A phase-pure NaTi2（PO4）3/reduced graphene oxide （rGO） nanocomposite was prepared using a microwave-assisted one-pot method and subsequent heat treatment. The well-crystallized NaTi2（PO4）3 nanoparticles （30-40 n...A phase-pure NaTi2（PO4）3/reduced graphene oxide （rGO） nanocomposite was prepared using a microwave-assisted one-pot method and subsequent heat treatment. The well-crystallized NaTi2（PO4）3 nanoparticles （30-40 nm） were uniformly precipitated on rGO templates through Ti-O-C bonds. The chemical interactions between the NaTi2（PO4）3 nanoparticles and rGO could immobilize the NaTi2（PO4）3 nanoparticles on the rGO sheets, which might be responsible for the excellent electrochemical performance of the nanocomposite. The NaTi2（PO4）B/rGO nanocomposite exhibited a specific capacity of 128.6 mA-h.g-1 approaching the theoretical value at a 0.1 C-rate with an excellent rate capability （72.9% capacity retention at 50 C-rate） and cycling performance （only 4.5% capacity loss after 1,000 cycles at a high rate of 10 C）. These properties were maintained even when the electrodes were prepared without the use of an additional conducting agent. The excellent sodium storage properties of the NaTi2（PO4）B/rGO nanocomposite could be attributed to the nano-sized NaTi2（PO4）3 particles, which significantly reduced the transport lengths for Na＋ ions, and an intimate contact between the NaTi2（PO4）3 particles and rGO due to chemical bonding.展开更多
By means of in situ diffuse reflectance FTIR, the IR spectra of 6 coals with different ranks were obtained from room temperature to 230 ℃. A new curve fitting method was used to recognize the different hydrogen ...By means of in situ diffuse reflectance FTIR, the IR spectra of 6 coals with different ranks were obtained from room temperature to 230 ℃. A new curve fitting method was used to recognize the different hydrogen bonds in the coals, and the influence of coal ranks on the distribution of hydrogen bonds(HBs) in the coals and their thermal stability were discussed. The results show that there is another new HB(around 2514 cm -1 ) between the -SH in mercaptans or thiophenols and the nitrogen in the pyridine like compounds in the coals, and the evidence for that was provided. The controversial band of the HB between hydroxyl and the nitrogen of the pyridine like compounds was determined in the range of 3028-2984 cm -1 , and the result is consistent with but more specific than that of Painter et al .. It was found that the stability of different HBs in the coals is influenced by both coal rank and temperature. For some HBs, the higher the coal rank, the higher the stability of them. Within the temperature range of our research, the stability of the HB between the hydroxyl and the π bond increases to some extent for some coals at temperatures higher than 110 or 140 ℃.展开更多
Nowadays,Zinc(Zn)-based biocomposites as biodegradable implant materials have been recognized as a promising approach to overcome the insufficient mechanical performance of Zn matrix and to endow the Zn-based material...Nowadays,Zinc(Zn)-based biocomposites as biodegradable implant materials have been recognized as a promising approach to overcome the insufficient mechanical performance of Zn matrix and to endow the Zn-based materials with biofunctionality.However,the strengthening effect on Zn-based matrix compos-ite remains far from expectation mainly due to the poor interfacial bonding between the reinforcement and Zn matrix,and the relatively coarse grain size of the Zn matrix.Herein,we have developed a novel in situ wetting strategy to ameliorate the interfacial bonding and mechanical performance of Zn-Ag-based composites using cuprous oxide-modified graphene oxide(Cu_(2)O-GO)sheets as reinforcement.The en-hanced interfacial bonding between GO sheets and Zn matrix owing to the in situ generated ZnO inter-layer and the ultrafine microstructure with an average grain size of 360 nm were simultaneously achieved in the hot extruded(HEed)1 wt%Cu_(2)O-GO/Zn-2 wt%Ag biocomposites.Consequently,HEed biocompos-ites possessed excellent tensile properties,including ultimate tensile strength(UTS)of 344.0±2.4 MPa,yield stress(YS)of 314.0±4.8 MPa,and elongation at failure of 15.5%±1.3%.Ultrafine and uniform microstructure of the HEed biocomposites resulted in a relatively uniform corrosion morphology and a degradation rate of 0.195±0.004 mm y^(−1) in simulated body fluid(SBF)solution.The 2-fold diluted extract of the HEed biocomposites exhibited satisfying cytocompatibility with MC3T3-E1 pre-osteoblast comparable to that of Ti-6Al-4 V ELI alloys.More importantly,the synergistic effect of metallic ions,Ag-rich nanoparticles,and GO sheets contributed to the remarkable antibacterial activity of the experimental biocomposites against both S.aureus and E.coli.These results demonstrated that the 1Cu_(2)O-GO/Zn-2Ag biocomposites should be anticipated as a promising biodegradable material for orthopedic applications.展开更多
文摘A phase-pure NaTi2（PO4）3/reduced graphene oxide （rGO） nanocomposite was prepared using a microwave-assisted one-pot method and subsequent heat treatment. The well-crystallized NaTi2（PO4）3 nanoparticles （30-40 nm） were uniformly precipitated on rGO templates through Ti-O-C bonds. The chemical interactions between the NaTi2（PO4）3 nanoparticles and rGO could immobilize the NaTi2（PO4）3 nanoparticles on the rGO sheets, which might be responsible for the excellent electrochemical performance of the nanocomposite. The NaTi2（PO4）B/rGO nanocomposite exhibited a specific capacity of 128.6 mA-h.g-1 approaching the theoretical value at a 0.1 C-rate with an excellent rate capability （72.9% capacity retention at 50 C-rate） and cycling performance （only 4.5% capacity loss after 1,000 cycles at a high rate of 10 C）. These properties were maintained even when the electrodes were prepared without the use of an additional conducting agent. The excellent sodium storage properties of the NaTi2（PO4）B/rGO nanocomposite could be attributed to the nano-sized NaTi2（PO4）3 particles, which significantly reduced the transport lengths for Na＋ ions, and an intimate contact between the NaTi2（PO4）3 particles and rGO due to chemical bonding.
基金Supported by the National Natural Science Foundation of China(No.2 990 6 0 12)
文摘By means of in situ diffuse reflectance FTIR, the IR spectra of 6 coals with different ranks were obtained from room temperature to 230 ℃. A new curve fitting method was used to recognize the different hydrogen bonds in the coals, and the influence of coal ranks on the distribution of hydrogen bonds(HBs) in the coals and their thermal stability were discussed. The results show that there is another new HB(around 2514 cm -1 ) between the -SH in mercaptans or thiophenols and the nitrogen in the pyridine like compounds in the coals, and the evidence for that was provided. The controversial band of the HB between hydroxyl and the nitrogen of the pyridine like compounds was determined in the range of 3028-2984 cm -1 , and the result is consistent with but more specific than that of Painter et al .. It was found that the stability of different HBs in the coals is influenced by both coal rank and temperature. For some HBs, the higher the coal rank, the higher the stability of them. Within the temperature range of our research, the stability of the HB between the hydroxyl and the π bond increases to some extent for some coals at temperatures higher than 110 or 140 ℃.
基金This work was financially supported by the Tianjin Natural Sci-ence Foundation(Nos.20JCQNJC00610 and 20JCYBJC00620)the National Natural Science Foundation of China(Nos.51871166 and U1764254).
文摘Nowadays,Zinc(Zn)-based biocomposites as biodegradable implant materials have been recognized as a promising approach to overcome the insufficient mechanical performance of Zn matrix and to endow the Zn-based materials with biofunctionality.However,the strengthening effect on Zn-based matrix compos-ite remains far from expectation mainly due to the poor interfacial bonding between the reinforcement and Zn matrix,and the relatively coarse grain size of the Zn matrix.Herein,we have developed a novel in situ wetting strategy to ameliorate the interfacial bonding and mechanical performance of Zn-Ag-based composites using cuprous oxide-modified graphene oxide(Cu_(2)O-GO)sheets as reinforcement.The en-hanced interfacial bonding between GO sheets and Zn matrix owing to the in situ generated ZnO inter-layer and the ultrafine microstructure with an average grain size of 360 nm were simultaneously achieved in the hot extruded(HEed)1 wt%Cu_(2)O-GO/Zn-2 wt%Ag biocomposites.Consequently,HEed biocompos-ites possessed excellent tensile properties,including ultimate tensile strength(UTS)of 344.0±2.4 MPa,yield stress(YS)of 314.0±4.8 MPa,and elongation at failure of 15.5%±1.3%.Ultrafine and uniform microstructure of the HEed biocomposites resulted in a relatively uniform corrosion morphology and a degradation rate of 0.195±0.004 mm y^(−1) in simulated body fluid(SBF)solution.The 2-fold diluted extract of the HEed biocomposites exhibited satisfying cytocompatibility with MC3T3-E1 pre-osteoblast comparable to that of Ti-6Al-4 V ELI alloys.More importantly,the synergistic effect of metallic ions,Ag-rich nanoparticles,and GO sheets contributed to the remarkable antibacterial activity of the experimental biocomposites against both S.aureus and E.coli.These results demonstrated that the 1Cu_(2)O-GO/Zn-2Ag biocomposites should be anticipated as a promising biodegradable material for orthopedic applications.
