In this study,cyclohexene was used as a representative of olefin and catalyzed by CeY zeolites in a fixedbed reactor under mild conditions,and the influence of Ce species in hydride transfer reaction over CeY zeolites...In this study,cyclohexene was used as a representative of olefin and catalyzed by CeY zeolites in a fixedbed reactor under mild conditions,and the influence of Ce species in hydride transfer reaction over CeY zeolites was evaluated.CeY zeolites show more excellent hydride transfer properties than HY zeolite.Based on the results of almost identical Bronsted acid properties but not the product distributions for 0.075 CeY and 0.075 CeY(DC)samples,it should be suggested that the Bronsted acid strength and density are not the deciding factors to the hydride transfer reaction.A unique band at 1442 cm^-1 in situ FTIR spectroscopy spectra are assigned to pyridine complexes bonded to a class of active Ce species that could reversibly migrate from the core of SOD cages to its 6-rings mouth towards the supercages.These results provide valuable information that these active Ce species should play a synergistic role with the Bronsted acid sites in enhancing the hydride transfer reaction with a bimolecular mechanism over CeY zeolites.展开更多
A waveguide optical isolator with a CeY2Fe5O12 guiding layer employing a nonreciprocal phase shift was studied. The isolation ratio of more than 12.2 dB was achieved at a wavelength of 1.55μm.
Na-Se batteries have caught tremendous attention because of natural abundant of element sodium and their high volumetric energy density(2530 Wh/L).However,the low utilization ratio of Se is the main obstacle for pract...Na-Se batteries have caught tremendous attention because of natural abundant of element sodium and their high volumetric energy density(2530 Wh/L).However,the low utilization ratio of Se is the main obstacle for practical application.Herein,an advanced Se-based electrode is designed and prepared by using tea stem-derived micropore carbon matrix(TSC)as Se host and coating TSC/Se with cyclic polyacrylonitrile(cPAN).TSC/Se/cPAN electrode shows rate capacity of 318.3 mAh/g at 2 C(1 C=675 mA/g)and great discharge capacity of 420.6 mAh/g after 300 cycles at 0.2 C.The impressive electrochemical performance is mainly ascribed to the interface design of c PAN coating,resulting in the enhanced electronic conductivity of whole electrode and high ratio of robust inorganic salt NaCl in CEI film.The TSC/Se/c PAN||NVP full cell also exhibits great discharge capacity of 556.6 mAh/g after 55 cycles at 0.1 C.展开更多
The development of a uniform,electrochemically robust coating capable of reconciling structural integrity with chemical inertness at high voltages is pivotal for unlocking the full potential of layered lithiumrich cat...The development of a uniform,electrochemically robust coating capable of reconciling structural integrity with chemical inertness at high voltages is pivotal for unlocking the full potential of layered lithiumrich cathodes(LRNCM).Herein,an atomic-scale LiNbO_(3) coating is constructed on LRNCM via atomic layer deposition(ALD),which dual-functionalizes as a chemical passivator and mechanical stabilizer to address concurrent interfacial and bulk degradation.The conformal LiNbO_(3) layer suppresses nucleophilic attacks by reactive oxygen species in carbonate electrolytes,redirecting cathode-electrolyte interphase(CEI)evolution toward an inorganic-dominated architecture with high ionic conductivity.This optimized CEI reduces interfacial impedance and charge-transfer polarization.Furthermore,the LiNbO_(3) coating functions as a mechanical buffer to suppress anisotropic lattice strain and inhibit phase transitions from layered to spinel structures.The synergistic stabilization enables the LiNbO_(3)-coated cathode to deliver exceptional cyclability,retaining 84.48%capacity and 80.27%energy density after 300 cycles at 1 C,with a voltage decay rate of 0.73 mV/cycle,outperforming the uncoated LRNCM(76.46%,71.76%,and 0.97 mV/cycle).By decoupling anionic redox activity from structural and interfacial degradation,this work establishes ALD-based surface engineering as a scalable paradigm for high-energy LRNCM,offering a materials-design blueprint to harmonize energy density with longevity in next-generation batteries.展开更多
基金Project supported by the National Natural Science Foundation of China(21902068,U1662135)PetroChina Company Limited(KYWX-18-011)Scientific Research Project of Education Department of Liaoning Province(L2019035)。
文摘In this study,cyclohexene was used as a representative of olefin and catalyzed by CeY zeolites in a fixedbed reactor under mild conditions,and the influence of Ce species in hydride transfer reaction over CeY zeolites was evaluated.CeY zeolites show more excellent hydride transfer properties than HY zeolite.Based on the results of almost identical Bronsted acid properties but not the product distributions for 0.075 CeY and 0.075 CeY(DC)samples,it should be suggested that the Bronsted acid strength and density are not the deciding factors to the hydride transfer reaction.A unique band at 1442 cm^-1 in situ FTIR spectroscopy spectra are assigned to pyridine complexes bonded to a class of active Ce species that could reversibly migrate from the core of SOD cages to its 6-rings mouth towards the supercages.These results provide valuable information that these active Ce species should play a synergistic role with the Bronsted acid sites in enhancing the hydride transfer reaction with a bimolecular mechanism over CeY zeolites.
文摘A waveguide optical isolator with a CeY2Fe5O12 guiding layer employing a nonreciprocal phase shift was studied. The isolation ratio of more than 12.2 dB was achieved at a wavelength of 1.55μm.
基金financially supported by Fujian Science and Technology Planning Projects of China(Nos.2022T3067 and 2023H0045)the Self-deployment Project Research Programs of Haixi Institutes,Chinese Academy of Sciences(No.CXZX2022-JQ12)the XIREM autonomously deployment project(No.2023GG02)。
文摘Na-Se batteries have caught tremendous attention because of natural abundant of element sodium and their high volumetric energy density(2530 Wh/L).However,the low utilization ratio of Se is the main obstacle for practical application.Herein,an advanced Se-based electrode is designed and prepared by using tea stem-derived micropore carbon matrix(TSC)as Se host and coating TSC/Se with cyclic polyacrylonitrile(cPAN).TSC/Se/cPAN electrode shows rate capacity of 318.3 mAh/g at 2 C(1 C=675 mA/g)and great discharge capacity of 420.6 mAh/g after 300 cycles at 0.2 C.The impressive electrochemical performance is mainly ascribed to the interface design of c PAN coating,resulting in the enhanced electronic conductivity of whole electrode and high ratio of robust inorganic salt NaCl in CEI film.The TSC/Se/c PAN||NVP full cell also exhibits great discharge capacity of 556.6 mAh/g after 55 cycles at 0.1 C.
基金the National Natural Science Foundation of China(Grant No.22409135,22109102,52472226,22075062,and U23A20573)the Guangdong Basic and Applied Basic Research Foundation(No.2025A1515011282)+5 种基金the Scientific Foundation for Youth Scholars of Shenzhen University(868-000001033364)the Heilongjiang Touyan Team(Grant No.HITTY-20190033)the Heilongjiang Province‘‘hundred million”project science and technology major special projects(2019ZX09A02)the Fundamental Research Funds for the Central Universities(Grant No.FRFCU5710051922)the High-Level Professional Team in Shenzhen(KQTD20210811090045006)the Shenzhen Science and Technology Program(JCYJ20210324120400002 and KJZD20240903100701003)。
文摘The development of a uniform,electrochemically robust coating capable of reconciling structural integrity with chemical inertness at high voltages is pivotal for unlocking the full potential of layered lithiumrich cathodes(LRNCM).Herein,an atomic-scale LiNbO_(3) coating is constructed on LRNCM via atomic layer deposition(ALD),which dual-functionalizes as a chemical passivator and mechanical stabilizer to address concurrent interfacial and bulk degradation.The conformal LiNbO_(3) layer suppresses nucleophilic attacks by reactive oxygen species in carbonate electrolytes,redirecting cathode-electrolyte interphase(CEI)evolution toward an inorganic-dominated architecture with high ionic conductivity.This optimized CEI reduces interfacial impedance and charge-transfer polarization.Furthermore,the LiNbO_(3) coating functions as a mechanical buffer to suppress anisotropic lattice strain and inhibit phase transitions from layered to spinel structures.The synergistic stabilization enables the LiNbO_(3)-coated cathode to deliver exceptional cyclability,retaining 84.48%capacity and 80.27%energy density after 300 cycles at 1 C,with a voltage decay rate of 0.73 mV/cycle,outperforming the uncoated LRNCM(76.46%,71.76%,and 0.97 mV/cycle).By decoupling anionic redox activity from structural and interfacial degradation,this work establishes ALD-based surface engineering as a scalable paradigm for high-energy LRNCM,offering a materials-design blueprint to harmonize energy density with longevity in next-generation batteries.
