Antimony oxidation and adsorption by in-situ formed biogenic Mn oxide and Fe–Mn oxides

Antimony（Sb）, which can be toxic at relatively low concentrations, may co-exist with Mn（Ⅱ）and/or Fe（Ⅱ） in some groundwater and surface water bodies. Here we investigated the potential oxidation and adsorption pathways of Sb（Ⅲ and V） species in the presence of Mn（Ⅱ） and Mn-oxidizing bacteria, with or without Fe（Ⅱ）. Batch experiments were conducted to determine the oxidation and adsorption characteristics of Sb species in the presence of biogenic Mn oxides（BMOs）, which were formed in-situ via the oxidation of Mn（Ⅱ） by a Mn-oxidizing bacterium（Pseudomonas sp. QJX-1）. Results indicated that Sb（Ⅲ） ions could be oxidized to Sb（V） ions by BMO, but only Sb（V） originating from Sb（Ⅲ） oxidation was adsorbed effectively by BMO. Introduced Fe（Ⅱ） was chemically oxidized to Fe OOH, the precipitates of which mixed with BMO to form a new compound, biogenic Fe–Mn oxides（BFMO）. The BMO part of the BFMO mainly oxidized and the Fe OOH of the BFMO mainly adsorbed the Sb species. In aquatic solutions containing both As（Ⅲ） and Sb（Ⅲ）, the BFMO that formed in-situ preferentially oxidized Sb over As but adsorbed As more efficiently. Chemical analysis and reverse transcription real-time polymerase chain reaction revealed that the presence of Fe（Ⅱ）, As（Ⅲ） and Sb（Ⅲ） accelerated the oxidation of Mn（Ⅱ） but inhibited the activity of Mn-oxidizing bacteria. These results provide significant insights into the biogeochemical pathways of Sb, Mn（Ⅱ） in aquatic ecosystems, with or without Fe（Ⅱ）.

An Antimony Oxide pH Electrode for Tissue Culture Medium

A new approach named“caterpillar melt method”was developed to prepare wire type antimony oxide electrode for pH measurement in agar medium for tissue culture.A micro antimony wire was prepared from melt of the metal with the help of a glass capillary and the surface of the wire was oxidized in nitrate melt to obtain an antimony oxide electrode. Characterization results showed that the oxide layer is dense and uniform,with high physical and chemical stability.The electrode has a fast and stable response toward pH change for aqueous solutions.The potential of the antimony electrode has a linear relationship with the pH of the solution (R^2=1.00) with a sensitivity of 54.1mV/pH.The electrode works well and is more stable in agar medium during tissue culture for pH monitoring.

Antimony oxides-protected ultrathin Ir-Sb nanowires as bifunctional hydrogen electrocatalysts

Developing electrocatalysts with fast kinetics and long-term stability for alkaline hydrogen oxidation reaction(HOR)and hydrogen evolution reaction(HER)is of considerable importance for the industrial production of green and sustainable energy.Here,an ultrathin Ir-Sb nanowires(Ir-Sb NWs)protected by antimony oxides(SbO_(x))was synthesized as an efficient bifunctional catalyst for both HOR and HER under alkaline media.Except from the much higher mass activities of Ir-Sb nanowires than those of Ir nanowires(Ir NWs)and commercial Pt/C,the SbO_(x) protective layer also contributes to the maintenance of morphology and anti-CO poisoning ability,leading to the long-term cycling performance in the presence of CO.Specifically,the Ir-Sb NW/SbO_(x) exhibits the highest catalytic activities,which are about 3.5 and 4.8 times to those of Ir NW/C and commercial Pt/C toward HOR,respectively.This work provides that the ultrathin morphology and H_(2)O-occupied Sb sites can exert the intrinsic high activity of Ir and effectively optimize the absorption of OH*both in alkaline HER/HOR electrolysis.

Mixed iridium-nickel oxides supported on antimony-doped tin oxide as highly efficient and stable acidic oxygen evolution catalysts

Proton exchange membrane(PEM)water electrolysis represents a promising technology for green hydrogen production,but its widespread deployment is greatly hindered by the indispensable usage of platinum group metal catalysts,especially iridium(Ir)based materials for the energy-demanding oxygen evolution reaction(OER).Herein,we report a new sequential precipitation approach to the synthesis of mixed Ir-nickel(Ni)oxy-hydroxide supported on antimony-doped tin oxide(ATO)nanoparticles(IrNiyO_(x)/ATO,20 wt.%(Ir+Ni),y=0,1,2,and 3),aiming to reduce the utilisation of scarce and precious Ir while maintaining its good acidic OER performance.When tested in strongly acidic electrolyte(0.1 M HClO_(4)),the optimised IrNi1Ox/ATO shows a mass activity of 1.0 mAµgIr^(−1) and a large turnover frequency of 123 s^(−1) at an overpotential of 350 mV,as well as a comparatively small Tafel slope of 50 mV dec^(−1),better than the IrOx/ATO control,particularly with a markedly reduced Ir loading of only 19.7µgIr cm^(−2).Importantly,IrNi1O_(x)/ATO also exhibits substantially better catalytic stability than other reference catalysts,able to continuously catalyse acidic OER at 10 mA cm^(−2) for 15 h without obvious degradation.Our in-situ synchrotron-based x-ray absorption spectroscopy confirmed that the Ir^(3+)/Ir^(4+)species are the active sites for the acidic OER.Furthermore,the performance of IrNi1Ox/ATO was also preliminarily evaluated in a membrane electrode assembly,which shows better activity and stability than other reference catalysts.The IrNi1Ox/ATO reported in this work is a promising alternative to commercial IrO_(2) based catalysts for PEM electrolysis.

Electrical and Mechanical Properties of PMMA/nano-ATO Composites

Conducting nanocomposites of poly （methyl methacrylate） （PMMA） and antimony doped tin oxide （ATO） were prepared by solution blending. The influences of ATO content on the electrical conductivity, thermal stability, and mechanical properties of the nanocomposites were investigated. A homogeneous dispersion of silane coupling agent modified ATO was achieved in PMMA matrix as evidenced by scanning electron microscopy. The resultant PMMA/silane-ATO nanocomposites were electrically conductive with significant conductivity enhancement at 4 wt pct. It was found that the composition at 4 wt pct ATO gave the higher tensile strength. Furthermore, it gave the largest elongation at break value among all the compositions. Thermal stability of the nanocomposites was remarkably enhanced by the incorporation of silane-ATO.

Comprehensive Optimization of Electrical and Optical Properties for ATO Films Prepared by Pulsed Laser Deposition

Antimony doped tin oxide（ATO） thin films have been prepared by pulsed laser deposition（PLD） method.The intrinsic effect of Sb dopant,including the Sb content,transition degree between Sb（3＋） and Sb（5＋） and crystallinity on the electrical and optical properties of the ATO thin films is mainly investigated.It is suggested that the transition degree of Sb（3＋） towards Sb（5＋）（Sb（5＋）/Sb（3＋） ratio） is determined by Sb content.When the Sb content is increased to 12 at%,the Sb（5＋）/Sb（3＋） ratio reaches the highest value of 2.05,corresponding to the resistivity of 2.70×10（-3） Ω·cm.Meanwhile,the Burstein-Moss effect caused by the increase of carrier concentration is observed and the band gap of the ATO thin films is broadened to 4.0 eV when the Sb content is increased to 12 at%,corresponding to the highest average optical transmittance of 92%.Comprehensively considering the combination of electrical and optical properties,the ATO thin films deposited with Sb content of 12 at%exhibit the best properties with the highest ＂figure of merit＂ of 3.85×10（-3） Ω（-1）.Finally,an antimony selenide（Sb_2Se_3） heterojunction solar cell prototype with the ATO thin film as the anode has been prepared,and a power conversion efficiency of 0.83%has been achieved.

Effect of Alloying Elements(Sb,B) on Recrystallization and Oxidation of Mn-Containing IF Steel

The effects of minor alloying elements（antimony,boron） on the recrystallization and oxidation of Mn-containing interstitial free（IF） steels were investigated using confocal scanning laser microscope（CSLM） under controlled atmosphere of 95% Ar and 5% H2（volume percent） at different temperatures.The results indicated that oxidation and recrystallization were primarily controlled by the grain boundaries,which moved due to release of the stored energy or acted as the fast path diffusion of alloying elements.It was found that the addition of antimony suppressed both surface oxidation and internal oxidation,whereas boron addition accelerated surface oxidation but decreased internal oxidation.The reasons caused were that the alloying elements of antimony or boron were known to segregate on the surfaces or grain boundaries to occupy the surface adsorption sites,which were expected to be less catalytic than bare iron on the transportation of alloying elements.The recrystallization was also retarded through adding minor antimony and boron elements.The oxidation kinetics of formation of grain boundary oxides were studied through calculating the areas along grain boundaries,and it was found that the areas parabolically increased with increasing time.

Improvement of the activity and SO_(2) tolerance of Sb-modified Mn/PG catalysts for NH_(3)-SCR at a low temperature

A series of MnM/palygorskite(PG)(M=La,W,Mo,Sb,Mg)catalysts was prepared by the wetness co-impregnation method for low-temperature selective catalytic reduction(SCR)of NO with NH_3.Conversion efficiency followed the order Sb>Mo>La>W>Mg.A combination of various physico-chemical techniques was used to investigate the influence of Sb-modified Mn/PG catalysts.MnSb_(0.156)/PG catalyst showed highest NO conversion at low temperatures in the presence of SO_(2) which reveals that addition of Sb oxides effectively enhances the SCR activity of catalysts.A SO_(2) step-wise study showed that MnSb_(0.156)/PG catalyst displays higher durable resistance to SO_(2) than Mn/PG catalyst,where the sulfating of active phase is greatly inhibited after Sb doping.Scanning electron microscopy and X-ray diffraction results showed that Sb loading enhances the dispersion of Mn oxides on the carrier surface.According to the results of characterization analyses,it is suggested that the main reason for the deactivation of Mn/PG is the formation of manganese sulfates which cause the permanent deactivation of Mn-based catalysts.For Sb-doped Mn/PG catalyst,SO_(x) ad-species formed were mainly combined with SbO_(x) rather than MnO_(x).This preferential interaction between SbO_(x) and SO_(2) effectively shields the MnO_(x) as active species from being sulfated by SO_(2) resulting in the improvement of SO_(2) tolerance on Sb-added catalyst.Multiple information support that,owing to the addition of Sb,original formed MnO_(x) crystallite has been completely transformed into highly dispersed amorphous phase accounting for higher SCR activity.

Precise tuning of low-crystalline Sb@Sb_(2)O_(3) confined in 3D porous carbon network for fast and stable potassium ion storage

Metal antimony(Sb)is a promising anode material of potassium-ion batteries(PIBs)for its high theoretical capacity but limited by its inferior cycle stability due to the serious volume expansion during cycling.Herein,we design and construct a kind of low-crystalline Sb nanoparticles coated with amorphous Sb2O3 and dispersed into three-dimensional porous carbon via a strategy involving NaCl template-assisted insitu pyrolysis and subsequent low-temperature heat-treated in air.Significantly,the crystallinity and ratio of Sb/Sb_(2)O_(3) have been precisely tuned and controlled,and the optimized sample of HTSb@Sb_(2)O_(3)@C-4 displays a high reversible specific capacity of 543.9 m Ah g^(-1) at 0.1 A g^(-1),superior rate capability and excellent cycle stability(~273 m Ah g^(-1) at 2 A g^(-1) after 2000 cycles)as an anode of PIBs.The outstanding potassium-ion storage performance can be ascribed to the appropriate crystallinity and the multiplebuffer-matrix structure comprising an interconnected porous conductive carbon to relieve the volume changes and suppress the aggregation of Sb,a Sb nanoparticle core to shorten the ion transport pathways and decrease the mechanical stress,and a low-crystalline Sb_(2)O_(3) as the shell to consolidate the interface between Sb and carbon as well as facilitate the rapid electron transport.The dynamic analysis shows that the composite is mainly controlled by pseudocapacitance mechanism.This work provides a novel thought to design high-performance composite electrode in energy storage devices.

Preparation and Degradation Phenol Characterization of Ti/SnO_2-Sb-Mo Electrode Doped with Different Contents of Molybdenum

The Ti/SnO2-Sb-Mo electrodes doped with different molar ratios of molybdenum（Mo） were prepared by sol—gel method in order to investigate the effect of Mo on the characterization of Ti/SnO2-Sb—Mo electrodes.X-ray diffraction（XRD）,field-emission scanning electron microscopy（FE-SEM）,energy dispersive spectrometry（EDS）,and linear scanning voltammetry（LSV） were used to scrutinize the coating material and the electrochemical activity.The concentration of phenol,the value of total organic carbon（TOC）,the mineralization current efficiency（MCE） and the ultraviolet—visible spectroscopy（UV-Vis） spectrum of phenol solution were measured over the electrochemical degradation process of phenol to confirm the phenol degradation characterization of Ti/SnO2-Sb-Mo electrodes.Results showed that the electrode at the Mo content of 1 at.%provided optimal catalytic activity for phenol degradation and the longest life time.The removal percentage of phenol and TOC were 99.62%and82.67%,respectively.The Ti/SnO2-Sb-Mo electrode with 1 at.%of Mo reached maximum MCE of phenol oxidation.The kinetic investigation of phenol and TOC degradation displayed the pseudo-first order reaction model.The Ti/SnO2-Sb-Mo electrode coating with 7 at.%Mo presented the highest oxygen evolution overpotential,indicating the diverse effects for different Mo molar ratio doping.

High-performance Sb:SnO_2 Compact Thin Film Based on Surfactant-free and Binder-free Sb:Sn_3O_4 Suspension

Surfactant-free and binder-free antimony-doped tin oxide （ATO） transparent conducting thin films were fabricated through spin coating and rapid annealing processes, in which nanosheets were assembled into a compact structure via self-contracting high pressure. The mechanism of this compact thin film for- mation was further proposed and analyzed. The compact ATO thin film had a low root mean square （RMS） roughness of 5.03 nm. This surfactant-free and binder-free compact ATO thin film delivered low resistivity of 3.04 × 10^-2 Ω cm, stable resistivity which only increased 13% after exposing in 65% RH air for half a month, high transmittance of 92.70% at 550 nm, and high band gap energy of 4.07 eV. This effective strategy will provide new insight into the synthesis of low-cost and high-performance compact thin films.

Improving the Catalytic Efficiency of NiFe-LDH/ATO by Air Plasma Treatment for Oxygen Evolution Reaction

Developing efficient catalysts toward the oxygen evolution reaction(OER)is important for water splitting and rechargeable metal-air batteries.Although NiFe oxides are considered as potentially applicable catalysts in the alkaline media,there are still a limited numbers of researches working on membrane electrode assembly(MEA)fed with pure water due to their poor electrical conductivity.In this work,antimony doped tin oxide(ATO)has been employed as conductive supports where NiFe layered double hydroxide uniformly dispersed[named NiFe-LDH(layered double hydroxide)/ATO].The catalysts have been synthesized by a one-step co-precipitation method,and then NiFe-LDH/ATO-air plasma was obtained through mild air plasma treatment.According to XPS analysis,binding energies of Ni2p and Fe2p were shifted negatively.Moreover,a new signal of low oxygen coordination appeared on O1s spectrum after air plasma treatment.These XPS results indicated that oxygen vacancies(Ov)were generated after air plasma treatment.Electrochemical measurement indicated that the vacancy-rich NiFe-LDH/ATO-air plasma exhibited better performance than NiFe-LDH/ATO not only in 1 mol/L KOH solutions but also in an alkaline polymer electrolyte water electrolyzer(APEWE)fed with deionized water.This work provides a feasible way to design practical catalysts used in electrochemical energy conversion systems by choosing corrosion resistance supports and defect engineering.