Doping modification is one of the most effective ways to optimize the thermoelectric properties of Bi_(2)Te_(3)-based alloys.P-type Bi_(2−x)Sb_(x)Te_(3) thermoelectric materials have been successfully prepared by dire...Doping modification is one of the most effective ways to optimize the thermoelectric properties of Bi_(2)Te_(3)-based alloys.P-type Bi_(2−x)Sb_(x)Te_(3) thermoelectric materials have been successfully prepared by direct Sb doping method.It can be found that doping Sb into Bi_(2)Te_(3) lattice array for Bi-site replacement facilitates the generation of Sb′Te anti-site defects.This anti-site defects can increase the hole concentration and optimize electrical transport properties of Bi_(2−x)Sb_(x)Te_(3) alloys.In addition,the point defects induced by mass and stress fluctuations and the Sb impurities produced during the sintering process can enhance the multi-scale phonon scattering and reduce the lattice thermal conductivity.As a result,the Bi_(0.47)Sb_(1.63)Te_(3) sample has a maximum thermoelectric figure of merit ZT of 1.04 at 350 K.It is worth noting that the bipolar effect of Bi_(2)Te_(3)-based alloys can be weakened with the increase of Sb content.The Bi_(0.44)Sb_(1.66)Te_(3) sample has a maximum average ZT value(0.93)in the temperature range of 300–500 K,indicating that direct doping of Sb can broaden the temperature range corresponding to the optimal ZT value.This work provides an idea for developing high-performance near room temperature thermoelectric materials with a wide temperature range.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
The development of high-performance cathode materials is critical to the practical application of sodiumion batteries(SIBs).O3-type NaCrO_(2)(NCO)is one of the most competitive cathodes,but it suffers from rapid capac...The development of high-performance cathode materials is critical to the practical application of sodiumion batteries(SIBs).O3-type NaCrO_(2)(NCO)is one of the most competitive cathodes,but it suffers from rapid capacity decay caused by severe irreversible structural evolution.An Mg-Ti co-doped Na_(0.99)Cr_(0.95)Mg_(0.02)Ti_(0.03)O_(2)(NCO-MT)cathode material is designed and synthesized via a facile solid-state reaction to enhance the cyclability of NCO.A capacity retention of 71.6%after 2500 cycles with the capacity fade rate of 0.011%per cycle is achieved for NCO-MT at 5 C,which is attributed to the highly reversible crystal structure during cycling.Our findings offer a novel insight into the high-performance O3-type layered cathode materials for SIBs and are beneficial to promote the development of high-rate SIBs.展开更多
In this work,the TiO_(2)/Sb_(2)S_(3) nanorod arrays(NRAs)were synthesized through a two-stage hydrothermal route for photoelectrochemical(PEC)water splitting.The effect of annealing treatment in Ar ambience on the PEC...In this work,the TiO_(2)/Sb_(2)S_(3) nanorod arrays(NRAs)were synthesized through a two-stage hydrothermal route for photoelectrochemical(PEC)water splitting.The effect of annealing treatment in Ar ambience on the PEC activity of TiO_(2)/Sb_(2)S_(3) composite sample was investigated by electrochemical impedance analysis,including Nyquist and Mott-Schottky(M-S)plots.It was demonstrated that vacuum annealing could crystallize Sb_(2)S_(3) component and change its color from red to black,leading to an increment of photocurrent density from 1.9 A/m^(2) to 4.25 A/m^(2) at 0 V versus saturated calomel electrode(VSCE).The enhanced PEC performance was mainly attributed to the improved visible light absorption.Moreover,annealing treatment facilitated retarding the electron-hole recombination occurred at the solid/liquid interfaces.Our work might provide a novel strategy for enhancing the PEC performance of a semiconductor electrode.展开更多
Peroxymonosulfate(PMS)is commonly used in advanced oxidation processes to degrade organic pollutants in wastewater.In this work,to obtain better PMS activation efficiency,Bi_(4)O_(5)Br_(2)/BCZT(BBT)piezoelectric photo...Peroxymonosulfate(PMS)is commonly used in advanced oxidation processes to degrade organic pollutants in wastewater.In this work,to obtain better PMS activation efficiency,Bi_(4)O_(5)Br_(2)/BCZT(BBT)piezoelectric photocatalyst was designed.Abundant active radicals produced by BBT under visible light irradiation and ultrasonic vibration were used to activate PMS,thereby achieving rapid degradation of high concentration pollutants.With the introduction of BCZT,the catalyst has a strong internal electric field and three-dimensional lamellar structure,which promotes the separation and transfer of electrons and holes.It is worth noting that under optimal reaction conditions,the degradation rate of ARB reached 93%by BBT15 within 10 min.The catalytic experiment combined with the piezoelectric performance test results revealed the key role of piezoelectric photocatalytic reaction in PMS activation.This provides an important prospect for PMS to effectively deal with the degradation of high concentrations of organic pollutants.展开更多
The study of the effects of supercritical CO_(2)(ScCO_(2))under high temperature and high pressure on the mechanical properties and fracturing potential of shale holds significant implications for advancing our unders...The study of the effects of supercritical CO_(2)(ScCO_(2))under high temperature and high pressure on the mechanical properties and fracturing potential of shale holds significant implications for advancing our understanding of enhanced shale gas extraction and reservoir exploration and development.This study examines the influence of three fluids,i.e.ScCO_(2),deionized water(DW),and ScCO_(2)tDW,on the mechanical properties and fracturability of shale at immersion pressures of 15 MPa and 45 MPa,with a constant temperature of 100C.The key findings are as follows:(1)Uniaxial compressive strength(UCS)of shale decreased by 10.72%,11.95%,and 23.67%at 15 MPa,and by 42.40%,46.84%,and 51.65%at 45 MPa after immersion in ScCO_(2),DW,and ScCO_(2)tDW,respectively,with the most pronounced effect observed in ScCO_(2)tDW;(2)Microstructural analysis revealed that while ScCO_(2)and DW do not significantly alter the microstructure,immersion in ScCO_(2)tDW results in a more complex surface morphology;(3)Acoustic emission(AE)analysis indicates a reduction in stress for crack damage,with a decreased fractal dimension of AE signals in different fluids.AE energy is primarily generated during the unstable crack propagation stage;(4)A quantitative method employing a multi-factor approach combined with the brittleness index(BI)effectively characterizes shale fracturability.Evaluation results show that ScCO_(2)tDW has a more significant effect on shale fracturability,with fracturability indices of 0.833%and 1.180%following soaking at 15 MPa and 45 MPa,respectively.Higher immersion pressure correlates positively with increased shale fracturability.展开更多
Pd catalyst with high activity and selectivity for O_(2)reduction to H_(2)O_(2)is highly desirable.However,metallic Pd catalyst suffers from limited activity and selectivity in H_(2)O_(2)photosynthesis due to intrinsi...Pd catalyst with high activity and selectivity for O_(2)reduction to H_(2)O_(2)is highly desirable.However,metallic Pd catalyst suffers from limited activity and selectivity in H_(2)O_(2)photosynthesis due to intrinsically strong O_(2)adsorption at Pd atom sites.Herein,a strategy is proposed to modulate the electronic structure,aiming to weaken O_(2)adsorption and further enhance O_(2)-reduction selectivity through the creation of highly dispersed and electron-enriched Pd^(δ-)atom sites.To achieve this,a novel photochemical plating approach is employed to selectively grow vertical Bi nanosheets on the(010)facet of BiVO_(4).This process confines highly dispersed Pd atoms within the Bi nanosheets,forming a PdBi cocatalyst that significantly boosts H_(2)O_(2)photosynthesis.Notably,the optimized PdBi/BiVO_(4)photocatalyst achieves a high H_(2)O_(2)production concentration of 2246.43μmol L−1,with an apparent quantum efficiency(AQE)of 11.16%,realizing a 1.74-fold enhancement in activity compared to Pd/BiVO_(4)(1289.28μmol L^(−1)).Theoretical calculation and experimental results confirm that the vertical-growth Bi nanosheets induce the formation of well-dispersed and electron-enriched Pd^(δ−)atom sites.This accordingly increases the antibonding-orbital occupancy of Pd-O_(ads),thereby weakening O_(2)adsorption and ultimately facilitating selective O_(2)reduction for photocatalytic H_(2)O_(2)production.This rational design of Pd-based catalysts provides a promising strategy for modulating the electronic structure of active atoms to advance artificial photosynthesis.展开更多
基金supported by the Anhui Province Natural Science Foundation for Excellent Youth Scholars(2208085Y17)the University Synergy Innovation Program of Anhui Province(GXXT-2022-008+1 种基金GXXT-2021-022)the Anhui Key Lab of Metal Material and Processing Open Project.
文摘Doping modification is one of the most effective ways to optimize the thermoelectric properties of Bi_(2)Te_(3)-based alloys.P-type Bi_(2−x)Sb_(x)Te_(3) thermoelectric materials have been successfully prepared by direct Sb doping method.It can be found that doping Sb into Bi_(2)Te_(3) lattice array for Bi-site replacement facilitates the generation of Sb′Te anti-site defects.This anti-site defects can increase the hole concentration and optimize electrical transport properties of Bi_(2−x)Sb_(x)Te_(3) alloys.In addition,the point defects induced by mass and stress fluctuations and the Sb impurities produced during the sintering process can enhance the multi-scale phonon scattering and reduce the lattice thermal conductivity.As a result,the Bi_(0.47)Sb_(1.63)Te_(3) sample has a maximum thermoelectric figure of merit ZT of 1.04 at 350 K.It is worth noting that the bipolar effect of Bi_(2)Te_(3)-based alloys can be weakened with the increase of Sb content.The Bi_(0.44)Sb_(1.66)Te_(3) sample has a maximum average ZT value(0.93)in the temperature range of 300–500 K,indicating that direct doping of Sb can broaden the temperature range corresponding to the optimal ZT value.This work provides an idea for developing high-performance near room temperature thermoelectric materials with a wide temperature range.
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financially supported by National Key Research and Development Program of China(No.2022YFE0202400)the National Natural Science Foundation of China(No.22379103)+2 种基金Natural Science Foundation of Guangdong Province of China(No.2021A1515010388)the Science and Technology Projects of Suzhou City(No.SYC2022043)the Qing Lan Project of Jiangsu Province(2022)。
文摘The development of high-performance cathode materials is critical to the practical application of sodiumion batteries(SIBs).O3-type NaCrO_(2)(NCO)is one of the most competitive cathodes,but it suffers from rapid capacity decay caused by severe irreversible structural evolution.An Mg-Ti co-doped Na_(0.99)Cr_(0.95)Mg_(0.02)Ti_(0.03)O_(2)(NCO-MT)cathode material is designed and synthesized via a facile solid-state reaction to enhance the cyclability of NCO.A capacity retention of 71.6%after 2500 cycles with the capacity fade rate of 0.011%per cycle is achieved for NCO-MT at 5 C,which is attributed to the highly reversible crystal structure during cycling.Our findings offer a novel insight into the high-performance O3-type layered cathode materials for SIBs and are beneficial to promote the development of high-rate SIBs.
基金supported by the Fundamental Research Funds for the Central Universities(No.2019ZDPY04).
文摘In this work,the TiO_(2)/Sb_(2)S_(3) nanorod arrays(NRAs)were synthesized through a two-stage hydrothermal route for photoelectrochemical(PEC)water splitting.The effect of annealing treatment in Ar ambience on the PEC activity of TiO_(2)/Sb_(2)S_(3) composite sample was investigated by electrochemical impedance analysis,including Nyquist and Mott-Schottky(M-S)plots.It was demonstrated that vacuum annealing could crystallize Sb_(2)S_(3) component and change its color from red to black,leading to an increment of photocurrent density from 1.9 A/m^(2) to 4.25 A/m^(2) at 0 V versus saturated calomel electrode(VSCE).The enhanced PEC performance was mainly attributed to the improved visible light absorption.Moreover,annealing treatment facilitated retarding the electron-hole recombination occurred at the solid/liquid interfaces.Our work might provide a novel strategy for enhancing the PEC performance of a semiconductor electrode.
基金financially supported by the National Natural Science Foundation of China(No.51302061)Natural Science Foundation of Hebei Province(No.E2020201021 and E2023201019)+4 种基金Industry-University-Research Cooperation Major Projects of Shijiazhuang(No.241130477A)Research Innovation Team of College of Chemistry and Environmental Science of Hebei University(No.hxkytd2102)Industry-University-research Cooperation Project of Colleges and Universities in Hebei Province(No.CXZX2025016)Hebei Province Innovation Capability Enhancement Plan Project(No.22567620H)Bintuan Science and Technology Program(Nos.2020DB002 and 2022DB009)。
文摘Peroxymonosulfate(PMS)is commonly used in advanced oxidation processes to degrade organic pollutants in wastewater.In this work,to obtain better PMS activation efficiency,Bi_(4)O_(5)Br_(2)/BCZT(BBT)piezoelectric photocatalyst was designed.Abundant active radicals produced by BBT under visible light irradiation and ultrasonic vibration were used to activate PMS,thereby achieving rapid degradation of high concentration pollutants.With the introduction of BCZT,the catalyst has a strong internal electric field and three-dimensional lamellar structure,which promotes the separation and transfer of electrons and holes.It is worth noting that under optimal reaction conditions,the degradation rate of ARB reached 93%by BBT15 within 10 min.The catalytic experiment combined with the piezoelectric performance test results revealed the key role of piezoelectric photocatalytic reaction in PMS activation.This provides an important prospect for PMS to effectively deal with the degradation of high concentrations of organic pollutants.
基金financial support from the Science and Technology Innovation Program of Hunan Province(Grant No.2023RC1021)the National Natural Science Foundation of China(Grant No.52231012)+1 种基金the Natural Science Foundation of Hainan Province(Grant No.424QN213)the Scientific Research Foundation of Hainan University.
文摘The study of the effects of supercritical CO_(2)(ScCO_(2))under high temperature and high pressure on the mechanical properties and fracturing potential of shale holds significant implications for advancing our understanding of enhanced shale gas extraction and reservoir exploration and development.This study examines the influence of three fluids,i.e.ScCO_(2),deionized water(DW),and ScCO_(2)tDW,on the mechanical properties and fracturability of shale at immersion pressures of 15 MPa and 45 MPa,with a constant temperature of 100C.The key findings are as follows:(1)Uniaxial compressive strength(UCS)of shale decreased by 10.72%,11.95%,and 23.67%at 15 MPa,and by 42.40%,46.84%,and 51.65%at 45 MPa after immersion in ScCO_(2),DW,and ScCO_(2)tDW,respectively,with the most pronounced effect observed in ScCO_(2)tDW;(2)Microstructural analysis revealed that while ScCO_(2)and DW do not significantly alter the microstructure,immersion in ScCO_(2)tDW results in a more complex surface morphology;(3)Acoustic emission(AE)analysis indicates a reduction in stress for crack damage,with a decreased fractal dimension of AE signals in different fluids.AE energy is primarily generated during the unstable crack propagation stage;(4)A quantitative method employing a multi-factor approach combined with the brittleness index(BI)effectively characterizes shale fracturability.Evaluation results show that ScCO_(2)tDW has a more significant effect on shale fracturability,with fracturability indices of 0.833%and 1.180%following soaking at 15 MPa and 45 MPa,respectively.Higher immersion pressure correlates positively with increased shale fracturability.
基金supported by the National Natural Science Foundation of China(22178276,221760110,22178275)the Postdoctoral Fellowship Program of CPSF(GZC20240888)the Postdoctoral Project of Hubei Province(2024HBBHCXB053).
文摘Pd catalyst with high activity and selectivity for O_(2)reduction to H_(2)O_(2)is highly desirable.However,metallic Pd catalyst suffers from limited activity and selectivity in H_(2)O_(2)photosynthesis due to intrinsically strong O_(2)adsorption at Pd atom sites.Herein,a strategy is proposed to modulate the electronic structure,aiming to weaken O_(2)adsorption and further enhance O_(2)-reduction selectivity through the creation of highly dispersed and electron-enriched Pd^(δ-)atom sites.To achieve this,a novel photochemical plating approach is employed to selectively grow vertical Bi nanosheets on the(010)facet of BiVO_(4).This process confines highly dispersed Pd atoms within the Bi nanosheets,forming a PdBi cocatalyst that significantly boosts H_(2)O_(2)photosynthesis.Notably,the optimized PdBi/BiVO_(4)photocatalyst achieves a high H_(2)O_(2)production concentration of 2246.43μmol L−1,with an apparent quantum efficiency(AQE)of 11.16%,realizing a 1.74-fold enhancement in activity compared to Pd/BiVO_(4)(1289.28μmol L^(−1)).Theoretical calculation and experimental results confirm that the vertical-growth Bi nanosheets induce the formation of well-dispersed and electron-enriched Pd^(δ−)atom sites.This accordingly increases the antibonding-orbital occupancy of Pd-O_(ads),thereby weakening O_(2)adsorption and ultimately facilitating selective O_(2)reduction for photocatalytic H_(2)O_(2)production.This rational design of Pd-based catalysts provides a promising strategy for modulating the electronic structure of active atoms to advance artificial photosynthesis.
