The Y,F,and Ag tridoped TiO_(2)/SnO_(2)composite nanocrystalline film(YFAg–TS)with prominent photocatalytic performance was prepared by the modified sol–gel method and was characterized by utilizing X-ray diffractio...The Y,F,and Ag tridoped TiO_(2)/SnO_(2)composite nanocrystalline film(YFAg–TS)with prominent photocatalytic performance was prepared by the modified sol–gel method and was characterized by utilizing X-ray diffraction(XRD),differential thermal and thermogravimetric(DTA–TG)analysis,scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),Brunauer–Emmett–Teller(BET)method,ultraviolet–visible diffuse reflectance spectroscopy(UV–vis DRS),and photoluminescence(PL).The XRD and DTA–TG results expose that the YFAg–TS catalyst is a mixed phase consisting of anatase,rutile,and chlorargyrite,which is beneficial to improving the photocatalytic performance of TiO_(2).The SEM,TEM,and BET results disclose that the YFAg–TS film has smaller nanoparticles,higher specific surface area,and narrower pore size compared with pure TiO_(2)film.The XRD and TEM results exhibit that a part of yttrium can enter the TiO_(2)lattice to induce lattice distortion.The XPS results confirm the presence of Y^(3+)state in the YFAg–TS sample,and Y^(3+)ions can act as the trapping site of electrons to expedite the separation of electrons and holes.The UV–vis DRS results reveal that the YFAg–TS film has an obvious absorption edge shift and a narrower bandgap(2.70 eV)compared with pure TiO_(2)film.The PL results show that the YFAg–TS film has the highest photogenerated electrons and holes separation efficiency and charges transfer efficiency among all samples.The photocatalytic activity of the YFAg–TS was assessed by monitoring the degradation of methyl green and formaldehyde solution.The results manifest that the YFAg–TS film has high stability and excellent photocatalytic performance.The possible synergistic photocatalytic mechanism of YFAg–TS films has been discussed in this paper.展开更多
The bulk heterostructuring of TiO_(2)via codoping with nonmetals still holds possibilities for the potential development of a visible light photocatalyst and for overcoming the obstacles bracketed with metal ion subst...The bulk heterostructuring of TiO_(2)via codoping with nonmetals still holds possibilities for the potential development of a visible light photocatalyst and for overcoming the obstacles bracketed with metal ion substitution.In particular,tridoping of C-N-S into TiO_(2)was spotlighted with due consideration of its mesmerizing features like simultaneous and relatively low energy substitution of carbon,nitrogen and sulfur from the available precursors(thiourea,L-cystine and L-cysteine),stabilization of the anatase crystal structure,red shift in the band gap response towards the solar spectrum,cooperative interactions with these codopants,and the absence of any impure phase formation even at elevated temperature and with high doping density during the substitution process.Despite these flexibilities,accessible reports on C-N-S-TiO_(2)are not extensive and the discussions presented are far from the relevant aspects of the doping mechanism.With the intention of shedding light on the pros and cons of C-N-S-TiO_(2),this review is framed with the following viewpoints:(i)underscoring their beneficial effects in photocatalysis;(ii)underlining the doping mode of each dopant in the codoped system with respect to the reaction conditions;(iii)contradictions about the doping states of each dopant in the codoped system with reference to the previous literature;(iv)tentative discussion concepts like modifications of defect structures,dopant distribution,doping mode,mutual interferences among the dopants and crystallization kinetics in the course of codoping.The results emphasize that the codoping process involving carbon,nitrogen and sulfur is quite obfuscated as several doping modes are witnessed for each dopant,which are coupled to other factors like dopant diffusivity and solubility,extent of doping,dopant segregation at the surface,nature of the dopant precursor,unpredictable interactions of the dopant states,and interactive reactions between the dopant and titania precursor together with the annealing conditions.With critical analysis with reference to TiO_(2),it is envisaged that thiourea is the best functional precursor to attain diverse doping states for nitrogen,and cationic and anionic doping states for carbon and sulfur,together with the formation of adsorbed sulfate anions.Future research must shed light on the dopant-dopant and dopant-lattice interactions followed by their synergism at the structure-electronic level to uncover the doping mechanism in the codoped systems.展开更多
A simple sol-gel method was employed to prepare gadolinium, nitrogen and sulphur tridoped titania decorated on oxidised multiwalled carbon nanotubes（MWCNT/Gd,N,S-Ti O2）, using titanium（IV） butoxide and thiourea as...A simple sol-gel method was employed to prepare gadolinium, nitrogen and sulphur tridoped titania decorated on oxidised multiwalled carbon nanotubes（MWCNT/Gd,N,S-Ti O2）, using titanium（IV） butoxide and thiourea as titanium and nitrogen and sulphur source, respectively. Samples of varying gadolinium loadings（0.2%, 0.6%, 1.0% and3.0% Gd3＋） relative to titania were prepared to investigate the effect of gadolinium loading and the amounts of carbon nanotubes, nitrogen and sulphur were kept constant for all the samples. Furthermore, the prepared nanocomposites were evaluated for the degradation of naphthol blue black（NBB） in water under simulated solar light irradiation. Higher degradation efficiency（95.7%） was recorded for the MWCNT/Gd,N,S-Ti O2（0.6% Gd）nanocomposites. The higher photocatalytic activity is attributed to the combined effect of improved visible light absorption and charge separation due to the synergistic effect of Gd,MWCNTs, N, S and Ti O2. Total organic carbon（TOC） analysis revealed a higher degree of complete mineralisation of naphthol blue black（78.0% TOC removal） which minimises the possible formation of toxic degradation by-products such as the aromatic amines. The MWCNT/Gd,N,S-Ti O2（0.6% Gd） was fairly stable and could be re-used for five times,reaching a maximum degradation efficiency of 91.8% after the five cycles.展开更多
Local structure engineering is one of the most useful strategies for tunable down-shifting and upconversion emissions in halide double perovskites(DPs).However,the roles of the local structure,including local symmetry...Local structure engineering is one of the most useful strategies for tunable down-shifting and upconversion emissions in halide double perovskites(DPs).However,the roles of the local structure,including local symmetry,coordination structure,and active sites,in these DPs remain largely unexplored.Herein,we studied the local structure-correlated up/down-conversion luminescence in Yb^(3+)/Er^(3+)/Ho^(3+)co/tridoped Cs_(2)LiInCl_(6) with a unique local structure.展开更多
Highly sensitive and precise optical temperature measurements are pivotal across various fields,facilitating enhanced temperature regulation and monitoring.This study achieves an optically ultrahigh sensitivity temper...Highly sensitive and precise optical temperature measurements are pivotal across various fields,facilitating enhanced temperature regulation and monitoring.This study achieves an optically ultrahigh sensitivity temperature sensing system in Yb^(3+)/Nd^(3+)/Er^(3+)tridoped CaSc_(2)O_(4) by leveraging non-thermal coupling energy levels,specifically Er^(3+):^(4)F_(9/2) and Nd^(3+):^(4)F_(5/2).This accomplishment circumvents the sensitivity constraint imposed by the energy gap.The maximum absolute and relative sensitivity of the optical thermometer peaks at 13.92%K^(-1) and 4.61%K^(-1) respectively,surpassing the values from the majority of analogous optical thermometers.Furthermore,it also exhibits exceptional temperature resolution,maintaining values below 0.03 K throughout the entire testing temperature range.Simultaneously,the temperature sensing properties reliant on the thermally coupled Er^(3+):^(2)H_(11/2)/^(4)S_(3/2) states are explored in detail,revealing the maximum absolute and relative sensitivity for temperature measurement of 0.37%K^(-1) and 1.53%K^(-1),respectively.In the validation experiment,both of the optical thermometers show accurate temperature measurement capability.Additionally,the penetration depth in the biological tissues is 8 mm for the green and red light of Er^(3+)and 10 mm for the near-infrared emission of Nd^(3+).All of these studies collectively demonstrate the potential of CaSc2O_(4):Yb^(3+)/Nd^(3+)/Er^(3+)for achieving ultrasensitive temperature sensing and application in the deep biological tissues.展开更多
基金Project supported by the Natural Science Foundation of Shandong Province(ZR2016BM30)。
文摘The Y,F,and Ag tridoped TiO_(2)/SnO_(2)composite nanocrystalline film(YFAg–TS)with prominent photocatalytic performance was prepared by the modified sol–gel method and was characterized by utilizing X-ray diffraction(XRD),differential thermal and thermogravimetric(DTA–TG)analysis,scanning electron microscopy(SEM),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS),Brunauer–Emmett–Teller(BET)method,ultraviolet–visible diffuse reflectance spectroscopy(UV–vis DRS),and photoluminescence(PL).The XRD and DTA–TG results expose that the YFAg–TS catalyst is a mixed phase consisting of anatase,rutile,and chlorargyrite,which is beneficial to improving the photocatalytic performance of TiO_(2).The SEM,TEM,and BET results disclose that the YFAg–TS film has smaller nanoparticles,higher specific surface area,and narrower pore size compared with pure TiO_(2)film.The XRD and TEM results exhibit that a part of yttrium can enter the TiO_(2)lattice to induce lattice distortion.The XPS results confirm the presence of Y^(3+)state in the YFAg–TS sample,and Y^(3+)ions can act as the trapping site of electrons to expedite the separation of electrons and holes.The UV–vis DRS results reveal that the YFAg–TS film has an obvious absorption edge shift and a narrower bandgap(2.70 eV)compared with pure TiO_(2)film.The PL results show that the YFAg–TS film has the highest photogenerated electrons and holes separation efficiency and charges transfer efficiency among all samples.The photocatalytic activity of the YFAg–TS was assessed by monitoring the degradation of methyl green and formaldehyde solution.The results manifest that the YFAg–TS film has high stability and excellent photocatalytic performance.The possible synergistic photocatalytic mechanism of YFAg–TS films has been discussed in this paper.
文摘The bulk heterostructuring of TiO_(2)via codoping with nonmetals still holds possibilities for the potential development of a visible light photocatalyst and for overcoming the obstacles bracketed with metal ion substitution.In particular,tridoping of C-N-S into TiO_(2)was spotlighted with due consideration of its mesmerizing features like simultaneous and relatively low energy substitution of carbon,nitrogen and sulfur from the available precursors(thiourea,L-cystine and L-cysteine),stabilization of the anatase crystal structure,red shift in the band gap response towards the solar spectrum,cooperative interactions with these codopants,and the absence of any impure phase formation even at elevated temperature and with high doping density during the substitution process.Despite these flexibilities,accessible reports on C-N-S-TiO_(2)are not extensive and the discussions presented are far from the relevant aspects of the doping mechanism.With the intention of shedding light on the pros and cons of C-N-S-TiO_(2),this review is framed with the following viewpoints:(i)underscoring their beneficial effects in photocatalysis;(ii)underlining the doping mode of each dopant in the codoped system with respect to the reaction conditions;(iii)contradictions about the doping states of each dopant in the codoped system with reference to the previous literature;(iv)tentative discussion concepts like modifications of defect structures,dopant distribution,doping mode,mutual interferences among the dopants and crystallization kinetics in the course of codoping.The results emphasize that the codoping process involving carbon,nitrogen and sulfur is quite obfuscated as several doping modes are witnessed for each dopant,which are coupled to other factors like dopant diffusivity and solubility,extent of doping,dopant segregation at the surface,nature of the dopant precursor,unpredictable interactions of the dopant states,and interactive reactions between the dopant and titania precursor together with the annealing conditions.With critical analysis with reference to TiO_(2),it is envisaged that thiourea is the best functional precursor to attain diverse doping states for nitrogen,and cationic and anionic doping states for carbon and sulfur,together with the formation of adsorbed sulfate anions.Future research must shed light on the dopant-dopant and dopant-lattice interactions followed by their synergism at the structure-electronic level to uncover the doping mechanism in the codoped systems.
基金Funding from the University of Johannesburg and DST-NRF Centre of Excellence in Strong Materials is highly appreciated
文摘A simple sol-gel method was employed to prepare gadolinium, nitrogen and sulphur tridoped titania decorated on oxidised multiwalled carbon nanotubes（MWCNT/Gd,N,S-Ti O2）, using titanium（IV） butoxide and thiourea as titanium and nitrogen and sulphur source, respectively. Samples of varying gadolinium loadings（0.2%, 0.6%, 1.0% and3.0% Gd3＋） relative to titania were prepared to investigate the effect of gadolinium loading and the amounts of carbon nanotubes, nitrogen and sulphur were kept constant for all the samples. Furthermore, the prepared nanocomposites were evaluated for the degradation of naphthol blue black（NBB） in water under simulated solar light irradiation. Higher degradation efficiency（95.7%） was recorded for the MWCNT/Gd,N,S-Ti O2（0.6% Gd）nanocomposites. The higher photocatalytic activity is attributed to the combined effect of improved visible light absorption and charge separation due to the synergistic effect of Gd,MWCNTs, N, S and Ti O2. Total organic carbon（TOC） analysis revealed a higher degree of complete mineralisation of naphthol blue black（78.0% TOC removal） which minimises the possible formation of toxic degradation by-products such as the aromatic amines. The MWCNT/Gd,N,S-Ti O2（0.6% Gd） was fairly stable and could be re-used for five times,reaching a maximum degradation efficiency of 91.8% after the five cycles.
基金supported by the National Natural Science Foundation of China-Yunnan Joint Fund(U1902222)the National Natural Science Foundation of China(12064021 and 51862020)+1 种基金the Foundation of Yunnan Province(202001AT070037,202101AT070104 and 202101AT070097)Yunnan Major Scientific and Technological Projects(grant no.202202AG050016).
文摘Local structure engineering is one of the most useful strategies for tunable down-shifting and upconversion emissions in halide double perovskites(DPs).However,the roles of the local structure,including local symmetry,coordination structure,and active sites,in these DPs remain largely unexplored.Herein,we studied the local structure-correlated up/down-conversion luminescence in Yb^(3+)/Er^(3+)/Ho^(3+)co/tridoped Cs_(2)LiInCl_(6) with a unique local structure.
基金financially supported by the National Natural Science Foundation of China(11704054,12004062,and 52104392)Natural Science Foundation of Chongqing(CSTB2022NSCQ-MSX0366 and csct2021jcyj-msxmX0578)Science and Technology Research Program of Chongqing Municipal Education Commission(KJZD-K202300612,KJQN202100615,and KJQN202100639).
文摘Highly sensitive and precise optical temperature measurements are pivotal across various fields,facilitating enhanced temperature regulation and monitoring.This study achieves an optically ultrahigh sensitivity temperature sensing system in Yb^(3+)/Nd^(3+)/Er^(3+)tridoped CaSc_(2)O_(4) by leveraging non-thermal coupling energy levels,specifically Er^(3+):^(4)F_(9/2) and Nd^(3+):^(4)F_(5/2).This accomplishment circumvents the sensitivity constraint imposed by the energy gap.The maximum absolute and relative sensitivity of the optical thermometer peaks at 13.92%K^(-1) and 4.61%K^(-1) respectively,surpassing the values from the majority of analogous optical thermometers.Furthermore,it also exhibits exceptional temperature resolution,maintaining values below 0.03 K throughout the entire testing temperature range.Simultaneously,the temperature sensing properties reliant on the thermally coupled Er^(3+):^(2)H_(11/2)/^(4)S_(3/2) states are explored in detail,revealing the maximum absolute and relative sensitivity for temperature measurement of 0.37%K^(-1) and 1.53%K^(-1),respectively.In the validation experiment,both of the optical thermometers show accurate temperature measurement capability.Additionally,the penetration depth in the biological tissues is 8 mm for the green and red light of Er^(3+)and 10 mm for the near-infrared emission of Nd^(3+).All of these studies collectively demonstrate the potential of CaSc2O_(4):Yb^(3+)/Nd^(3+)/Er^(3+)for achieving ultrasensitive temperature sensing and application in the deep biological tissues.
