Exploiting efficient and low-cost cocatalyst with a facile grafting strategy is of critical importance for significantly boosting the photocatalytic H2-evolution activity.In this study,S2^--adsorbed MoSx nanoparticle ...Exploiting efficient and low-cost cocatalyst with a facile grafting strategy is of critical importance for significantly boosting the photocatalytic H2-evolution activity.In this study,S2^--adsorbed MoSx nanoparticle as a superior H2-evolutoin cocatalyst was successfully grafted on the TiO2 surface to greatly boost its photocatalytic activity via one-step lactic acid-induced synthesis strategy.Herein,the lactic acid can induce the homogeneous production of amorphous MoSx(a-MoSx)nanoparticles from MoS42-precursor,while the symbiotic S2^-ions can be easily and availably self-adsorbed on the a-Mo Sxsurface,resulting in the formation of S2^--adsorbed a-Mo Sxnanoparticles with a small size of 0.5-3 nm.Photocatalytic results manifested that the S2^--adsorbed Mo Sxnanoparticles could dramatically facilitate the H2-generation rate of TiO2 photocatalysts(3452μmol h^-1 g^-1,AQE=16.5%).In situ irradiated XPS in conjunction with transient-state PL and photoelectrochemical tests reveal that the improved H_(2)-generation activity can be ascribed to the synergistic effect of boosted interfacial charge transfer from TiO_(2) to S^(2-)adsorbed Mo Sx and the superior H_(2)-evolution reaction on self-adsorbed S_(2-)ions.In addition,the S^(2-)-adsorbed Mo Sx nanoparticles can also act as the general H_(2)-generation cocatalyst to obviously promote the activity of other typical host photocatalysts such as g-C_(3) N_(4) and Cd S.This work provides an innovative approach to develop high-efficiency Mo Sx-based cocatalyst with boosted interfacial charge transfer toward highly efficient photocatalytic materials.展开更多
Molybdenum disulfide (MoS_2) has been applied to various space mechanisms as solid lubricant. The tribological characteristics of sputtered MoSx films have been improved by inert gas ion implantation. We tried to exte...Molybdenum disulfide (MoS_2) has been applied to various space mechanisms as solid lubricant. The tribological characteristics of sputtered MoSx films have been improved by inert gas ion implantation. We tried to extend the wear life and reduce friction coefficient by high energy implantation of indium ions. In friction tests, a pin-on-disk tester was used to measure friction coeffi- cient and wear life in a vacuum, dry air and air of 30%, 50% and 80% RH. Indium ions implanted the film at a dose of 1×10^(16) ions/cm^2 exhibited friction coefficient of 0.008 and 5.0 times longer wear life than the unimplanted ones did. However, the wear life of this film tested in high humid air presented no im- provement.展开更多
MoSx coatings were prepared by bipolar-pulse DC unbalanced magnetron-sputtering system with the variation of coating thickness at different Ar pressures. The composition and surface morphology were determined by using...MoSx coatings were prepared by bipolar-pulse DC unbalanced magnetron-sputtering system with the variation of coating thickness at different Ar pressures. The composition and surface morphology were determined by using energy dispersive X-ray and scanning electron microscopy; the structural characterisation was analyzed by X-ray diffraction. The friction and wear properties were investigated by fretting tests in air with less than 10% and 50% relative humidity. At 0.40 Pa pressure, (002) basal plane orientation was formed throughout the coatings. At 0.88 Pa and 1.60 Pa pressures, (002) basal plane orientation was only noticed in the first stage of coating growth (around 0.20祄 in thickness), and then edge orientations with their basal planes perpendicular to the surface would be evolved in the coatings. Humidity has a minor influence on the coatings that have (002) basal plane orientation, whereas the tribological properties of MoSx coatings with edge orientations are greatly affected by humidity. The mechanisms of coating growth and friction and wear processes are discussed.展开更多
MoS coatings were prepared by means of bipolar-pulsed DC magnetron sputtering on different substrate type at various temperature. The structure and fretting behavior of MoS, coatings have been determined respectively ...MoS coatings were prepared by means of bipolar-pulsed DC magnetron sputtering on different substrate type at various temperature. The structure and fretting behavior of MoS, coatings have been determined respectively by XRD and fretting tester in air of 10% to 90% RH and under the load of 1 to 10 N. With increasing substrate temperature, the edge orientation evolves in the MoSx coating, and the relative content of edge-to-basal orientation becomes large. The tribological performance of coatings gets deteriorated. Compared with MoS, coatings on TiN/H13, CrN/H13 and MoS /Ti multilayer, MoS coating on H13 substrate has a lower load bearing capacity, and worn away easily under higher normal load 5N or ION and in air of 90% RH during the fretting process. The friction and wear properties of MoS, coatings on TiN/H13 and CrN/H13 (dual-layer) are slight better than that of MoS, /Ti multilayer under the normal load tested and in air of<10%to90%RH.展开更多
MoSx (x = 1.79 ￣ 2.34) films of 200 nm thickness are deposited onto brass and C20 steel substrates by the ion beam assisted technique, respectively. Structures and compositions of these films, and changes in valence ...MoSx (x = 1.79 ￣ 2.34) films of 200 nm thickness are deposited onto brass and C20 steel substrates by the ion beam assisted technique, respectively. Structures and compositions of these films, and changes in valence states of the Mo element are examined by XRD and XPS before and after wear. The lubrication properties and wear resistances for two kinds of samples are evaluated using a pin-on-disk installation in atmosphere at the room temperature. Tribo-wear behaviours and the microstructures between two kinds of samples exhibit obvious differences.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51872221 and 21771142)the Fundamental Research Funds for the Central Universities(No.WUT 2019IB002)。
文摘Exploiting efficient and low-cost cocatalyst with a facile grafting strategy is of critical importance for significantly boosting the photocatalytic H2-evolution activity.In this study,S2^--adsorbed MoSx nanoparticle as a superior H2-evolutoin cocatalyst was successfully grafted on the TiO2 surface to greatly boost its photocatalytic activity via one-step lactic acid-induced synthesis strategy.Herein,the lactic acid can induce the homogeneous production of amorphous MoSx(a-MoSx)nanoparticles from MoS42-precursor,while the symbiotic S2^-ions can be easily and availably self-adsorbed on the a-Mo Sxsurface,resulting in the formation of S2^--adsorbed a-Mo Sxnanoparticles with a small size of 0.5-3 nm.Photocatalytic results manifested that the S2^--adsorbed Mo Sxnanoparticles could dramatically facilitate the H2-generation rate of TiO2 photocatalysts(3452μmol h^-1 g^-1,AQE=16.5%).In situ irradiated XPS in conjunction with transient-state PL and photoelectrochemical tests reveal that the improved H_(2)-generation activity can be ascribed to the synergistic effect of boosted interfacial charge transfer from TiO_(2) to S^(2-)adsorbed Mo Sx and the superior H_(2)-evolution reaction on self-adsorbed S_(2-)ions.In addition,the S^(2-)-adsorbed Mo Sx nanoparticles can also act as the general H_(2)-generation cocatalyst to obviously promote the activity of other typical host photocatalysts such as g-C_(3) N_(4) and Cd S.This work provides an innovative approach to develop high-efficiency Mo Sx-based cocatalyst with boosted interfacial charge transfer toward highly efficient photocatalytic materials.
文摘Molybdenum disulfide (MoS_2) has been applied to various space mechanisms as solid lubricant. The tribological characteristics of sputtered MoSx films have been improved by inert gas ion implantation. We tried to extend the wear life and reduce friction coefficient by high energy implantation of indium ions. In friction tests, a pin-on-disk tester was used to measure friction coeffi- cient and wear life in a vacuum, dry air and air of 30%, 50% and 80% RH. Indium ions implanted the film at a dose of 1×10^(16) ions/cm^2 exhibited friction coefficient of 0.008 and 5.0 times longer wear life than the unimplanted ones did. However, the wear life of this film tested in high humid air presented no im- provement.
基金This research is a part of an Eureka project funded by the Flemish government (Lubrimat 960235), a Belgium-China interna-tional scientific and technological co-operation project supported by the Flemish government and the China government (project BIL 96
文摘MoSx coatings were prepared by bipolar-pulse DC unbalanced magnetron-sputtering system with the variation of coating thickness at different Ar pressures. The composition and surface morphology were determined by using energy dispersive X-ray and scanning electron microscopy; the structural characterisation was analyzed by X-ray diffraction. The friction and wear properties were investigated by fretting tests in air with less than 10% and 50% relative humidity. At 0.40 Pa pressure, (002) basal plane orientation was formed throughout the coatings. At 0.88 Pa and 1.60 Pa pressures, (002) basal plane orientation was only noticed in the first stage of coating growth (around 0.20祄 in thickness), and then edge orientations with their basal planes perpendicular to the surface would be evolved in the coatings. Humidity has a minor influence on the coatings that have (002) basal plane orientation, whereas the tribological properties of MoSx coatings with edge orientations are greatly affected by humidity. The mechanisms of coating growth and friction and wear processes are discussed.
文摘MoS coatings were prepared by means of bipolar-pulsed DC magnetron sputtering on different substrate type at various temperature. The structure and fretting behavior of MoS, coatings have been determined respectively by XRD and fretting tester in air of 10% to 90% RH and under the load of 1 to 10 N. With increasing substrate temperature, the edge orientation evolves in the MoSx coating, and the relative content of edge-to-basal orientation becomes large. The tribological performance of coatings gets deteriorated. Compared with MoS, coatings on TiN/H13, CrN/H13 and MoS /Ti multilayer, MoS coating on H13 substrate has a lower load bearing capacity, and worn away easily under higher normal load 5N or ION and in air of 90% RH during the fretting process. The friction and wear properties of MoS, coatings on TiN/H13 and CrN/H13 (dual-layer) are slight better than that of MoS, /Ti multilayer under the normal load tested and in air of<10%to90%RH.
文摘MoSx (x = 1.79 ￣ 2.34) films of 200 nm thickness are deposited onto brass and C20 steel substrates by the ion beam assisted technique, respectively. Structures and compositions of these films, and changes in valence states of the Mo element are examined by XRD and XPS before and after wear. The lubrication properties and wear resistances for two kinds of samples are evaluated using a pin-on-disk installation in atmosphere at the room temperature. Tribo-wear behaviours and the microstructures between two kinds of samples exhibit obvious differences.
