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
Structural,optical and magnetic properties are reported for new synthesized perovskite materials.Ba_(0.3)La_(0.7)Ti_(0.3)Fe_(0.7)O_(3) and Ba_(0.1)La_(0.9)Ti_(0.1)Fe_(0.9)O_(3) compositions were prepared via solid sta...Structural,optical and magnetic properties are reported for new synthesized perovskite materials.Ba_(0.3)La_(0.7)Ti_(0.3)Fe_(0.7)O_(3) and Ba_(0.1)La_(0.9)Ti_(0.1)Fe_(0.9)O_(3) compositions were prepared via solid state reaction.X-ray analysis confirms that both compositions show feature of perovskite structure.Rietveld refinement method was used to confirm the phase formation and investigate the structure and space group.The study demonstrates the formation of orthorhombic structure with Pnma space group for Ba_(0.3)La_(0.7)Ti_(0.3)Fe_(0.7)O_(3) while the composition Ba_(0.1)La_(0.9)Ti_(0.1)Fe_(0.9)O_(3) structure adopts Pbnm symmetry.UV–vis spectroscopy measurements show very broad and intense UV–visible light absorption,the estimated band gap ranges between 2.07 and 2.15 eV.Magnetic measurements were carried out for the compositions Ba_(0.3)La_(0.7)Ti_(0.3)Fe_(0.7)O_(3) and Ba_(0.1)La_(0.9)Ti_(0.1)Fe_(0.9)O_(3).The hysteresis loops of both samples at 300 and 10 K show a strong ferromagnetic behavior.The temperature dependent magnetization at 0.05 T under field-cooled(FC)and zero field cooled(ZFC)modes shows magnetic frustration or spin glass-like behavior.展开更多
The integration of carbon dots(CDs)with graphitic carbon nitride(g-C_(3)N_(4))has emerged as a promising approach to enhance photocatalytic hydrogen(H_(2))evolution.Despite significant progress,critical challenges rem...The integration of carbon dots(CDs)with graphitic carbon nitride(g-C_(3)N_(4))has emerged as a promising approach to enhance photocatalytic hydrogen(H_(2))evolution.Despite significant progress,critical challenges remain in achieving broad visiblelight absorption and suppressing charge recombination.In this work,we developed a series of photocatalysts through in situ embedding of red-emissive CDs(R-CDs)into g-C_(3)N_(4)(RCN)with precisely controlled loading amounts.Systematic characterization revealed that the R-CDs incorporation simultaneously addresses two fundamental limitations:(1)extending the light absorption edge to 800 nm,and(2)acting as an electron acceptor,facilitating charge separation.The optimized RCN composite demonstrates exceptional H_(2)evolution activity(1.87 mmol·g^(-1)·h^(-1),wavelength(λ)≥420 nm),representing a 3.3-fold enhancement over pristine g-C_(3)N_(4).Remarkably,the apparent quantum efficiency(AQE)reaches 9.1% at 420 nm,while maintaining measurable activity beyond 475 nm,where unmodified g-C_(3)N_(4)shows negligible response.This study provides fundamental insights into band structure engineering and charge carrier management through rational design of CDs-modified semiconductor heterostructures.展开更多
Black polyimides(BPIs)have attracted increasing attention owing to their growing demand in optoelectronics.However,commonly used black polyimides doped with black fillers suffer from poor mechanical and electrical pro...Black polyimides(BPIs)have attracted increasing attention owing to their growing demand in optoelectronics.However,commonly used black polyimides doped with black fillers suffer from poor mechanical and electrical properties.To address these issues,a new diamine(2,5-bis(4′-amino-[1,1′-biphenyl]-4-yl)-3,4-bis(4-fluorophenyl)cyclopenta-2,4-dien-1-one,TPCPFPDA)bearing a tetraphenylcyclopentadienone(TPCP)moiety bonded with benzene and fluorine units was synthesized.The diamine was reacted with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)to yield a soluble intrinsic black polyimide(TPCPFPPI).Bonding fluorine(auxochrome group)and benzene units to TPCP can increase the conjugation ofπ-electrons systems and facilitate the movement of electron throughout the bigπbond,respectively.Owing to the structural features,the synthesized TPCPFPPI exhibited complete visible-light absorption with high blackness and opacity.Its cutoff wavelength(λ_(cut))and CIE(Commission Internationale de I′Eclairage)parameter L^(*)were 684 nm and 1.33,respectively.Moreover,TPCPFPPI displayed exceptional electrical,mechanical,and thermal properties as well as excellent solubility.A detailed theoretical calculation was conducted to gain better insight into the electronic properties of the TPCPFPPI.Results showed that the blackness of TPCPFPPI was chiefly attributed to the electron transition from highest occupied molecular orbital(HOMO)to lowest unoccupied molecular orbital(LUMO)in the diamines,where the charges primarily migrated from the aryl groups in the 2-and 5-positions to the cyclopentadienone center.The as-obtained intrinsic BPI(TPCPFPPI),exhibiting both high solubility and outstanding overall properties,has important applications in photo-electronics.展开更多
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MohammedⅥPolytechnic Universitythe Office Chérifien des Phosphates in the Moroccan Kingdom(OⅥCP group)University Hassan 1st for their support。
文摘Structural,optical and magnetic properties are reported for new synthesized perovskite materials.Ba_(0.3)La_(0.7)Ti_(0.3)Fe_(0.7)O_(3) and Ba_(0.1)La_(0.9)Ti_(0.1)Fe_(0.9)O_(3) compositions were prepared via solid state reaction.X-ray analysis confirms that both compositions show feature of perovskite structure.Rietveld refinement method was used to confirm the phase formation and investigate the structure and space group.The study demonstrates the formation of orthorhombic structure with Pnma space group for Ba_(0.3)La_(0.7)Ti_(0.3)Fe_(0.7)O_(3) while the composition Ba_(0.1)La_(0.9)Ti_(0.1)Fe_(0.9)O_(3) structure adopts Pbnm symmetry.UV–vis spectroscopy measurements show very broad and intense UV–visible light absorption,the estimated band gap ranges between 2.07 and 2.15 eV.Magnetic measurements were carried out for the compositions Ba_(0.3)La_(0.7)Ti_(0.3)Fe_(0.7)O_(3) and Ba_(0.1)La_(0.9)Ti_(0.1)Fe_(0.9)O_(3).The hysteresis loops of both samples at 300 and 10 K show a strong ferromagnetic behavior.The temperature dependent magnetization at 0.05 T under field-cooled(FC)and zero field cooled(ZFC)modes shows magnetic frustration or spin glass-like behavior.
基金financially supported by the National Key R&D Program of China(No.2023YFB3810800)the National Natural Science Foundation of China(Nos.22579008,22502012,22301013,and 22272003)+3 种基金Key Project of the National Natural Science Foundation of China(No.21936001)R&D Program of Beijing Municipal Education Commission(No.KZ20231000506)Beijing Outstanding Young Scientists Program(No.BJJWZYJH01201910005017)the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges Under Beijing Municipality(No.11000024T000003219982).
文摘The integration of carbon dots(CDs)with graphitic carbon nitride(g-C_(3)N_(4))has emerged as a promising approach to enhance photocatalytic hydrogen(H_(2))evolution.Despite significant progress,critical challenges remain in achieving broad visiblelight absorption and suppressing charge recombination.In this work,we developed a series of photocatalysts through in situ embedding of red-emissive CDs(R-CDs)into g-C_(3)N_(4)(RCN)with precisely controlled loading amounts.Systematic characterization revealed that the R-CDs incorporation simultaneously addresses two fundamental limitations:(1)extending the light absorption edge to 800 nm,and(2)acting as an electron acceptor,facilitating charge separation.The optimized RCN composite demonstrates exceptional H_(2)evolution activity(1.87 mmol·g^(-1)·h^(-1),wavelength(λ)≥420 nm),representing a 3.3-fold enhancement over pristine g-C_(3)N_(4).Remarkably,the apparent quantum efficiency(AQE)reaches 9.1% at 420 nm,while maintaining measurable activity beyond 475 nm,where unmodified g-C_(3)N_(4)shows negligible response.This study provides fundamental insights into band structure engineering and charge carrier management through rational design of CDs-modified semiconductor heterostructures.
基金supported by the National Natural Science Foundation of China (Grant Nos.51973055&52103004)the Natural Science Foundation of Hunan Province (Grant No.2021JJ50004)+1 种基金the Science Research Project of Hunan Provincial Department of Education (Grant No.21A0364)the Student Innovation and Entrepreneurship Training Program of Hunan Province (Grant No.S202211535096)。
文摘Black polyimides(BPIs)have attracted increasing attention owing to their growing demand in optoelectronics.However,commonly used black polyimides doped with black fillers suffer from poor mechanical and electrical properties.To address these issues,a new diamine(2,5-bis(4′-amino-[1,1′-biphenyl]-4-yl)-3,4-bis(4-fluorophenyl)cyclopenta-2,4-dien-1-one,TPCPFPDA)bearing a tetraphenylcyclopentadienone(TPCP)moiety bonded with benzene and fluorine units was synthesized.The diamine was reacted with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)to yield a soluble intrinsic black polyimide(TPCPFPPI).Bonding fluorine(auxochrome group)and benzene units to TPCP can increase the conjugation ofπ-electrons systems and facilitate the movement of electron throughout the bigπbond,respectively.Owing to the structural features,the synthesized TPCPFPPI exhibited complete visible-light absorption with high blackness and opacity.Its cutoff wavelength(λ_(cut))and CIE(Commission Internationale de I′Eclairage)parameter L^(*)were 684 nm and 1.33,respectively.Moreover,TPCPFPPI displayed exceptional electrical,mechanical,and thermal properties as well as excellent solubility.A detailed theoretical calculation was conducted to gain better insight into the electronic properties of the TPCPFPPI.Results showed that the blackness of TPCPFPPI was chiefly attributed to the electron transition from highest occupied molecular orbital(HOMO)to lowest unoccupied molecular orbital(LUMO)in the diamines,where the charges primarily migrated from the aryl groups in the 2-and 5-positions to the cyclopentadienone center.The as-obtained intrinsic BPI(TPCPFPPI),exhibiting both high solubility and outstanding overall properties,has important applications in photo-electronics.
基金financially supported by the National Key Research and Development Program of China(2019YFA0705900)funded by the Ministry of Science and Technology(MOST)the National Natural Science Foundation of China(52073281,22135007 and 21875244)the Natural Science Foundation of Jilin Province(20230101122JC)。
