In this work, an efficient AgVO3/MoS 2 composite photocatalyst was successfully synthesized via a hydrothermal method. The photocatalytic activity of the as-prepared photocatalyst was evaluated by using it for assessi...In this work, an efficient AgVO3/MoS 2 composite photocatalyst was successfully synthesized via a hydrothermal method. The photocatalytic activity of the as-prepared photocatalyst was evaluated by using it for assessing the degradation of different organic pollutants under visible-light irradiation. The composite 3%-AgVO3/MoS 2 catalyst demonstrated a significantly enhanced photocatalytic activity compared to the pure compounds（AgVO3 and MoS2）. The reason behind the excellent photocatalytic performance was the modification of MoS 2 by AgVO3 to facilitate O2 adsorption/activation. In addition, the composite catalyst facilitates the two-electron oxygen reduction reaction whereby H2O2 is generated on the surface of MoS 2 to produce additional reactive oxygen species（ROSs）. ESR coupled with the POPHA fluorescence detection method and a free radical capture experiment were used to elucidate the mechanism of formation of the ROSs, including ·OH, ·O2- and H2O2. Furthermore, the generation of additional ROSs could accelerate electron consumption, leaving behind more holes for the oxidation of organic pollutants. A possible photocatalytic mechanism of the composite is also discussed.展开更多
NiCr/AgVO3 self-lubricating composite was prepared by powder cold-pressed method with the NiCr alloy as the matrix and 10 wt.% additive of AgVO3 as solid lubricant. The AgVO3 additive powder was synthesized by the pre...NiCr/AgVO3 self-lubricating composite was prepared by powder cold-pressed method with the NiCr alloy as the matrix and 10 wt.% additive of AgVO3 as solid lubricant. The AgVO3 additive powder was synthesized by the precipitation method which exhibits a melting point of 460℃. Microstructure, phase composition and thermal properties of the AgVO3 powder, as well as the composite of NiCr/AgVO3 were analyzed using scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and differential scanning calorimeter （DSC）. The friction and wear behavior of the specimens from room temperature （R.T.） to 800℃ was evaluated using a ball-on-disk tribometer and 3D white light interference （WLI）. The results showed that the friction coefficient of this material under atmosphere decreases with temperature increasing from R.T. to 800 ~C. However, the wear rate firstly increases from R.T. to 200℃, almost remains stable from 200℃ to 600℃, and then decreases with further increasing the temperature up to 800 ℃. It is also found that the prepared composite materials show a better frictional behavior than NiCr alloy over the whole range of temperatures, which is mainly attributed to solid lubrication of AgVO3 exhibiting a lamella-slip structure at temperatures below 460℃ and forms liquid-film at elevated temperatures above the melting point.展开更多
基金supported by the National Natural Science Foundation of China(21706104)the Natural Science Foundation of Jiangsu Province(BK20150484)+1 种基金the China Postdoctoral Science Foundation(2015M570416)the financial support of the Research Foundation of Jiangsu University,China(14JDG148)~~
文摘In this work, an efficient AgVO3/MoS 2 composite photocatalyst was successfully synthesized via a hydrothermal method. The photocatalytic activity of the as-prepared photocatalyst was evaluated by using it for assessing the degradation of different organic pollutants under visible-light irradiation. The composite 3%-AgVO3/MoS 2 catalyst demonstrated a significantly enhanced photocatalytic activity compared to the pure compounds（AgVO3 and MoS2）. The reason behind the excellent photocatalytic performance was the modification of MoS 2 by AgVO3 to facilitate O2 adsorption/activation. In addition, the composite catalyst facilitates the two-electron oxygen reduction reaction whereby H2O2 is generated on the surface of MoS 2 to produce additional reactive oxygen species（ROSs）. ESR coupled with the POPHA fluorescence detection method and a free radical capture experiment were used to elucidate the mechanism of formation of the ROSs, including ·OH, ·O2- and H2O2. Furthermore, the generation of additional ROSs could accelerate electron consumption, leaving behind more holes for the oxidation of organic pollutants. A possible photocatalytic mechanism of the composite is also discussed.
基金supported by the National Natural Science Foundation of China(Nos.50901071 and 51001093)the Natural Science Foundation of Jiangsu Province,China(No.BK2011452)
文摘NiCr/AgVO3 self-lubricating composite was prepared by powder cold-pressed method with the NiCr alloy as the matrix and 10 wt.% additive of AgVO3 as solid lubricant. The AgVO3 additive powder was synthesized by the precipitation method which exhibits a melting point of 460℃. Microstructure, phase composition and thermal properties of the AgVO3 powder, as well as the composite of NiCr/AgVO3 were analyzed using scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and differential scanning calorimeter （DSC）. The friction and wear behavior of the specimens from room temperature （R.T.） to 800℃ was evaluated using a ball-on-disk tribometer and 3D white light interference （WLI）. The results showed that the friction coefficient of this material under atmosphere decreases with temperature increasing from R.T. to 800 ~C. However, the wear rate firstly increases from R.T. to 200℃, almost remains stable from 200℃ to 600℃, and then decreases with further increasing the temperature up to 800 ℃. It is also found that the prepared composite materials show a better frictional behavior than NiCr alloy over the whole range of temperatures, which is mainly attributed to solid lubrication of AgVO3 exhibiting a lamella-slip structure at temperatures below 460℃ and forms liquid-film at elevated temperatures above the melting point.
