Presence Of Sodium Hypophosphite Research Articles

Improvement of electrocatalytic alcohol oxidation by tuning the phase structure of atomically ordered intermetallic Pd-Sn nanowire networks

Atomically ordered intermetallic compounds (OICs) have aroused remarkable interests for wide applications and are considered as very promising materials for electrocatalysis owing to the strict stoichiometry, well-defined atom binding environment, and the specific crystalline phase. However, the tunable synthesis of the intermetallics remains a giant challenge. Herein, this study reports the preparation of the Pd-Sn OICs composed of an interconnected nanowire network structure with adjustable molar ratios of elements Pd and Sn. The co-reduction of Pd(acac)2 and SnCl2·2H2O in ethylene glycol (EG) in the presence of sodium hypophosphite (NaH2PO2) as the reducing agent affords OICs of three phases: hexagonal Pd3Sn2-P63/mmc, orthorhombic PdSn-Pnmb, and orthorhombic PdSn2-Aba2. Also, the pure phase can convert to two mixed phases (Pd3Sn2/PdSn and PdSn/PdSn2) by just altering the feed ratio. It is found that orthorhombic PdSn-Pnmb OIC has a large electrochemically active surface area (ECSA), excellent electrocatalytic performance (4857 mA mgPd−1), and outstanding stability toward ethanol oxidation reaction (EOR), which could be attributed to its optimal electronic structure. These results demonstrate that the phase engineering of OICs with desired components is an excellent way for catalysts design.

Synthesis of carbon-modified cobalt disphosphide as anode for sodium-ion storage

Phosphorus-rich metal phosphides have a high theoretical sodium-ion storage capacity. For example, cobalt disphosphide (CoP2) possesses a theoretical sodium-ion storage capacity of about 1330 mAh g−1, while the theoretical capacity of cobalt phosphide (CoP) is about 893 mAh g−1. However, it is currently challenging to synthesise phosphorus-rich metal phosphides. Herein, we report the synthesis of phosphorus-rich rod-like cobalt disphosphide with a carbon shell (CoP2@C) by thermal decomposition of polydopamine-coated cobalt oxalate in the presence of sodium hypophosphite. The as-obtained CoP2@C anode delivered a high sodium-ion storage capacity of ∼550 mAh g−1 at 500 mA g−1 due to its multi pseudocapacitive and intercalation charge storage mechanisms. These preliminary results show that CoP2@C hold a great promise for developing high-performance electrochemical energy storage devices based on sodium-ion as the charge carrier.

Selective reduction of aromatic halonitroarene to corresponding amine with Ru-gC3N4 as a catalyst in presence of sodium hypophosphite as a hydrogen source

This study reports an efficient heterogeneous catalyst Ru-gC3N4 (Ru-GCN) developed for the selective hydrogen transfer reduction reaction of nitroarenes to the corresponding amine. It helps to avoid multistep reaction in the field of organic synthesis. The catalyst Ru-gC3N4 shows excellent activity under the mild reaction parameters via using sodium hypophosphite as a hydrogen source and can be effective after many cycles without significant change in activity. The simply separable and recyclable heterogeneous Ru-gC3N4 catalyst is straight forward to operate, non-toxic, eco-friendly and at the same time replaces the comprehensive use of high pressurized hydrogen cylinder. Various types of material characterization and spectral methods such as PXRD, FTIR, SEM, TEM, XPS, and TGA are used to characterize the Ru-gC3N4 catalyst. All these properties such as good reusability and retained activity make our process sustainable and environmentally friendly. Aiming towards industrial potentiality, a gram scale experiment was reported using the developed protocol.

CoP/Co2P hollow spheres embedded in porous N-doped carbon as highly efficient multifunctional electrocatalyst for Zn–air battery driving water splitting device

Highly efficient multifunctional earth-abundant elements based electrocatalysts are key important for development of clean energy transformation technologies, such as metal-air batteries, fuel cells and water electrolysis. Herein, composite catalysts of N-doped carbon wrapping CoxP hollow spheres have been successfully prepared by pyrolysis of precursors from self-assembly of cobalt salt, terephthalic acid and PVP followed by carbonization and phosphatization in the presence of sodium hypophosphite. The resulted composites showed high specific surface areas, pore volumes and nitrogen contents, especially more than 47% of pyridinic-N. The electrocatalytic activity tests showed that the optimized CoxP-NC-420 sample exhibited superior multifunctional performances and high stabilities for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) under alkaline conditions. A low overpotential of 125/273 mV (at 10 mA cm−2) and Tafel slope of 66/81 mV dec−1 was obtained for HER and OER, respectively. As for ORR, as high as 0.860 V of half-wave potential was obtained, which is even 36 mV higher than that of Pt/C (20%). The catalyst also exhibited high practical performances on water electrolysis and Zn−air battery. Only 1.61 V of cell voltage was needed to reach 10 mA cm−2 for water electrolysis, and 1.374 V of open-circuit potential and 52 mW cm−2 of power density were obtained for Zn−air battery, which was 16 mW cm−2 higher than that of Pt/C (20%). Moreover, a highly effcient self-driven water electrolyzer has been designed with CoxP-NC-420 as both anode and cathode catalyst, powered by two-series-connected CoxP-NC-420-based Zn–air batteries. This work provides a new strategy for fabrication of non-precious multifunctional electrocatalysts.

A temperature-dependent phosphorus doping on Ti3C2Tx MXene for enhanced supercapacitance

A novel type of phosphorus doped Ti3C2Tx MXene nanosheets (P-Ti3C2Tx) is synthesized via a facile and controllable strategy of annealing MXene nanosheets with the presence of sodium hypophosphite. A combination of theoretical density functional theory calculation and experimental X-ray photoelectron spectroscopy discloses that the doped P atoms are prone to fill into Ti vacancies first due to their lowest formation free energy (ΔGP* = −0.028 eV·Å−2) and next to bond with surface terminals on MXene layers (ΔGP* = 0.013 eV·Å−2), forming P-C and P-O species, respectively. More importantly, the as-obtained P-Ti3C2Tx is, for the first time, investigated as the electrode material for supercapacitors, demonstrating a significantly boosted electrochemical performance by P doping. As a result, P-Ti3C2Tx electrode delivers a high specific capacitance of 320 F·g−1 at a current density of 0.5 A·g−1 (much higher than 131 F·g−1 for undoped MXene), an ultrahigh rate retention of 83.8% capacitance at 30 A·g−1, and a high cycling stability over continuous 5000 cycles.

Evaluation of Enhanced UV Protection Property of Dyed Cotton Fabrics Based on Inclusion Complex of β-cyclodextrin with Natural Coumarin Extracted from Cortex fraxini

Inclusion complex formed between β-cyclodextrin (β-CD) and natural coumarins extracted from Cortex fraxini were utilized to dye and enhancing the UV protection properties of cotton fabric. Natural coumarins were extracted from Cortex fraxini and the total amount of natural coumarins was evaluated. The inclusion complex of natural coumarins with β-CD were formed and analyzed by ultraviolet-visible spectrum, fluorescence spectroscopy, FTIR and TGA. The obtained results showed that a stoichiometry of 1:1 inclusion complex was formed and the fluorescence intensities and ultraviolet absorption of the natural coumarins were both enhanced by incorporating into β-CD. β-CD was grafted onto cotton fabric based on esterification of citric acid with cellulose and cyclodextrin in the presence of sodium hypophosphite. The grafted cotton fabric was then dyed with natural coumarins extraction of Cortex fraxini as natural ultraviolet absorbent to form stable inclusion complex. UV protection factor (UPF), UVA transmittance (TUVA) and UVB transmittance (TUVB), wrinkle recovery and tensile strength of dyed fabrics were evaluated and demonstrated that graft modification of fabrics with β-CD resulted enhancement in UV protection property and durability accompanied with increasing in wrinkle recovery properties and decreasing in tensile strength. Furthermore, apparent morphology, FTIR and TGA analysis of inclusion complexes loaded cotton fabrics and the relationship between structure and properties were investigated.

Simultaneous Dyeing and Finishing of Cotton Fabric in Presence of Starch Nanoparticles as Reinforcement Agent Using Citric Acid Based Finishing Formulation

ABSTRACT To augment high performance, coloration and functional finishing onto cotton fabrics; novel approach for simultaneous dyeing and finishing in addition to reinforcement effect were applied by conventional pad-dry-cure method in one step. This was done to explore the potential of reduction in energy consumption and production time as well as dyes and chemicals. For this purpose, our previously prepared starch nanoparticles (SNPs) as a reinforcement biopolymer were incorporated in cross-linking formulation of cotton fabrics embracing different concentrations of citric acid and cationic dyes, i.e., Methylene Blue and Crystal Violet in presence of sodium hypophosphite as a proficient catalyst at 1500C for 2 minutes. Evaluation of the treated fabric performance with respect to color strength (K/S), fastness properties to light, rubbing and perspiration, add on %, dry wrinkle recovery angles, tensile strength, fabric stiffness, antibacterial effect and ultraviolet protection factor were appraised. It is seen from the obtained results that; the simultaneously dyed and finished fabric in presence of SNPs showed higher color strength, dry wrinkle recovery angle, tensile strength, fabric stiffness, antibacterial and UPF functionalities in addition to considerable light, rubbing and perspiration fastness in comparison with untreated fabric. Besides, FTIR spectra exhibited the chemical structure of treated fabrics with respect to the presence of the ester crosslinking and functional groups of cationic dyes in questions in comparison with untreated fabric. The durability of the imparted functional properties was confirmed also by washing test.

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

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.

Anti-ultraviolet properties of β-cyclodextrin-grafted cotton fabrics dyed by broadleaf holly leaf extract

The aim of the study was to investigate the anti-ultraviolet properties of β-cyclodextrin-grafted cotton fabrics dyed with broadleaf holly leaf extract. Flavonoids were extracted from broadleaf holly leaf by maceration and a stoichiometry of 1:1 inclusion complex with β-cyclodextrin was formed. Characterized by the fluorescence spectrum and ultraviolet spectrophotometry, the fluorescence intensities and ultraviolet absorption of the macerated extract were enhanced by increasing the amount of cyclodextrin. Cotton fabrics were grafted with β-cyclodextrin through a crosslinking reaction based on citric acid in the presence of sodium hypophosphite then dyed with the macerated extract of broadleaf holly leaf used as a natural ultraviolet absorbent. The anti-ultraviolet property of fabrics dyed by a macerated extract was characterized in terms of the ultraviolet protection factor. It was noted that the cotton fabrics grafted with β-cyclodextrin exhibit enhanced anti-ultraviolet and wrinkle recovery properties compared to the unmodified samples and show an excellent durability against 30 washing cycles, accompanied by a loss of tensile strength.

β-Cyclodextrin assisted simultaneous preparation and dyeing acid dyes onto cotton fabric

Acid dyes are applied onto the cellulosic textiles through the modification of the textile surfaces with cationic groups. The conventional dyeing of the cellulosic textiles with acid dyes is usually performed over two main steps including, the preparation of the acid dyes and then the applying of these prepared dyes onto modified cellulosic textiles. Herein, a new strategy for simultaneous preparation and dyeing of the cotton fabrics with acid dyes in one step was developed. The innovative strategy was involved in two steps. The first step: β-CDs were grafted onto cotton fabrics through citric acid in the presence of sodium hypophosphite as catalyst and subsequently, the β-CDs grafted cotton fabrics were loaded with naphthols. In the second step; the acid dyes were formed directly onto the modified fabrics by the in-situ coupling of the diazonium salt of the different amines with the naphthols/β-CDs grafted cotton fabrics complexes. The amounts of the grafted β-CDs on the cotton fabrics were evaluated by qualitative and quantitative methods. The cotton fabrics were evaluated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Finally, the coloration and fastness properties of the dyed modified cotton fabrics were investigated. The results displayed that, the dyed modified cotton fabrics were shown the different color shades according to the naphthols and amines with remarkable fastness properties.

Effect of current density on electrodeposited cobalt ferrous tungsten phosphorus magnetic thin films

The properties of Co-Fe-W-P magnetic thin films electrodeposited in the presence of sodium hypophosphite as a precursor with varying concentrations were studied with respect to thickness of the films. Films were electrodeposited in various current densities in order to get different thickness and uniform deposits. Vibrating sample magnetometer studies indicate the magnetic saturation (Ms), retentivity (Mr) and coercivity (Hc) of these films. Crystallite size and dislocation density of Co-Fe-W-P thin films were calculated by X-ray diffraction studies. Surface morphology analysis was carried out by using Scanning Electron Microscope. Percentages of elemental analysis of Co-Fe-W-P thin films were obtained by using energy dispersive X-ray analysis. Hardness and adhesion of the films were also studied. Difference in magnetic properties and structural characteristics are discussed.

Two-dimensional correlation infrared spectroscopy of heat-induced esterification of cellulose with 1,2,3,4-butanetetracarboxylic acid in the presence of sodium hypophosphite

The heat-induced esterification reaction between cellulose and 1,2,3,4-butanetetracarboxylic acid (BTCA), catalyzed with sodium hypophosphite (SHP) was investigated by FTIR spectroscopy in combination with the perturbation correlation moving window (PCMW) technique and two-dimensional correlation Infrared spectroscopy (2Dcos). Two main stages could be identified in the heating process between 30 and 160 °C for the reaction system. Weakening of hydrogen bonding interactions within polar groups, such as C=O and O–H, and water evaporation takes place in the first stage (30–100 °C). The reaction process, which consists of cyclic anhydride formation and esterification, between BTCA and cellulose gradually occurs after heating above 100 °C. It is believed that both the presence of SHP and heating, leading to hydrogen bond breakage, contribute to the formation of cyclic anhydrides and further esterification. Moreover, it is shown in the 2Dcos analysis that ester groups appear immediately after the formation of anhydrides, suggesting that the reaction happens in a progressive way. Furthermore, through PCMW maps, we find that the esterification reaction mainly occurs in the temperature region between 126 and 142 °C and is fastest at 132 °C.

Thermal and flame retardant behaviour of cotton fabrics treated with a novel nitrogen-containing carboxyl-functionalized organophosphorus system

In this paper, a carboxyl-functionalized organophosphorus oligomer was immobilized onto cotton fabrics using 1,2,3,4-butanetetracarboxylic acid as an environmentally-friendly binder, in the presence of sodium hypophosphite, used as a catalyst, and triethanolamine, which contributes to phosphorous-nitrogen synergism. Moreover, with the aim of reducing the formation of insoluble calcium salt during home laundering, due to the free carboxylic acid groups bound to the cotton fabric, the treated samples were recoated employing three sol-gel precursors, namely 3-aminopropyltriethoxysilane, tetraethoxysilane and 3-glycidyloxypropyltriethoxysilane. Samples were thoroughly characterized to understand the bonding between coatings and substrate, as well as the related surface morphology. The thermal behaviour was investigated by thermogravimetric analysis, flame and combustion tests. The results revealed that the treated fabrics were able to achieve self-extinction. Comparing to the untreated sample, tearing strength of PMIDA/BTCA/SHP fabric was reduced in both warp and weft directions, while fabrics coated with an additional sol-gel layer were affected more significantly.

β-NiS modified CdS nanowires for photocatalytic H2 evolution with exceptionally high efficiency.

Co-catalysis is regarded as a promising strategy to improve the hydrogen evolution performance of semiconductor-based photocatalysts. But developing a simple and effective technique to achieve the optimal synergy between co-catalysts and host photocatalysts has been a great challenge. Herein, hybrid photocatalysts consisting of β-NiS modified CdS nanowires (NiS/CdS NWs) have been synthesized via a simple and green hydrothermal route using CdS NWs as the template from thiourea and nickel acetate in the presence of sodium hypophosphite. As a result, a metal Ni intermediate was formed via an electroless plating process assisted by H2PO2-, which facilitated the growth of highly conducting flake-like β-NiS nanostructures onto the surface of the CdS NWs. With the optimal loading amount of NiS, the obtained NiS/CdS NWs present a record-high photocatalytic activity for H2 evolution in lactic acid aqueous solutions under visible light irradiation. At 25 °C, the rate of H2 evolution was measured as 793.6 μmol h-1 (over a 5 mg photocatalyst sample), which is nearly 250-fold higher than that over pure CdS NWs, and the apparent quantum yield reached an exceptionally high value of 74.1% at 420 nm. The mechanism for the photocatalytic H2 evolution over the present NiS/CdS NWs was also proposed. This strategy would provide new insight into the design and development of high-performance heterostructured photocatalysts.

Antibacterial properties of silk fabric treated with Aloe Vera and silver nanoparticles

Silk is one of the important textile fibres used in apparel application. Since it is hygroscopic proteinous fibre, it is affected by microbes during usage and storage. Hence, antimicrobial treatment is desired to contain with this problem. Antimicrobial treatment is done using natural and synthetic agents. Nanoparticles have been added as antimicrobial agent for the application. In the present work, composite treatment of silk with Aloe Vera– a natural product and silver nanoparticles is done through crosslinking of 1,2,3,4-butane tetra carboxylic acid (BTCA) with silk in the presence of sodium hypophosphite (SHP). Effect of varying the concentration of BTCA, Aloe Vera and silver nanoparticles has been investigated. Untreated and treated silk fabrics have been characterized by FTIR, SEM and XRD to elucidate the effect of the treatment in terms of binding of Aloe Vera and silver nanoparticles, morphological changes and degree of crystallinity. Mechanical properties have been evaluated and analysed to illustrate the effect of the treatment. Further, the antimicrobial properties of the treated samples were evaluated against S. aureus (gram positive) and K. pneumoniae (gram negative) bacteria and the antimicrobial activity is found to be excellent. In order to assess the durability of the treatment, dry-cleaning has been done and subsequently antimicrobial properties have been assessed. Treated silk fabric samples after dry-cleaning upto 5 cycles exhibited satisfactory antimicrobial activity indicating that the treatment is durable in all the recipes. It is inferred that Aloe Vera chemically binds with silk through BTCA crosslinking while silver nanoparticles get adhesively bound or entrapped in the fibre matrix resulting in durable antimicrobial activity.

Antibacterial properties of silk fabric treated with silver nanoparticles

Silk is hygroscopic and is affected by microorganisms easily. Hence, treatment with antimicrobial agents can facilitate to make silk resistant to microbes. Silver nanoparticles have been attempted by researchers and applied as antimicrobial chemical finish on textiles. Silk has also been applied with silver nanoparticles through exhaust method to obtain antimicrobial properties. However, use of cross-linking agents such as 1,2,3,4 butane tetra carboxylic acid (BTCA) for entrapping silver nanoparticles in the interstitials of the silk molecular chain has not been attempted. The present study is focused on the application of BTCA on silk in the presence of sodium hypophosphite (SHP) simultaneously using silver nanoparticles has been done by pad-dry-cure (2dip/2nip) method. Application of 6% BTCA with 3% SHP and 250 ppm of silver nanoparticles gave satisfactory antimicrobial properties. Infrared spectroscopic (FTIR) studies showed good cross-linking of BTCA. X-ray diffraction studies depict that the crystal structure and crystallinity % of treated silk did not change due to the treatment. SEM studies showed the impregnation of silver nanoparticles on to the fibre matrix. Different physical properties of silk fabric did not change due to the treatment. Based on the studies, it is inferred that BTCA cross-links with silk fibroin at the carboxyl and amine groups, create a lattice void and trap silver nanoparticles giving durable antimicrobial finish.

High strength paper production based on esterification of thermomechanical pulp fibers in the presence of poly(vinyl alcohol).

Thermomechanical pulp (TMP) fibers, generally used to produce newspapers and carton materials, have poor inter- and intra-fiber bonding contributing to low strength properties. Poly(vinyl alcohol) (PVOH) was applied as a co-additive of 1,2,3,4-butanetetracarboxylic acid (BTCA), in the presence of sodium hypophosphite (SHP) as a catalyst, to esterify paper sheets based on TMP fibers. Fourier transform infrared (FTIR) spectroscopy technique was used to confirm the formation of the ester bond. The effects of curing temperature, molar mass and mass amount of the PVOH on the tensile index were investigated. The increasing of the curing temperature improved further the wet tensile index. The presence of PVOH increased both the dry and the wet tensile index of the paper sheets. The rise of both the molar mass and the mass amount of PVOH improved the tensile index.

A novel multifunctional cotton fabric using ZrO2 NPs/urea/CTAB/MA/SHP: introducing flame retardant, photoactive and antibacterial properties

This study was aimed to investigate the possibility of producing multifunctional properties on cotton fabric using ZrO2 nanoparticles along with cetyltrimethylammonium bromide (CTAB) and urea. Maleic acid was also used as a cross-linking agent in the presence of sodium hypophosphite as the catalyst to stabilize fabric from creasing and nanoparticles on the fabric surface. The flame retardant properties of the treated samples were examined using char length and thermogravimetry analysis. The self-cleaning properties of treated cotton fabrics were also analyzed based on the discoloration of methylene blue under sunlight irradiation. The antibacterial activities of treated fabrics were examined against Escherichia coli through counting method. The surface of the treated cotton and microstructure of nanoparticles were characterized by scanning electron microscopy and transmission electron microscopy. Introducing urea as a nitrogen source enhanced both the flame retardant and photoactivity of the nano-ZrO2-treated fabric. Moreover, incorporating CTAB in the finishing formulation exhibited the satisfactory antibacterial properties on the treated fabrics.

A New Class of Biobased Paper Dry Strength Agents: Synthesis and Characterization of Soy-Based Polymers

The goal of the current effort was to develop a new soy-based (soy flour) derivative to impart high fiber–fiber strength improvements to two-dimensional paper sheets. The success of the research hinged on successful proliferation of carboxylic and/or amine functionalities onto the polymeric backbone of the soy flour to significantly contribute to improved interfiber bonding of the paper–fiber sheets. Diethylenetriaminepentaacetic acid (DTPA) was reacted with soy flour in the presence of sodium hypophosphite and complexed with chitosan for the development of a new class of dry strength agents to improve integration into pulp fibers and thus increase interfiber bonding. The synthetic conditions including surface modifier concentration, time, temperature, pH, and material-to-liquor ratio were optimized. The paper materials incorporating the DTPA cross-linked (modified) soy flour agent demonstrated unprecedented tensile strength increases. A 1% soy protein flour–DTPA–-chitosan agent by mass of pulp-based slurry was thoroughly mixed before generating two-dimensional hand sheets whose tensile indices increased 52.6%, 53%, and 57.8% for recovered (OCC, old corrugated containerboard), NSSC (virgin) pulp, and kraft (virgin) pulp sheets, respectively. The modified soy flour agent-treated pulp sheets also provided significantly increased gloss and water repellency with diminished surface roughness.

A comparison between acrilic resin and butanetetracarboxylic acid used to bind TiO2 nanoparticles to cotton fabrics

In order to apply finishing particles onto fabrics, several methods such as, padding, bath exhaustion, spraying and foaming can be used. In this research, spray treatment is compared to padding when applying TiO2 nanoparticles onto textiles. Cotton fabric surfaces were observed by scanning electron microscopy and characterized by Fourier Transform Infrared spectroscopy and energy dispersive using X-ray (EDX). EDX technique showed that it was a suitable method to detect the presence of Ti particles on the fabric surface. We confirm that the fabric treated by padding contained procedure a higher quantity of Ti particles than the one treated by spraying. On the other hand, we compared two different auxiliary products to bind the particles onto the fibers, an acrylic resin and the polycarboxylic acid 1,2,3,4-butanetetracarboxylic acid (BTCA) in the presence of sodium hypophosphite. We used EDX to evaluate the effectiveness of both binders after washing. Compared with samples without a binder treatment, many more TiO2 particles were retained on the fibers with the acrylic resin after five washing cycles. When treated with BTCA, however, the results were comparable to the sample with no binder.