The objective of the present work is to investigate the effect of various sputtering parameters such as nitrogen flow rate, deposition time and sputtering pressure on structural, wettability and optical properties of ...The objective of the present work is to investigate the effect of various sputtering parameters such as nitrogen flow rate, deposition time and sputtering pressure on structural, wettability and optical properties of titanium oxynitride films deposited on glass substrate by reactive magnetron sputtering. The X-ray diffraction graphs of titanium oxynitride films show evolution of various textures of TiO=N and TiN phases with increasing nitrogen flow rate and deposition time, but an increase in sputtering pressure from 4.0 to 8.0 Pa results in decline of various textures observed for TiO=Ny and TiN phases. The stress and strain calculated by sin2~ method are compressive, which decrease with increasing nitrogen flow rate from 55 to I00 sccm （standard cubic centimeter per minute） and increase with increasing deposition time from 80 to I40 min due to atomic penning effect and increasing thickness of the deposited films. The titanium oxynitride films have contact angle values above 90 deg., indicating that films are hydrophobic. The maximum contact angle of I09.1 deg. is observed at deposition time of 140 min. This water repellent property can add value to potential protective, wear and corrosion resistant application of titanium oxynitride films. The band gap decreases from 1.98 to 1.83 eV as nitrogen flow rate is increased from 55 to 100 sccm; it decreases from 1.93 to 1.79 eV as deposition time is increased from 80 to 140 min as more nitrogen incorporation results in higher negative potential of valence band N2p orbital. But it increases from 2.26 to 2.34 eV for titanium oxynitride films as sputtering pressure increases from 4.0 to 8.0 Pa.展开更多
NiTi shape memory alloys（SMA） have many biomedical applications due to their excellent mechanical and biocompatible properties. However, nickel in the alloy may cause allergic and toxic reactions, which limit some a...NiTi shape memory alloys（SMA） have many biomedical applications due to their excellent mechanical and biocompatible properties. However, nickel in the alloy may cause allergic and toxic reactions, which limit some applications. In this work, titanium oxynitride films were deposited on NiTi samples by high vacuum magnetron sputtering for various nitrogen and oxygen gas flow rates. The x-ray diffraction（XRD） and x-ray photoelectron spectroscopy（XPS） results reveal the presence of different phases in the titanium oxynitride thin films. Energy dispersive spectroscopy（EDS） elemental mapping of samples after immersion in simulated body fluids（SBF） shows that Ni is depleted from the surface and cell cultures corroborate the enhanced biocompatibility in vitro.展开更多
Ti-based materials are among the most widely studied catalysts for the oxygen reduction reaction(ORR).However,the actual roles of the catalytically active sites in N-doped Ti-based electrocatalysts are still unclear.I...Ti-based materials are among the most widely studied catalysts for the oxygen reduction reaction(ORR).However,the actual roles of the catalytically active sites in N-doped Ti-based electrocatalysts are still unclear.In this work,TiO_(2)and TiN were used as the precursors for the thermal nitridation and oxidation reactions at high temperatures,respectively.Titanium oxynitride(TiO_(x)N_(y))species with abundant oxygen defects,formed on the surface of the as-prepared catalysts,were found to play an essential role to achieve the uniform distribution of ultrafine Pt nanoparticles via atomic layer deposition,thereby enhancing the ORR performance.The TiN-supported Pt catalyst showed excellent ORR performance and stability in acidic conditions,with an onset potential of 0.88 V and a half-wave potential of 0.76 V(vs.RHE).The catalyst also delivered a mass activity of 112 A gPt-1,which is 1.9 times higher than that of commercial Pt/C.A combination of experiments and characterizations confirmed that the synergistic effects between the outer TiO_(x)N_(y)shell with abundant oxygen defects and the high-conductivity TiN core contribute to the enhanced ORR performance.The present work sheds light on the essential roles of oxygen defect-rich TiO_(x)N_(y)species in Ti-based electrocatalysts.展开更多
基金supported by the Council of Scientific and Industrial Research (CSIR)(Grant No.03(1148)/09/EMR-II)the Defence Research and Development Organisation (DRDO) (Grant No.ERIP/ER/0800354/M/011125)
文摘The objective of the present work is to investigate the effect of various sputtering parameters such as nitrogen flow rate, deposition time and sputtering pressure on structural, wettability and optical properties of titanium oxynitride films deposited on glass substrate by reactive magnetron sputtering. The X-ray diffraction graphs of titanium oxynitride films show evolution of various textures of TiO=N and TiN phases with increasing nitrogen flow rate and deposition time, but an increase in sputtering pressure from 4.0 to 8.0 Pa results in decline of various textures observed for TiO=Ny and TiN phases. The stress and strain calculated by sin2~ method are compressive, which decrease with increasing nitrogen flow rate from 55 to I00 sccm （standard cubic centimeter per minute） and increase with increasing deposition time from 80 to I40 min due to atomic penning effect and increasing thickness of the deposited films. The titanium oxynitride films have contact angle values above 90 deg., indicating that films are hydrophobic. The maximum contact angle of I09.1 deg. is observed at deposition time of 140 min. This water repellent property can add value to potential protective, wear and corrosion resistant application of titanium oxynitride films. The band gap decreases from 1.98 to 1.83 eV as nitrogen flow rate is increased from 55 to 100 sccm; it decreases from 1.93 to 1.79 eV as deposition time is increased from 80 to 140 min as more nitrogen incorporation results in higher negative potential of valence band N2p orbital. But it increases from 2.26 to 2.34 eV for titanium oxynitride films as sputtering pressure increases from 4.0 to 8.0 Pa.
基金Project supported by the Higher Education Commission,Hong Kong Research Grants Council(RGC)General Research Funds(GRF),China(Grant No.112212)the City University of Hong Kong Applied Research Grant(ARG),China(Grant No.9667066)
文摘NiTi shape memory alloys（SMA） have many biomedical applications due to their excellent mechanical and biocompatible properties. However, nickel in the alloy may cause allergic and toxic reactions, which limit some applications. In this work, titanium oxynitride films were deposited on NiTi samples by high vacuum magnetron sputtering for various nitrogen and oxygen gas flow rates. The x-ray diffraction（XRD） and x-ray photoelectron spectroscopy（XPS） results reveal the presence of different phases in the titanium oxynitride thin films. Energy dispersive spectroscopy（EDS） elemental mapping of samples after immersion in simulated body fluids（SBF） shows that Ni is depleted from the surface and cell cultures corroborate the enhanced biocompatibility in vitro.
基金supported by the National Natural Science Foundation of China(52225204 and 52173233)the Natural Science Foundation of Shanghai(23ZR1479200)+3 种基金the Innovation Program of Shanghai Municipal Education Commission(2021-01-07-00-03-E00109)“Shuguang Program”supported by Shanghai Education Development Foundation and Shanghai Municipal Education Commission(20SG33)the DHU Distinguished Young Professor Program.Q.X.acknowledges the Shanghai Pujiang Program(21PJ1400400)the Research Start-up Fund at DHU,and the Fundamental Research Funds for the Central Universities.H.D.U.acknowledges the 2022 Research Grant from Kangwon National University.
文摘Ti-based materials are among the most widely studied catalysts for the oxygen reduction reaction(ORR).However,the actual roles of the catalytically active sites in N-doped Ti-based electrocatalysts are still unclear.In this work,TiO_(2)and TiN were used as the precursors for the thermal nitridation and oxidation reactions at high temperatures,respectively.Titanium oxynitride(TiO_(x)N_(y))species with abundant oxygen defects,formed on the surface of the as-prepared catalysts,were found to play an essential role to achieve the uniform distribution of ultrafine Pt nanoparticles via atomic layer deposition,thereby enhancing the ORR performance.The TiN-supported Pt catalyst showed excellent ORR performance and stability in acidic conditions,with an onset potential of 0.88 V and a half-wave potential of 0.76 V(vs.RHE).The catalyst also delivered a mass activity of 112 A gPt-1,which is 1.9 times higher than that of commercial Pt/C.A combination of experiments and characterizations confirmed that the synergistic effects between the outer TiO_(x)N_(y)shell with abundant oxygen defects and the high-conductivity TiN core contribute to the enhanced ORR performance.The present work sheds light on the essential roles of oxygen defect-rich TiO_(x)N_(y)species in Ti-based electrocatalysts.
