The room temperature stabled monoclinic KNbO3 nanowires were found to act as photocatalyst for photocatalytic methane production and dye degradation in this work. Higher activities have been observed for monoclinic ph...The room temperature stabled monoclinic KNbO3 nanowires were found to act as photocatalyst for photocatalytic methane production and dye degradation in this work. Higher activities have been observed for monoclinic phase compared to the reference（orthorhombic phase）. In the photoreduction of CO2 reaction, the monoclinic KNbO3 nanowires exhibited a CH4 evolution rate of 0.025 μmol·g-1·h-1, which was higher than 0.021 μmol·g-1·h-1 of orthorhombic KNbO3 nanowires. In the photodegradation of rhodamine B（Rh B）, almost all the Rh B were degraded after 90 min light illumination for monoclinic KNbO3 nanowires. But for orthorhombic KNbO3 nanowires, the concentration of Rh B only decreased to 62% of the initial value.展开更多
Skeletal form of KNbO3 crystals growing in Li2B4O7 solvent was in-situ observed at 900℃ and it was found that shallow depression started to develop on the surface of KNbO3 crystals when the crystal size exceeded seve...Skeletal form of KNbO3 crystals growing in Li2B4O7 solvent was in-situ observed at 900℃ and it was found that shallow depression started to develop on the surface of KNbO3 crystals when the crystal size exceeded several micron, typically 7 micron. Based on the quantitative criterion derived by Chernov, the estimated critical size of KNbO3 crystals was 1 micron, which was consistent with the experimental measurement. The kinetic coefficients, kcorner and kcr, in the criterion were experimentally obtained in the diffusive-convective and diffusive-advective flow states respectively.展开更多
The development of fully solution-processed,biodegradable piezoelectrics is a critical step in the development of green electronics towards the worldwide reduction of harmful electronic waste.However,recent printing p...The development of fully solution-processed,biodegradable piezoelectrics is a critical step in the development of green electronics towards the worldwide reduction of harmful electronic waste.However,recent printing processes for piezoelectrics are hindered by the high sintering temperatures required for conventional perovskite fabrication techniques.Thus,a process was developed to manufacture lead-free printed piezoelectric devices at low temperatures to enable integration with eco-friendly substrates and electrodes.A printable ink was developed for screen printing potassium niobate(KNbO3)piezoelectric layers in microns of thickness at a maximum processing temperature of 120℃ with high reproducibility.Characteristic parallel plate capacitor and cantilever devices were designed and manufactured to assess the quality of this ink and evaluate its physical,dielectric,and piezoelectric characteristics;including a comparison of behaviour between conventional silicon and biodegradable paper substrates.The printed layers were 10.7–11.2μm thick,with acceptable surface roughness values in the range of 0.4-1.1μm.The relative permittivity of the piezoelectric layer was 29.3.The poling parameters were optimised for the piezoelectric response,with an average longitudinal piezoelectric coefficient for samples printed on paper substrates measured as d33,eff,paper=13.57±2.84 pC/N;the largest measured value was 18.37 pC/N on paper substrates.This approach to printable biodegradable piezoelectrics opens the way forward for fully solution-processed green piezoelectric devices.展开更多
Z-Schemc photocatalysts as a research locus pertomi strong redox capability and high photocatalytic peribnnance.WO3/KNbO3 photocatalysts were fabricated by ball milling method,and performed higlier photocatalytic acti...Z-Schemc photocatalysts as a research locus pertomi strong redox capability and high photocatalytic peribnnance.WO3/KNbO3 photocatalysts were fabricated by ball milling method,and performed higlier photocatalytic activity in liquid degradation(rhodamine B,methylene blue and bisphenol A),compared with WO3 or KNbO3 monomer.This is due to that Z-scheme heterojunction is lonned between WO3 and KNbO3,and the holes photo-excited in valence band of KNbO?are quickly combined with the electrons in conduction band of WO3.The electrons accumulated in conduction band of KNbO3 show high reducibility,thereby reducing O2 to·O 2-,and the holes in valence band of WO3 show high oxidative to oxidize H2O to·OH,respectively.Furthermore,it is proved by means of electron spin resonaiice(ESR)spectra,terephthalic acid photolumiiiescence probing technique(TA・PL),and UV-Vis absorption spectra of nitroblue tetrazolium.This work indicates that the iabrication of Z-scheme structure can improve the photocatalytic activity by efficiently separating the photogenerated electrons and holes in the photocatalytic reaction system,which is helpful to deeply understand the migration mechanism of photoexcited cairier(band-band transfer and Z-scheme transfer)in heterojunction photocatalysts.展开更多
基金supported by the National Basic Research Program of China(973 Program,2013CB632400)the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe National Natural Science Foundation of China(Nos.51272102 and 21103070)
文摘The room temperature stabled monoclinic KNbO3 nanowires were found to act as photocatalyst for photocatalytic methane production and dye degradation in this work. Higher activities have been observed for monoclinic phase compared to the reference（orthorhombic phase）. In the photoreduction of CO2 reaction, the monoclinic KNbO3 nanowires exhibited a CH4 evolution rate of 0.025 μmol·g-1·h-1, which was higher than 0.021 μmol·g-1·h-1 of orthorhombic KNbO3 nanowires. In the photodegradation of rhodamine B（Rh B）, almost all the Rh B were degraded after 90 min light illumination for monoclinic KNbO3 nanowires. But for orthorhombic KNbO3 nanowires, the concentration of Rh B only decreased to 62% of the initial value.
基金The present work was supported by the foundation for key research project of microgravity science from the State Science andTechnology Commission of China(95-Yu-34)the National Natural Science Foundation of China under grant No.59832080.
文摘Skeletal form of KNbO3 crystals growing in Li2B4O7 solvent was in-situ observed at 900℃ and it was found that shallow depression started to develop on the surface of KNbO3 crystals when the crystal size exceeded several micron, typically 7 micron. Based on the quantitative criterion derived by Chernov, the estimated critical size of KNbO3 crystals was 1 micron, which was consistent with the experimental measurement. The kinetic coefficients, kcorner and kcr, in the criterion were experimentally obtained in the diffusive-convective and diffusive-advective flow states respectively.
基金funding from Swiss National Science Foundation (Grant No.179064).
文摘The development of fully solution-processed,biodegradable piezoelectrics is a critical step in the development of green electronics towards the worldwide reduction of harmful electronic waste.However,recent printing processes for piezoelectrics are hindered by the high sintering temperatures required for conventional perovskite fabrication techniques.Thus,a process was developed to manufacture lead-free printed piezoelectric devices at low temperatures to enable integration with eco-friendly substrates and electrodes.A printable ink was developed for screen printing potassium niobate(KNbO3)piezoelectric layers in microns of thickness at a maximum processing temperature of 120℃ with high reproducibility.Characteristic parallel plate capacitor and cantilever devices were designed and manufactured to assess the quality of this ink and evaluate its physical,dielectric,and piezoelectric characteristics;including a comparison of behaviour between conventional silicon and biodegradable paper substrates.The printed layers were 10.7–11.2μm thick,with acceptable surface roughness values in the range of 0.4-1.1μm.The relative permittivity of the piezoelectric layer was 29.3.The poling parameters were optimised for the piezoelectric response,with an average longitudinal piezoelectric coefficient for samples printed on paper substrates measured as d33,eff,paper=13.57±2.84 pC/N;the largest measured value was 18.37 pC/N on paper substrates.This approach to printable biodegradable piezoelectrics opens the way forward for fully solution-processed green piezoelectric devices.
基金Supported by the National Natural Science Foundation of China(Nos.51472005,51772118 and 21607027)the Natural Science Foundation of Anhui Province,China(No.1608085QB37)+3 种基金the Open Project Program of the State Key Laboratory of Photocatalysis on Energy and Environment,Fuzhou University,China(No.SKLPEE-KF201804)the Natural Science Foundation of Educational Conunittee of Anhui Province,China(Nos.KJ2018A0387 and KJ2019A0601)the Project of Aiiliui Province tor Excellent Young Talents in Universities,Cliina(No.gxyq2019029)the Graduate Innovation Foundation of Huaibei Nonnal University,China(No.ycx201901003)。
文摘Z-Schemc photocatalysts as a research locus pertomi strong redox capability and high photocatalytic peribnnance.WO3/KNbO3 photocatalysts were fabricated by ball milling method,and performed higlier photocatalytic activity in liquid degradation(rhodamine B,methylene blue and bisphenol A),compared with WO3 or KNbO3 monomer.This is due to that Z-scheme heterojunction is lonned between WO3 and KNbO3,and the holes photo-excited in valence band of KNbO?are quickly combined with the electrons in conduction band of WO3.The electrons accumulated in conduction band of KNbO3 show high reducibility,thereby reducing O2 to·O 2-,and the holes in valence band of WO3 show high oxidative to oxidize H2O to·OH,respectively.Furthermore,it is proved by means of electron spin resonaiice(ESR)spectra,terephthalic acid photolumiiiescence probing technique(TA・PL),and UV-Vis absorption spectra of nitroblue tetrazolium.This work indicates that the iabrication of Z-scheme structure can improve the photocatalytic activity by efficiently separating the photogenerated electrons and holes in the photocatalytic reaction system,which is helpful to deeply understand the migration mechanism of photoexcited cairier(band-band transfer and Z-scheme transfer)in heterojunction photocatalysts.
