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Cellulose fibers have been one of the most common fibers due to their biodegradability, excellent mechanical properties, biocompatibility, high absorption ability, cheapness and renewability. In this study, novel, simple and green method is concerned with the production of multifunctional cellulose nanofibers (CNFs). Nanocomposites consisting of silver nanoparticles (AgNPs) and polyaniline (PANi) were in situ synthesized into plasma-pretreated cellulosic nanofibers fabricated by solution blowing spinning technique. The produced cellulose acetate nanofibers were then subjected to deacetylation followed by plasma-activation followed by a treatment with aniline and silver nitrate (AgNO3) in the presence of ammonium acetate. Plasma-assisted oxidation polymerization process of aniline into PANi associated with a reduction of Ag+ into AgNPs results in their permanent insolubility into the surface of the cellulose nanofibers. The morphologies and elemental contents were determined by polarizing optical microscope (POM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray patterns and scanning electron microscopy (SEM). Additionally, transmission electron microscope (TEM) was applied to explore the morphologies of silver nanoparticles and PANi showing particle diameter between 12 and 25 nm. The antimicrobial Ag NPs were formed from an aqueous medium of silver nitrate by taking the reduction ability advantage of the electrically active PANi. The immobilization of polyaniline and silver nanoparticles into the surface of the cellulose nanofibers enhanced its electrical conductivity. The produced CNFs demonstrated a high UV protection as well as antibacterial activity.

The amount of hydrogen gas generated from metal oxide materials, based on a thermochemical water-splitting method, gradually reduces as the surface of the metal oxide oxidizes during the hydrogen generation process. To regenerate hydrogen, the oxygen reduction process of a metal oxide at high temperatures (1000–2500 °C) is generally required. In this study, to overcome the problem of an energy efficiency imbalance, in which the required energy of the oxygen reduction process for hydrogen regeneration is higher than the generated hydrogen energy, we investigated the possibility of the oxygen reduction of a metal oxide with a low energy using microwave irradiation. For this purpose, a macroporous nickel-oxide structure was used as a metal oxide catalyst to generate hydrogen gas, and the oxidized surface of the macroporous nickel-oxide structure could be reduced by microwave irradiation. Through this oxidation reduction process, ∼750 μmol g−1 of hydrogen gas could be continuously regenerated. In this way, it is expected that oxygen-enriched metal oxide materials can be efficiently reduced by microwave irradiation, with a low power consumption of

In this article, we propose a simple redox process to in-situ create a cellular architecture on Ni solid sheet by the direct oxidization (O 2 ) and subsequent reduction (H 2 ) at 750 °C. Nanocrystalline Ni(OH) 2 is fabricated on the micro-porous Ni sheet (MPNS) using cathodic electrodeposition method to form a MPNS-Ni(OH) 2 electrode for supercapacitor. The obtained results indicate that the created micro-porous architectures expand the contact interfaces between the Ni(OH) 2 and Ni substrate and enhance its supercapacitor performance and cyclic stability.

A low-temperature oxidation-reduction process was used to modify the surface of a Cu current collector (foil) for a Si film electrode. The surfaces of the modified Cu foils were investigated under various oxidation-reduction conditions, and the electrochemical properties of Si film electrodes containing the surface modified foils were evaluated. Various nanostructures were found to have formed on the surface; for example, Cu(OH)2 needles, CuO flowers, and CuO plates formed on Cu-foil surfaces oxidized at 313 K for 1, 10, and 30 min, respectively. Furthermore, these nanostructures were transformed to coral-like Cu2O structures after reduction at 673 K. The amount of Cu2O and the surface roughness decreased on increasing reduction time. The Si film electrode containing a Cu foil reduced for 6 h showed the best electrochemical performance (83.5% of the initial efficiency and 74.8% of capacity retention) due to the small amount of Cu2O and the formation of coral-like structures.

Wet desulfurization and denitrification technologies are one of the main research directions in the future air pollution control. Compared with the traditional macro-bubbles, the MNBs can spontaneously generate  · O H with high oxidizing ability, and also improve the gas solubility. Na2SO3 is a strong reducing agent and can react with NO, NO2, NO2– and NO3– to convert ionic N to non-toxic and harmless N2. In the study, based on the principle of wet desulfurization and denitrification, a new recycling oxidation–reduction process was firstly proposed for simultaneous removal of NO and SO2 by using the MNBGLS which was generated with a MNBG through recycling Na2SO3 aqueous solution at a given concentration from a column reactor and the simulated flue gas composed of NO, SO2, N2 and/or other gases such as O2 and CO2. The MNBGLS was recycled continuously from the MNBG to the reactor. The effects of various experimental parameters, such as operation time, initial pH and temperature of absorbent, Na2SO3 concentration, NO concentration, SO2 concentration, the presence of O2 and CO2, on the removal of NO and SO2, were investigated. All the investigated parameters affected the removal of NO, whereas only initial solution pH influenced the removal of SO2. This new process can not only achieve high NO and SO2 removal efficiencies but also treat NO2– and NO3– so as to reduce the cost of subsequent wastewater treatment. Moreover, the main removal product, SO42−, can be recycled. Thus it is an economical, environmentally friendly and efficient desulfurization and denitrification process.

In the process of hot dip galvanizing high tensile strength sheet steels containing Si and Mn, selective surface oxidation of Si and Mn causes coating defects. One promising method for overcoming this problem is an oxidation-reduction process. When the steel surface is exposed to an oxidizing atmosphere, it will react primarily by forming an Fe oxide, which can be reduced by hydrogen in a reduction process that follows. It has been explained that good wettability can be obtained due to the formation of pure iron. However, the mechanism of suppression of selective surface oxidation has not been clearly understood in detail yet. In order to reveal this mechanism, the present study focused on both Mn and Fe oxidation behavior during the oxidation-reduction process for a cold-rolled sheet steel containing 0.25mass%Si-1.8mass%Mn. Surface and cross-sectional analyses were performed by using secondary electron microscopy and transmission electron microscopy. Selective surface oxidation behavior was investigated by glow discharge optical emission spectroscopy. The main results obtained are as follows. First, selective surface oxidation of Mn was suppressed even if soaking was continued after completion of the reduction of the Fe oxide. Second, as the reduction process proceeded, Mn was trapped as an internal oxide under the Fe oxide layer. Moreover, depletion of solute Mn was observed in the matrix. From these results, depletion of solute Mn is supposed to suppress the outer diffusion of Mn during soaking. Therefore, selective surface oxidation of Mn is suppressed even after Fe oxide reduction is completed.

An improved Cu-Cu joint strength was achieved by a pressureless sintering bonding using microscale Cu particles with an oxidation-reduction process for power device packaging. After the bonding at 300 °C in air, Cu2O nanoparticles uniformly formed on the surface of microscale Cu particles through a thermal oxidation, and the formation of neck between microscale Cu particles was obvious. Then, after the following bonding at 300 °C in a reductive formic acid atmosphere, the Cu2O nanoparticle surface of microscale Cu particles was reduced to a Cu nanostructured surface, meanwhile the joining between the microscale Cu particles was facilitated by formed nanostructured surface, resulting a higher joint strength than that of the bonding joint with entire formic acid atmosphere process. The results demonstrate that the pressureless sintering bonding using microscale Cu particles by the oxidation-reduction process has the potential to fulfill the requirement of die-attach bonding for power device packaging.

Aligned multi-walled carbon nanotubes (MWCNTs) were synthesized directly on a stainless steel surface by surface activation by intense oxidation in air followed by a moderate reduction in H 2 without any wet process. This method is extremely simple compared with conventional ways that need catalyst loading steps or acid pre-etching steps to synthesize carbon nanotubes on stainless steel surfaces. It was found that the length of MWCNT bundles could reach 80 μm when the oxidation step was properly controlled. It was demonstrated that MWCNTs synthesized on stainless steel meshes could be used as a catalyst support to enhance ozone oxidation in the decomposition of phenol in water.

The unusual wetting phenomenon of liquid Bi on surface-porous copper has been studied. A porous layer was prepared at the surface of a copper substrate and the wetting behavior of liquid Bi on this layer was investigated and compared with that on a flat solid copper substrate. A surface-oxidized copper substrate was reduced at 473 K in H2 to prepare a porous layer at the surface. Since the contact angle of liquid Bi on the flat solid copper substrate was gradually declining with increasing temperature, the behavior of liquid Bi on solid copper was shown to have good-wettability. In addition, the unusual wetting behavior of liquid Bi was observed on surface-porous copper substrate. This result is evidence that the pores in the porous layer are 3-dimensionally inter-connected. This usual wetting phenomenon of liquid Bi was then applied in the joining of copper wire with the surface-porous copper substrate. Bonding was successfully achieved with a minimized weld overlay at the joining point. [doi:10.2320/matertrans.MRA2007179]

Voltametrically stable 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS2−) modified electrode was obtained by sol–gel processing of methyltrimethoxysilane based sol with dissolved ABTS2− together with dispersed graphite particles. Next, extracellular laccase from Cerrena unicolor was encapsulated within a thin hydrophilic tetramethoxysilane film on the top the electrode. The obtained ABTS2− modified carbon ceramic electrode exhibits stable voltammetry corresponding to the surface confined oxidation reduction process. The biocatalytic activity of this electrode is similar to that observed when ABTS2− is present in solution. Keywords: Laccase, ABTS, Dioxygen reduction, Sol–gel, Carbon ceramic electrode, Bioelectrocatalysis

Unusual wetting behavior of liquid Cu was found on a surface-oxidized iron substrate in reducing atmosphere. Liquid Cu wetted and spread very widely on the iron substrate when a droplet was attached with the substrate in Ar-10%H2 after the surface oxidation of the substrate. The oxidationreduction process fabricates a porous layer at the surface of the iron substrate. The pores in the porous iron layer are 3-dimensionally interconnected. Thus, liquid metals, which are contacted with the reduced iron samples, penetrate into these pores by capillary force to cause the unusual wetting behavior. It has been already confirmed that liquid Ag, Sn, In and Bi show this phenomenon onto surface-porous iron samples as well as liquid Cu. This unusual wetting behavior of a liquid metal has been correlated to the normal contact angle of the liquid metal on a flat iron substrate.

An alternate energy storage device for high power applications are supercapacitors. They store energy either by pure electrostatic charge accumulation in the electrochemical double layer or as pseudo capacitance from fast reversible oxidation reduction process. However, they have low energy density. The electrodes in the Electrochemical Double Layer Capacitors (EDLC) are made of high surface area carbon. The carbon that can be used range from activated carbon to Graphene, with varying particle size, surface area, pore size and pore distribution. The main emphasis in the development of EDLCs is fabrication of electrodes having high surface area which would enhance the storage density of the EDLC. The EDLCs are assembled with different electrolytes which determine the operational voltage. Solid electrolytes can also be used as electrolyte and have an advantage in that we can avoid electrolyte leaks and are easy to handle. This would improve the reliability. They can also be shaped and sized to suit the application. The perflurosulfonic acid polymer as electrolyte has been used by various groups for EDLC application. The perflurosulfonic acid polymer possesses high ionic conductivity, good thermal stability, adequate mechanical strength and excellent chemical stability. The EDLCs, which are based on high-surface area carbon materials, utilize the capacitance arising from a purely non-Faradaic charge separation at an electrode/electrolyte interface. Carbon is widely used for many practical applications, especially for the adsorption of ions and molecules, as catalyst supports and electrode materials. The chemical characteristics of carbon determine the performance in all these applications. It is now possible to synthesize one-, two-, or three-dimensional (1-, 2-, or 3-D) carbons. Thus, carbon materials are very suitable candidates for super capacitor electrodes. We can overcome some of the problems in activated carbon like varying micro or meso pores, poor ion mobility due to varying pore distribution, low electrical conductivity, by using Graphene. Many forms of Graphene have been used by various groups. Graphene nanoplates (GNP), with narrow mesopore distribution have been effectively used to enhance charge storage performance. It has been found that graphene shows smaller decrease in storage capacity with increasing scan rate.