Ferromagnetic Fe3O4 nanoparticles were synthesized using water as the solvent through the sol-gel method, which was selected for its cost-effectiveness, simplicity, and eco-friendly nature. The synthesized nanoparticl...Ferromagnetic Fe3O4 nanoparticles were synthesized using water as the solvent through the sol-gel method, which was selected for its cost-effectiveness, simplicity, and eco-friendly nature. The synthesized nanoparticles were characterized using a variety of techniques, including Fourier Transform Infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and Vibrating Sample Magnetometer (VSM). These characterizations confirmed the successful formation of Fe3O4 nanoparticles. The FTIR spectra identified characteristic peaks corresponding to the functional groups present, and XRD analysis, using Scherer’s equation, determined an average crystalline size of 1.2 nm for the Fe3O4 nanoparticles. TGA results demonstrated the thermal stability of the nanoparticles, SEM imaging revealed distinct honeycomb-like structures for the nanoparticles synthesized with water as the solvent, while the VSM analysis was used to determine the magnetic behavior of the nanoparticles.展开更多
High-temperature piezoelectric ceramics are critical for aerospace and other advanced applications,yet achieving high sensitivity and stability under elevated temperatures remains challenging.In this study,we employ a...High-temperature piezoelectric ceramics are critical for aerospace and other advanced applications,yet achieving high sensitivity and stability under elevated temperatures remains challenging.In this study,we employ a multi-element co-doping strategy combined with domain engineering to significantly enhance the piezoelectric performance and Curie temperature of Bi_(4)Ti_(3)O_(12)(BIT)-based ceramics.Using a solid-state reaction method,W^(6+)/Nb^(5+)/Ta^(5+)/Sb^(3+)non-equivalently co-doped BIT ceramics were synthesized,achieving a high piezoelectric coefficient(d33)of 35 pC N^(-1),an elevated Curie temperature of 687℃,and an increased resistivity of 2.9×10^(6)Ωcm at an optimal doping level of x=0.02.This study further reveals the impact of poling conditions on domain structure,providing new insights for enhancing piezoelectric properties through domain configuration.A second high-voltage,short-duration poling process promotes the formation of large domains,underscoring the role of domain rearrangement in augmenting piezoelectric activity.This work demonstrates the potential of BIT-based ceramics in hightemperature sensing and precision actuation applications,presenting a novel strategy for designing high-performance piezoelectric materials for extreme environments.展开更多
Here we report that the presence of MgCO_(3) stimulates the extracellular polymeric substance (EPS) secretion of Microcystis Aeruginosa (M. Aeruginosa). This stimulation led to a significant reduction in the total con...Here we report that the presence of MgCO_(3) stimulates the extracellular polymeric substance (EPS) secretion of Microcystis Aeruginosa (M. Aeruginosa). This stimulation led to a significant reduction in the total concentration of NH_(4)^(+)‒N by more than 86%, and effective recovery of PO_(4)^(3-)‒P within three days from concentrated wastewater (WW), although the secreted EPS inhibited the conversion of MgCO_(3) to specific crystal forms (MgNH4PO4.6H2O or MgHPO4.7H2O). Moreover, with an increase in PO_(4)^(3-) concentration in WW, these crystals appeared, thus the removal of NH_(4)^(+)‒N and PO_(4)^(3-)‒P nutrients can be attributed to the combined effect of M. Aeruginosa and MgCO_(3). We used Surface-Enhanced Raman Spectroscopy (SERS) combined with X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (FESEM-EDS), and X-ray Photoelectron Spectroscopy (XPS) to investigate the mechanism for competitive interactions between M. Aeruginosa and MgCO_(3) in removing NH_(4)^(+)‒N and PO_(4)^(3-)‒P. We identified that the bound EPS accumulated amorphous Mg–P–O dense particles on M. Aeruginosa, while soluble EPS, containing –COOH groups of humic-like substances decreased the pH of the solution and coordinated with Mg^(2+) ions. Therefore, both secreted bound and soluble EPS play a vital role in hindering the transformation of Mg^(2+) ions or MgCO_(3) to MgNH4PO4.6H2O or MgHPO4.7H2O crystals within WW, and they enhanced M. Aeruginosa 's ability in absorbing nutrients of NH_(4)^(+)‒N and PO_(4)^(3-)‒P. This mechanism plays a crucial role in the efficient recovery of NH_(4)^(+)‒N and PO_(4)^(3-)‒P from concentrated wastewater sources such as aerobically or anaerobically digested effluent from various sources like agriculture, livestock, and domestic wastewaters.展开更多
Regulating the orbital spin-electron filling of metal centers via interatomic electron transfer in transition metal oxides is one promising approach to enhancing their electrocatalytic oxygen evolution reaction(OER)pe...Regulating the orbital spin-electron filling of metal centers via interatomic electron transfer in transition metal oxides is one promising approach to enhancing their electrocatalytic oxygen evolution reaction(OER)performances,while it is still a challenge due to lacking of efficient strategy and deep understanding.In this work,a facile strategy containing electrochemical deposition and annealing in air atmosphere has been proposed to introduce monodispersed neodymium(Nd)atoms into spinel Co_(3)O_(4)nanosheets to trigger the electron transfer.Accordingly,the as-prepared Nd doped Co_(3)O_(4)nanosheets(Nd/Co_(3)O_(4))on nickel foam or carbon cloth showed greatly enhanced OER performances,with low overpotential of 284 and 396 mV at 10 m A cm^(-2),small Tafel slope of 95 and 119 mV dec^(-1)in 1.0 M KOH and 0.5 M H_(2)SO_(4),respectively.The experimental and density function theory results coherently indicate that the charge transfer in the Nd-O-Co asymmetric configuration not only enhances the conductivity of Co_(3)O_(4),but also regulates the filling degree of egorbitals of Co,leading to higher spin states,optimized adsorption ability,and accelerated H_(2)O dissociation process,thus achieving boosted OER activity.展开更多
文摘Ferromagnetic Fe3O4 nanoparticles were synthesized using water as the solvent through the sol-gel method, which was selected for its cost-effectiveness, simplicity, and eco-friendly nature. The synthesized nanoparticles were characterized using a variety of techniques, including Fourier Transform Infrared (FTIR) spectroscopy, X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and Vibrating Sample Magnetometer (VSM). These characterizations confirmed the successful formation of Fe3O4 nanoparticles. The FTIR spectra identified characteristic peaks corresponding to the functional groups present, and XRD analysis, using Scherer’s equation, determined an average crystalline size of 1.2 nm for the Fe3O4 nanoparticles. TGA results demonstrated the thermal stability of the nanoparticles, SEM imaging revealed distinct honeycomb-like structures for the nanoparticles synthesized with water as the solvent, while the VSM analysis was used to determine the magnetic behavior of the nanoparticles.
基金financially supported by the National Natural Science Foundation of China(No.52172135)the Youth Top Talent Project of the National Special Support Program(No.2021-527-07)+1 种基金the Leading Talent Project of the National Special Support Program(No.2022WRLJ003)Guangdong Basic and Applied Basic Research Foundation for Distinguished Young Scholars(Nos.2022B1515020070 and 2021B1515020083)
文摘High-temperature piezoelectric ceramics are critical for aerospace and other advanced applications,yet achieving high sensitivity and stability under elevated temperatures remains challenging.In this study,we employ a multi-element co-doping strategy combined with domain engineering to significantly enhance the piezoelectric performance and Curie temperature of Bi_(4)Ti_(3)O_(12)(BIT)-based ceramics.Using a solid-state reaction method,W^(6+)/Nb^(5+)/Ta^(5+)/Sb^(3+)non-equivalently co-doped BIT ceramics were synthesized,achieving a high piezoelectric coefficient(d33)of 35 pC N^(-1),an elevated Curie temperature of 687℃,and an increased resistivity of 2.9×10^(6)Ωcm at an optimal doping level of x=0.02.This study further reveals the impact of poling conditions on domain structure,providing new insights for enhancing piezoelectric properties through domain configuration.A second high-voltage,short-duration poling process promotes the formation of large domains,underscoring the role of domain rearrangement in augmenting piezoelectric activity.This work demonstrates the potential of BIT-based ceramics in hightemperature sensing and precision actuation applications,presenting a novel strategy for designing high-performance piezoelectric materials for extreme environments.
基金supported by Cultivating Fund Project of Hubei Hongshan Laboratory(2022hspy002).
文摘Here we report that the presence of MgCO_(3) stimulates the extracellular polymeric substance (EPS) secretion of Microcystis Aeruginosa (M. Aeruginosa). This stimulation led to a significant reduction in the total concentration of NH_(4)^(+)‒N by more than 86%, and effective recovery of PO_(4)^(3-)‒P within three days from concentrated wastewater (WW), although the secreted EPS inhibited the conversion of MgCO_(3) to specific crystal forms (MgNH4PO4.6H2O or MgHPO4.7H2O). Moreover, with an increase in PO_(4)^(3-) concentration in WW, these crystals appeared, thus the removal of NH_(4)^(+)‒N and PO_(4)^(3-)‒P nutrients can be attributed to the combined effect of M. Aeruginosa and MgCO_(3). We used Surface-Enhanced Raman Spectroscopy (SERS) combined with X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (FESEM-EDS), and X-ray Photoelectron Spectroscopy (XPS) to investigate the mechanism for competitive interactions between M. Aeruginosa and MgCO_(3) in removing NH_(4)^(+)‒N and PO_(4)^(3-)‒P. We identified that the bound EPS accumulated amorphous Mg–P–O dense particles on M. Aeruginosa, while soluble EPS, containing –COOH groups of humic-like substances decreased the pH of the solution and coordinated with Mg^(2+) ions. Therefore, both secreted bound and soluble EPS play a vital role in hindering the transformation of Mg^(2+) ions or MgCO_(3) to MgNH4PO4.6H2O or MgHPO4.7H2O crystals within WW, and they enhanced M. Aeruginosa 's ability in absorbing nutrients of NH_(4)^(+)‒N and PO_(4)^(3-)‒P. This mechanism plays a crucial role in the efficient recovery of NH_(4)^(+)‒N and PO_(4)^(3-)‒P from concentrated wastewater sources such as aerobically or anaerobically digested effluent from various sources like agriculture, livestock, and domestic wastewaters.
基金support from the Natural Science Foundation and Overseas Talent Projects of Jiangxi Province(20242BAB25217,20232BAB214025,20232BCJ25044)the Jiangxi Provincial Natural Science Foundation(20232BAB204088)the National Natural Science Foundation of China(52402132)。
文摘Regulating the orbital spin-electron filling of metal centers via interatomic electron transfer in transition metal oxides is one promising approach to enhancing their electrocatalytic oxygen evolution reaction(OER)performances,while it is still a challenge due to lacking of efficient strategy and deep understanding.In this work,a facile strategy containing electrochemical deposition and annealing in air atmosphere has been proposed to introduce monodispersed neodymium(Nd)atoms into spinel Co_(3)O_(4)nanosheets to trigger the electron transfer.Accordingly,the as-prepared Nd doped Co_(3)O_(4)nanosheets(Nd/Co_(3)O_(4))on nickel foam or carbon cloth showed greatly enhanced OER performances,with low overpotential of 284 and 396 mV at 10 m A cm^(-2),small Tafel slope of 95 and 119 mV dec^(-1)in 1.0 M KOH and 0.5 M H_(2)SO_(4),respectively.The experimental and density function theory results coherently indicate that the charge transfer in the Nd-O-Co asymmetric configuration not only enhances the conductivity of Co_(3)O_(4),but also regulates the filling degree of egorbitals of Co,leading to higher spin states,optimized adsorption ability,and accelerated H_(2)O dissociation process,thus achieving boosted OER activity.
