosphide nanostructures have excellent catalytic properties for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in NaBH4. Simultaneously, similar aromatic nitro compounds 2-nitrophenol (2-NP) and 4-nitroaniline (4-NA) were further discussed. The experimental results demonstrated that the pure Ni2P phase has a better catalytic reduction of 4-NP than the pure Ni12P5 phase.

Volumetric Properties and Ion Interactions for Sodium Hypophosphite Aqueous Solution from 283.15 to 363.15 K at 101.325 kPa

Abstract: Densities of sodium hypophosphite aqueous solution (NaH2PO2) with the molality varied from 1.019143 to 10.43887 mol kg–1 at temperature intervals of 5 K range from 283.15 to 363.15 K at 101.325 kPa were measured by a precise Anton Paar Digital vibrating-tube densimeter. From the density data, the thermal expansion coefficients, apparent volume and partial molar volumes were obtained. According to the Pitzer ion-interaction equation of the apparent molar volumes, the Pitzer single-salt parameters and their temperature-dependent correlation for NaH2PO2 were firstly obtained by the least-squares method. The model shown that apparent molar volumes agree well with the experimental values, which indicated the single salt parameters and the temperature-dependent formula are reliable.

Method for synthesizing fine-granularity aluminum hypophosphite composite flame retardant

Abstract: The invention discloses a method for synthesizing a fine-granularity aluminum hypophosphite composite flame retardant. The method comprises: carrying out a double decomposition reaction at a temperature of 60-95 DEG C by using sodium hypophosphite and a water-soluble aluminum salt as raw materials, using water as a solvent, using diethyl aluminum hypophosphite as a seed crystal and using a surfactant as a product crystal form control agent to obtain a fine-granularity aluminum hypophosphite and diethyl aluminum hypophosphite compounded flame retardant product. According to the invention, the synthetic method is high in efficiency, low in cost and easy to operate; and the fine-granularity aluminum hypophosphite and diethyl aluminum hypophosphite compounded flame retardant synthesized by adopting the method disclosed by the invention can be directly obtained under the condition that conventional synthesis production is not changed, so that the cost is reduced, and the comprehensive competitiveness of the flame retardant as the compounded flame retardant is enhanced.

Preparation method of vanadium-doped nickel phosphide composite nitrogen-sulfur double-doped reduced graphene oxide electro-catalytic material

Abstract: The invention discloses a preparation method of a vanadium-doped nickel phosphide composite nitrogen-sulfur double-doped reduced graphene oxide electro-catalytic material. The preparation method comprises the following steps: 1) grinding graphene oxide and L-cysteine; 2) putting a mixture ground in step 1) into a tubular furnace to prepare nitrogen-sulfur double-doped reduced graphene oxide; 3) preparing a nitrogen-sulfur double-doped reduced graphene oxide solution with the concentration of 0.5-1.0 mg/mL; 4) adding urea, NH4F, vanadium chloride and a nickel salt into the nitrogen-sulfur double-doped reduced graphene oxide solution, and stirring until a uniform solution is formed; 5) transferring the solution in step 4) into a reaction kettle to prepare a precursor NiV-LDH/NSG; and (6) putting the precursor NiV-LDH/NSG material and sodium hypophosphite into a tubular furnace together, heating to 300-400 DEG C, and keeping the temperature to obtain the vanadium-doped nickel phosphide composite nitrogen-sulfur double-doped reduced graphene oxide electrocatalytic material NiVP/NSG. The preparation method is low in cost and simple, and the obtained electro-catalytic material has good OER.

Carbon-supported ruthenium phosphide nanocluster dual-functional catalyst, and preparation method and application thereof

Abstract: The invention discloses a carbon-supported ruthenium phosphide nanocluster dual-functional catalyst, and a preparation method and application thereof. The preparation method of the catalyst comprisesthe following steps: dispersing active carbon powder and an Ru precursor in water, carrying out stirring to ensure that the Ru precursor is fully adsorbed on the surface of the active carbon, then carrying out evaporating to remove moisture, mixing and grinding the obtained solid powder with sodium hypophosphite, placing the mixture in a tubular furnace, carrying out high-temperature calcination in an inert atmosphere to enable the Ru precursor supported on the active carbon and the sodium hypophosphite to react at high temperature to be converted into a ruthenium phosphide active component, washing the calcined product with water, and carrying out drying to obtain the carbon-supported ruthenium phosphide nanocluster dual-functional catalyst. The carbon-supported ruthenium phosphide nanocluster dual-functional catalyst disclosed by the invention can be used for catalyzing a hydrogenation reaction of quinoline and catalyzing a dehydrogenation reaction of 1,2,3,4-tetrahydroquinoline. Thecatalyst disclosed by the invention is high in catalytic activity and good in stability; and the preparation method of the catalyst is simple, and is easy for industrial mass production.

A Method for Electroless Nickel Plating on Aluminum Alloy Surface

Abstract: According to the following plating processes: deoiling → washing → pickling → washing → drying → weighing → electroless plating → washing → drying → weighing. It can obtain Ni-P deposit on aluminum alloy. It studied the influence of bath composition and process parameters on the composition and deposition rate of the alloy coating. Under temperature of 85~90°C, nickel sulfate hexahydrate 15~35g/L, sodium hypophosphite 10~30g/L, sodium citrate 5~10g/L, tartaric acid 1~2g/L, pH 3~5, reaction time 30~60min, load factor 1.0~2.0dm2/L. The microstructure, surface morphology, composition and valence of the elements in the alloy coating were studied by metallographic microscope, SEM, EDS and other modern analytical methods. The size of spherical grain was below 1um and compact distribution. The chemical coatings were mainly composed two elements, which were phosphorous and nickel. The mass percentage of phosphorous was about 15%, and the other one was about 80~85%. The corrosion resistance of the alloy coating was studied by CASS [1] test method, through 80h CASS test detection, the protection class of chemical coating can be reached 5. The relevant evaluation criteria can be referred to GB/T 6461-2002 [2]. The results show that the Ni-P binary amorphous alloy can be successfully prepared by this process.

Carbon-coated tungsten-doped metal phosphide and preparation method thereof

Abstract: The invention discloses a preparation method of a carbon-coated tungsten-doped metal phosphide material. The preparation method comprises the following steps: 1) taking tungsten chloride, metal organic salt and sodium hypophosphite as raw materials, adding absolute ethyl alcohol, and obtaining precursor powder through a ball milling method; and 2) carrying out heat treatment on the precursor powder in an inert atmosphere to obtain the carbon-coated tungsten atom-doped metal phosphide material. The general formula of the chemical components of the material prepared by the method is Wx-MPy/C, Wis a tungsten element, x is the molar ratio of tungsten atoms to M metal elements and ranges from 0.05 to 0.15, and M can be any one or combination of Co, Ni and Fe in any proportion. The tungsten-doped metal phosphide prepared by the method is composed of nanoparticles with the size of about 10-20 nm, and the surface of the tungsten-doped metal phosphide is coated with a carbon layer with the size of 2-3 nm. The preparation method has the characteristics of simple preparation process and uniform size of the obtained nanoparticles, and the prepared material can be applied to catalysts, supercapacitors, lithium ion batteries and the like.

Preparation of tin/tin phosphide/carbon composite material of alkali metal ion battery negative electrode

Abstract: The invention discloses preparation of a tin/tin phosphide/carbon composite material of an alkali metal ion battery negative electrode, which mainly comprises the steps of firstly, crosslinking sodiumalginate and tetravalent tin ions, then freeze-drying a crosslinking product by using sodium chloride as an inhibitor, carbonizing the product in an inert atmosphere, and then phosphating the productby using sodium hypophosphite to obtain the tin/tin phosphide/carbon composite material. According to the invention, nano-sized tin oxide particles are produced by a sodium alginate crosslinking method and wrapped by the graphitized carbon, a relatively good pore channel structure is formed in the macromolecular cracking process, the structure is reserved while the tin/tin phosphide/carbon composite material is obtained by using gaseous phosphating, so that the prepared composite material has good pore channels and conductivity, tin expansion can be effectively inhibited, and the tin/tin phosphide/carbon composite material has good cycle performance and rate capability when being applied to an alkali metal ion battery. The method is simple to operate, low in process cost and easy for industrial large-scale production.

Cu-Co-P composite material as well as preparation method and application thereof

Abstract: The invention relates to a Cu-Co-P composite material preparation method. The method comprises the following steps: dissolving a soluble copper salt and a soluble cobalt salt in water, carrying out ahydrothermal reaction, and carrying out centrifugation, washing and drying after the reaction is completed to obtain a Cu-Co precursor; mixing the Cu-Co precursor with sodium hypophosphite, and calcining the mixture in a protective atmosphere to obtain a Cu-Co-P composite material; and preparing the composite material into a working electrode which is used in a supercapacitor. Compared with the prior art, the Cu-Co-P composite material is synthesized through hydrothermal synthesis, the composite material contains rich mesopores and micropores so as to achieve good electrochemical performance,and the composite material has the advantages that the preparation method is simple and environmentally friendly, the synthesis time is greatly shortened, and large-scale production of the high-purityCu-Co-P composite material is facilitated.

Method for chemically plating NiP on surface of multi-walled carbon nanotube

Abstract: The invention discloses a method for chemically plating NiP on a surface of a multi-walled carbon nanotube The preparation method comprises the following steps: adding a multi-walled carbon nanotubeinto a chemical plating solution; uniformly dispersing, heating to not less than 85 DEG C, plating for a set time, and calcining in an inert atmosphere at not less than 400 DEG C, wherein a solute ofthe chemical plating solution is nickel sulfate, and the concentration of the nickel sulfate is 249-251 g/L in terms of NiSO46H2O; the concentration of the sodium citrate is 99 g/L to 101 g/L interms of Na3C6H5O72H2O; wherein the concentration of the sodium acetate is 99 g/L to 101 g/L in terms of CH3COONa3H2O; the concentration of the sodium hypophosphite is 199 g/L to 201 g/L in terms of NaH2PO2 Themethod has the advantages of no need of palladium catalysis, no need of pretreatment of carbon nanotubes, few types of raw materials and simple preparation process, and can be used asan electrocatalyst to improve the HER performance

Regeneration treatment method of chemical nickel plating solution

Abstract: The invention discloses a regeneration treatment method of an chemical nickel plating solution. The chemical nickel plating solution is contained into a reserved tank and then injected into a regeneration tank, a calcium hypophosphite solution is then added into the regeneration tank, stirring, standing and filtering are carried out to obtain first supernatant and first sediment, the first supernatant is reserved for later use, then the first sediment is washed, and a cleaning solution is collected and incorporated into the first supernatant; the calcium hypophosphite solution is added into the first supernatant, stirring, standing and filtering are carried out to obtain second supernatant and second sediment, then the second sediment is washed, a cleaning solution is collected and incorporated into the second supernatant, and the second supernatant is a regenerated chemical nickel plating crude solution; and nickel sulfate and sodium hypophosphite are added into the regenerated chemical nickel plating crude solution to obtain the regenerated chemical nickel plating solution. By means of the method, harmful ions including sulfate radicals and phosphite radicals are effectively removed, high-value substances such as nickel ions and hypophosphite ions are recovered, and recycling regeneration of a chemical nickel plating aging solution is realized.

Textile anti-radiation agent and preparation method thereof

Abstract: The invention discloses a fabric anti-radiation agent and a preparation method thereof, wherein the fabric anti-radiation agent comprises superfine kaolin, iron oxide, silicone foam resin, sodium hypophosphite, nickel sulfate, a softening agent, an essence and water, wherein by mass, the superfine kaolin accounts for 2-3 parts, the iron oxide accounts for 1-2 parts, the silicone foam resin accounts for 5-10 parts, the sodium hypophosphite accounts for 0.5 part, the nickel sulfate accounts for 0.5 part, the softening agent accounts for 1-2 parts, the essence accounts for 1-2 parts, and the water accounts for 10-20 parts. The preparation method of the textile anti-radiation agent comprises the steps of adding nickel sulfate and sodium hypophosphite into water, heating and stirring; adding superfine kaolin and iron oxide, and stirring; adding silicone foam resin, and stirring; and adding a softening agent and an essence, and stirring to obtain the anti-radiation agent. The textile anti-radiation agent and preparation method thereof have the advantages of good simplicity and convenience of operation, low cost, and wide-range applicability.

Efficient nickel phosphide water electrolysis and hydrogen evolution catalytic electrode under neutral condition, and preparation method thereof

Abstract: The invention provides an efficient nickel phosphide water electrolysis and hydrogen evolution catalytic electrode under a neutral condition, and a preparation method thereof. According to the electrode, foamed nickel is used as a substrate, a mixed solution of sodium hypophosphite, nickel sulfate, sodium borate, sodium fluoride, ferrous chloride salt and cobalt chloride is used as an electrolyticsolution, a platinum sheet is used as a counter electrode, an extremely small amount of a precious metal Pt is loaded on the surface of a catalyst through an electro-deposition method, the nickel salt in the electrolytic solution provides a nickel source needed by deposition, the sodium hypophosphite provides a phosphorus source, the platinum sheet naturally provides a platinum source in an anodeprocess, the porous foamed nickel serves as a carrier to facilitate the deposition of nickel phosphide, and in the process, the extremely small amount of the platinum from the platinum sheet is deposited on the porous foamed nickel; and an additive component provides a target element source for various doping, and plays a role in preparing hydrogen through synergistic catalysis. The prepared catalytic electrode has good water electrolysis and hydrogen evolution performance.

Preparation process of medium-temperature chemical nickel-phosphorus plating alloy on metal surface

Abstract: The invention discloses a preparation process of a medium-temperature chemical nickel-phosphorus plating alloy on a metal surface. The method comprises the steps of: weighing nickel sulfate, a bufferagent, lactic acid, inorganic acid, a rare earth brightener and a stabilizer according to a plating solution formula, adding water, performing stirring to dissolve and stand for more than 5 hours, filtering out insoluble substances, adding an additive, and performing stirring to dissolve to obtain a solution A; preparing a sodium hypophosphite solution, weighing the solution, adding a proper amount of water, performing stirring for dissolving, standing the solution for more than 5 hours, filtering out insoluble substances, and stirring the solution to obtain a solution B; and preparing the solution A and the solution B according to the proportion of 1:1, mixing and heating the prepared solution A and the prepared solution B together in a constant-temperature water bath kettle, wherein theheating temperature ranges from 60 DEG C to 68 DEG C, the heating time ranges from 1 hour, the PH value is adjusted to 5.0, and the plating working solution is obtained. A proper amount of sodium hypophosphite, boric acid and lactic acid are added into the basic plating solution, so that a prepared plated film is uniform and compact and is crystallized in a cellular structure, and the wear resistance and the corrosion resistance are improved.

Method for preparing optical fiber cladding optical filter based on Ni-P chemical plating method

Abstract: The invention provides a method for preparing an optical fiber cladding optical filter based on a Ni-P chemical plating method A metal Ni-P plating is prepared on the surface of an optical fiber witha coating layer removed through the Ni-P chemical plating technology, and main components of Ni-P chemical plating liquid comprise 8 to 10 g of citric acid, 20 to 30 ml of lactic acid, 25 to 30 g ofnickel sulfate, 25 to 30 g of sodium hypophosphite, the proper amount of a stabilizing agent, 6 to 8 g of sodium acetate, and 10 to 12 g of butanedioic acid The prepared metal Ni-P plating is good inquality, and is evenly deposited on the surface of the optical fiber with the coating layer removed, and due to the fact that the metal Ni-P is a good conductor in nature, the method overcomes the problems that for a traditional cladding optical filter, a large amount of cladding light is leaked, local temperature rapidly rises, and the optical filter is burnt out The cladding optical filter isuniform in whole temperature distribution, cladding light can be evenly stripped, and meanwhile, the higher corrosion resistance and hardness are achieved

Organic photocathode taking copper nanosheet as support skeleton and preparation method thereof

Abstract: The invention relates to an organic photocathode taking a copper nanosheet as a support skeleton and a preparation method thereof. The preparation method of the organic photocathode comprises the following steps: 1) preparing the copper nanosheet by adopting an electrodeposition method, to be more specific, adding soluble copper (II) salt, sodium hypophosphite, sodium citrate, boric acid and polyethylene glycol into deionized water, stirring to obtain a uniform copper salt solution, dropwise adding an alkaline aqueous solution into the copper salt solution, regulating the pH value of the solution to 7.5-9.5, and stirring for 5-10 minutes to obtain a solution I; pouring the solution I obtained in the step 1.1 into an electrolytic cell, carrying out electro-deposition for 25-35 minutes by using FTO plated with a copper seed layer to obtain a sample, washing the sample, and carrying out vacuum drying to obtain a copper nanosheet taking the FTO as a substrate; and 2) loading a hole transport layer and an organic absorption layer on a metal framework of the copper nanosheet taking the FTO as thesubstrate by adopting a spin-coating method to obtain the organic photocathode.