Photonic crystal sensing is an emerging technique that directly indicates the physicochemical changes with the change of structural color.However,there are still challenges in material synthesis,ease of use,and reprod...Photonic crystal sensing is an emerging technique that directly indicates the physicochemical changes with the change of structural color.However,there are still challenges in material synthesis,ease of use,and reproducibility of detection for traditional photonic crystal(PC)sensors.Here,a phenylboronic-acid functionalized SiO2 liquid photonic crystal(PBA-LPC)reagent was developed for reliable detection of glucose concentration.It is convenient to prepare/use the LPC reagent because people only need to mix the responsive substance or the analyte solution with the LPCs in synthesis/detection.The sensing was based on the mechanism that the mixing of PBA-LPC reagent with glucose could release H+cations from PBA,which inhibited the deprotonation of the silanol group,weakened the particle surface charge,and blue-shifted the reflection of LPC.The PBA LPC reagents responded to the glucose in different concentration ranges depending on the dosage of PBA,which ensured both a broad range detection and an accurate detection within a specific range.Meanwhile,it reported reproducible results due to the precise introduction of PBA and its sufficient interaction with glucose.Furthermore,the PBA-LPC reagent showed a selective response to glucose and good anti-interference capability against the presence of NaCl,CaSO_(4),KH_(2)PO_(4),and Vitamin C.Due to these properties,the PBA-LPC reagent could serve as a new material for blood sugar tests and it also demonstrated the great potential of LPCs in sensing applications.展开更多
As an apex predator the Amur tiger(Panthera tigris altaica)could play a pivotal role in maintaining the integrity of forest ecosystems in Northeast Asia.Due to habitat loss and harvest over the past century,tige...As an apex predator the Amur tiger(Panthera tigris altaica)could play a pivotal role in maintaining the integrity of forest ecosystems in Northeast Asia.Due to habitat loss and harvest over the past century,tigers rapidly declined in China and are now restricted to the Russian Far East and bordering habitat in nearby China.To facilitate restoration of the tiger in its historical range,reliable estimates of population size are essential to assess effectiveness of conservation interventions.Here we used camera trap data collected in Hunchun National Nature Reserve from April to June 2013 and 2014 to estimate tiger density and abundance using both maximum likelihood and Bayesian spatially explicit capture-recapture(SECR)methods.A minimum of 8 individuals were detected in both sample periods and the documentation of marking behavior and reproduction suggests the presence of a resident population.Using Bayesian SECR modeling within the 11400 km2 state space,density estimates were 0.33 and 0.40 individuals/100 km^(2) in 2013 and 2014,respectively,corresponding to an estimated abundance of 38 and 45 animals for this transboundary Sino-Russian population.In a maximum likelihood framework,we estimated densities of 0.30 and 0.24 individuals/100 km^(2) corresponding to abundances of 34 and 27,in 2013 and 2014,respectively.These density estimates are comparable to other published estimates for resident Amur tiger populations in the Russian Far East.This study reveals promising signs of tiger recovery in Northeast China,and demonstrates the importance of connectivity between the Russian and Chinese populations for recovering tigers in Northeast China.展开更多
The continuation of the isolated Amur tiger(Panthera tigris altaica)population living along the China-Russia border is facing serious challenges due to factors such as its small size(including 38 individuals)and canin...The continuation of the isolated Amur tiger(Panthera tigris altaica)population living along the China-Russia border is facing serious challenges due to factors such as its small size(including 38 individuals)and canine distemper virus(CDV).We use a population viability analysis metamodel,which consists of a traditional individual-based demographic model linked to an epidemiological model,to assess options for controlling the impact of negative factors through domestic dog management in protected areas,increasing connectivity to the neighboring large population(including more than 400 individuals),and habitat expansion.Without intervention,under inbreeding depression of 3.14,6.29,and 12.26 lethal equivalents,our metamodel predicted the extinction within 100 years is 64.4%,90.6%,and 99.8%,respectively.In addition,the simulation results showed that dog management or habitat expansion independently will not ensure tiger population viability for the next 100 years,and connectivity to the neighboring population would only keep the population size from rapidly declining.However,when the above three conservation scenarios are combined,even at the highest level of 12.26 lethal equivalents inbreeding depression,population size will not decline and the probability of extinction will be<5.8%.Our findings highlight that protecting the Amur tiger necessitates a multifaceted synergistic effort.Our key management recommendations for this population underline the importance of reducing CDV threats and expanding tiger occupancy to its former range in China,but re-establishing habitat connectivity to the neighboring population is an important long-term objective.展开更多
Carbon-based materials with tunable properties have emerged as promising candidates to replace Pt-based catalysts for accelerating oxygen reduction reaction(ORR)in fuel cells or metal-air batteries.In this work,we con...Carbon-based materials with tunable properties have emerged as promising candidates to replace Pt-based catalysts for accelerating oxygen reduction reaction(ORR)in fuel cells or metal-air batteries.In this work,we constructed a carbon hybrid which consists of one-dimensional(1D)carbon nanotubes and flake-like carbons by pyrolysis of leaf-like metal-organic frameworks.The optimal hybrid electrocatalyst of Fe_(7%)-L-CNT-900 possesses the desired features for ORR,including active Fe species,high degree of graphitization,large specific surface area,and hierarchical porous structures.Consequently,Fe_(7%)-L-CNT900 performs a high electrocatalytic activity for ORR with a half-wave potential of 0.88 V,which is comparable to that of Pt/C(20 wt.%).This strategy provides an insight into the investigation of highly efficient and low-cost composite electrocatalyst for oxygen reduction reaction.展开更多
This paper explores the capability of the“surface-protected etching”process for the creation of rattle-type SiO_(2)@void@SiO_(2) colloidal structures featuring a mesoporous silica shell and a mesoporous movable sili...This paper explores the capability of the“surface-protected etching”process for the creation of rattle-type SiO_(2)@void@SiO_(2) colloidal structures featuring a mesoporous silica shell and a mesoporous movable silica core.The surface-protected etching process involves stabilization of the particle surface using a polymer ligand,and then selective etching of the interior to form hollow structures.In this paper,this strategy has been extended to the formation of rattle-like structures by etching SiO_(2)@SiO_(2) core shell particles which are synthesized by a two-step sol gel process.The key is to introduce a protecting polymer of polyvinylpyrrolidone(PVP)to the surface of both core and shell in order to tailor their relative stability against chemical etching.Upon reacting with NaOH,the outer layer silica becomes a hollow shell as only the surface layer is protected by PVP and the interior is removed,while the core remains its original size thanks to the protection of PVP on its surface.This process can be carried out at room temperature without the need of additional templates or complicated heterogeneous coating procedures.The etching process also results in the rattle-type colloids having mesoscale pores with two distinct average sizes.In our demonstration of a model drug delivery process,such mesoporous structures show an interesting two-step elution profile which is believed to be related to the unique porous rattle structures.展开更多
The North Chinese leopard(Panthera pardus japonensis),the least-known big cat,disappeared in most historical range for decades,following the development of modern civilization.Unfortunately,we have scarce knowledge ab...The North Chinese leopard(Panthera pardus japonensis),the least-known big cat,disappeared in most historical range for decades,following the development of modern civilization.Unfortunately,we have scarce knowledge about the status of this big cat so far,apart from anecdotal reports.In this study,we investigated density,distribution,and habitat use of the leopard,the apex predator,in a complex forest landscape in the Loess Plateau.We used a camera-trapping network to obtain population estimates for leopards over 2 years through spatially explicit capture-recapture models.Our results,based on maximum likelihood and Bayesian/MCMC methods,reveal that the largest wild population of the leopard was found widely distributed in remnant forests in central Loess plateau.The population is increasing in our study area,and the density of leopards(1.70(SE=0.48)−2.40(SE=0.67)/100 km^(2))is higher than other areas of China.According to the analysis of 2 seasonal occupancy models,prey species drive partially the leopard habitat use,predicting that the big cat thrives from the recovery of prey community.However,human disturbances,especially oil wells,seem to have negative impacts on the habitat use of leopards.Specifically,it is necessary to have joint efforts by the government and researchers to improve human disturbances management and prey species population density,as well as strengthen the investment in research on the North Chinese leopard,which could all further strengthen protection ability and ensure the long-term survival of this species.展开更多
Mesoporous g-C3N4 nanorods （NRs） are synthesized through the nano-confined thermal condensation of cyanamide in silica nanotubes （NTs） with porous shells.The gas bubbles retained during condensation and the limite...Mesoporous g-C3N4 nanorods （NRs） are synthesized through the nano-confined thermal condensation of cyanamide in silica nanotubes （NTs） with porous shells.The gas bubbles retained during condensation and the limited cyanamide precursor inside the silica NTs lead to the formation of mesoporous g-C3N4.This nano-confined reaction is an alternative method to the traditional templating process for the synthesis of mesoporous materials.The as-prepared mesoporous g-C3N4 NRs exhibit remarkably improved photocatalytic activity and high stability in water splitting and degradation of Rhodamine B compared with bulk g-C3N4.展开更多
Highly dispersed Ni catalyst and alkaline promoters supported by mesoporous SiO_(2)nanospheres were synthesized and applied as an active and stable catalyst for dry reforming of methane(DRM).The as-prepared Ni/MgO-mSi...Highly dispersed Ni catalyst and alkaline promoters supported by mesoporous SiO_(2)nanospheres were synthesized and applied as an active and stable catalyst for dry reforming of methane(DRM).The as-prepared Ni/MgO-mSiO_(2)catalyst showed stable conversions of CH4 and CO_(2)around 82%and 85%in 120 h of DRM reaction,which was superior in performance compared to similar catalysts in literatures.Based on the transmission electron microscope(TEM)images,energy-dispersive spectroscopy(EDS),CO-pulse adsorption,temperature programmed reduction of the oxidized catalysts by hydrogen(H_(2)-TPR),X-ray photoelectron spectroscopy(XPS),temperature-programmed desorption of CO_(2)(CO_(2)-TPD),and thermal gravitational analysis(TGA),the promotion effect of MgO on the Ni catalyst was systematically studied.The introduction of Mg^(2+)in synthesis enhanced the interaction between Ni^(2+)and mSiO_(2),which led to a high dispersion of active centers and a strong“metal–support”interactions to inhibit the sintering and deactivation of Ni at reaction temperatures.On the other hand,Ni and MgO nanoparticles formed adjacently on mSiO_(2),where the“Ni-MgO”interface not only improved the Ni0 distribution and promoted the cracking of CH_(4)but also promoted the activation of CO_(2)and the elimination of carbon deposits.A high and stable conversion of CH4 and CO_(2)were then achieved through the synergistic effect of Ni catalyst,MgO promoter,and mSiO_(2)support.展开更多
Photonic crystal(PC)patterns have shown wide applications in optical devices,information encryption,anticounterfeiting,etc.Unfortunately,it is stll a great challenge to reconfigure the PC patterns once fabricated.Here...Photonic crystal(PC)patterns have shown wide applications in optical devices,information encryption,anticounterfeiting,etc.Unfortunately,it is stll a great challenge to reconfigure the PC patterns once fabricated.Herein,a new strategy is presented to reconfigure self-recordable PC patterns by printing local patterns into the chameleon-inspired PC papers using the phase change material(PCM)as ink and then erasing the patterns in ethanol.Multicolor and high-resolution(25 and 75μm for dot and lines,respectively)patterns can be eficiently and repeatedly reconfigured.In addition,the photonic patterns based on the PC paper and PCM combinations are gifted with mechanochromic characteristics and can show programmable and reversible color change under pressure.The high melting point of the ink,nonclosely packed structures of the PC paper,and the similar solubility parameter of PC paper,PCM,and ethanol are the keys for all these characteristics.This work offers a simple,flexible,efficient way to reconfigure PC patterns with mechanochromic properties and could open up exciting applications for novel hand-operation-based anticounterfeiting and opticaldevices.展开更多
Expensive instruments and complicated data processing are often required to discriminate solvents with similar structures and properties.Colorimetric sensors with high selectivity,low cost,and good portability are hig...Expensive instruments and complicated data processing are often required to discriminate solvents with similar structures and properties.Colorimetric sensors with high selectivity,low cost,and good portability are highly desirable to simplify such detection tasks.Herein,we report the fabrication of a photonic crystal sensor based on the self-assembled resorcinol formaldehyde(RF)hollow spheres to realize colorimetric sensing of polar solvents,including homologs and isomers based on the saturated diffusion time.The diffusion of solvent molecules through the photonic crystal film exhibits a unique three-step diffusion profile accompanied by a dynamic color change,as determined by the physicochemical properties of the solvent molecules and their interactions with the polymer shells,making it possible to accurately identify the solvent type based on the dynamic reflection spectra or visual perception.With its superior selectivity and sensitivity,this single-component colorimetric sensor represents a straightforward tool for convenient solvent detection and identification.展开更多
The catalytic performance of TiO_(2)in photoreduction of CO_(2)is limited by its weak absorption in the visible range.In this work,a photonic crystal supported blue TiO_(2)photocatalyst(BTPC)was prepared to demonstrat...The catalytic performance of TiO_(2)in photoreduction of CO_(2)is limited by its weak absorption in the visible range.In this work,a photonic crystal supported blue TiO_(2)photocatalyst(BTPC)was prepared to demonstrate a 5-6 times higher activity and improved CH_(4)selectivity compared to the BT catalysts deposited on quartz plate.By investigating the influence of the reflection intensity and wavelength of PC support,the superior catalytic performance was found to be originated from the enhanced light absorption of BT and the increased surface electron density brought by the PC support.Based on the study of BT loading on support,multilayer BTPC catalyst was designed to take the most advantage of the transmitted light and achieve a higher conversion of CO_(2)in the unit area of irradiation.展开更多
基金This work is granted by the National Natural Science Foundation of China(Nos.22172054 and 22472061).
文摘Photonic crystal sensing is an emerging technique that directly indicates the physicochemical changes with the change of structural color.However,there are still challenges in material synthesis,ease of use,and reproducibility of detection for traditional photonic crystal(PC)sensors.Here,a phenylboronic-acid functionalized SiO2 liquid photonic crystal(PBA-LPC)reagent was developed for reliable detection of glucose concentration.It is convenient to prepare/use the LPC reagent because people only need to mix the responsive substance or the analyte solution with the LPCs in synthesis/detection.The sensing was based on the mechanism that the mixing of PBA-LPC reagent with glucose could release H+cations from PBA,which inhibited the deprotonation of the silanol group,weakened the particle surface charge,and blue-shifted the reflection of LPC.The PBA LPC reagents responded to the glucose in different concentration ranges depending on the dosage of PBA,which ensured both a broad range detection and an accurate detection within a specific range.Meanwhile,it reported reproducible results due to the precise introduction of PBA and its sufficient interaction with glucose.Furthermore,the PBA-LPC reagent showed a selective response to glucose and good anti-interference capability against the presence of NaCl,CaSO_(4),KH_(2)PO_(4),and Vitamin C.Due to these properties,the PBA-LPC reagent could serve as a new material for blood sugar tests and it also demonstrated the great potential of LPCs in sensing applications.
基金supported by grants from the Natural Science Foundation of China(31270567,31210103911,31421063,31200410 and 31470566)the National Scientific and Technical Foundation Project of China(2012FY112000).
文摘As an apex predator the Amur tiger(Panthera tigris altaica)could play a pivotal role in maintaining the integrity of forest ecosystems in Northeast Asia.Due to habitat loss and harvest over the past century,tigers rapidly declined in China and are now restricted to the Russian Far East and bordering habitat in nearby China.To facilitate restoration of the tiger in its historical range,reliable estimates of population size are essential to assess effectiveness of conservation interventions.Here we used camera trap data collected in Hunchun National Nature Reserve from April to June 2013 and 2014 to estimate tiger density and abundance using both maximum likelihood and Bayesian spatially explicit capture-recapture(SECR)methods.A minimum of 8 individuals were detected in both sample periods and the documentation of marking behavior and reproduction suggests the presence of a resident population.Using Bayesian SECR modeling within the 11400 km2 state space,density estimates were 0.33 and 0.40 individuals/100 km^(2) in 2013 and 2014,respectively,corresponding to an estimated abundance of 38 and 45 animals for this transboundary Sino-Russian population.In a maximum likelihood framework,we estimated densities of 0.30 and 0.24 individuals/100 km^(2) corresponding to abundances of 34 and 27,in 2013 and 2014,respectively.These density estimates are comparable to other published estimates for resident Amur tiger populations in the Russian Far East.This study reveals promising signs of tiger recovery in Northeast China,and demonstrates the importance of connectivity between the Russian and Chinese populations for recovering tigers in Northeast China.
基金This work was supported by the National Natural Science Foundation of China(31971539)the National Science and Technology Basic Resources Survey Program of China(2019FY101700)a scholarship from the China Scholarship Council(202106040062).
文摘The continuation of the isolated Amur tiger(Panthera tigris altaica)population living along the China-Russia border is facing serious challenges due to factors such as its small size(including 38 individuals)and canine distemper virus(CDV).We use a population viability analysis metamodel,which consists of a traditional individual-based demographic model linked to an epidemiological model,to assess options for controlling the impact of negative factors through domestic dog management in protected areas,increasing connectivity to the neighboring large population(including more than 400 individuals),and habitat expansion.Without intervention,under inbreeding depression of 3.14,6.29,and 12.26 lethal equivalents,our metamodel predicted the extinction within 100 years is 64.4%,90.6%,and 99.8%,respectively.In addition,the simulation results showed that dog management or habitat expansion independently will not ensure tiger population viability for the next 100 years,and connectivity to the neighboring population would only keep the population size from rapidly declining.However,when the above three conservation scenarios are combined,even at the highest level of 12.26 lethal equivalents inbreeding depression,population size will not decline and the probability of extinction will be<5.8%.Our findings highlight that protecting the Amur tiger necessitates a multifaceted synergistic effort.Our key management recommendations for this population underline the importance of reducing CDV threats and expanding tiger occupancy to its former range in China,but re-establishing habitat connectivity to the neighboring population is an important long-term objective.
基金The authors acknowledge the financial support from the National Natural Science Foundation of China(No.22005099)sponsored by Shanghai Pujiang Program(No.19PJ1402500)and Fundamental Research Funds for the Central Universities.
文摘Carbon-based materials with tunable properties have emerged as promising candidates to replace Pt-based catalysts for accelerating oxygen reduction reaction(ORR)in fuel cells or metal-air batteries.In this work,we constructed a carbon hybrid which consists of one-dimensional(1D)carbon nanotubes and flake-like carbons by pyrolysis of leaf-like metal-organic frameworks.The optimal hybrid electrocatalyst of Fe_(7%)-L-CNT-900 possesses the desired features for ORR,including active Fe species,high degree of graphitization,large specific surface area,and hierarchical porous structures.Consequently,Fe_(7%)-L-CNT900 performs a high electrocatalytic activity for ORR with a half-wave potential of 0.88 V,which is comparable to that of Pt/C(20 wt.%).This strategy provides an insight into the investigation of highly efficient and low-cost composite electrocatalyst for oxygen reduction reaction.
文摘This paper explores the capability of the“surface-protected etching”process for the creation of rattle-type SiO_(2)@void@SiO_(2) colloidal structures featuring a mesoporous silica shell and a mesoporous movable silica core.The surface-protected etching process involves stabilization of the particle surface using a polymer ligand,and then selective etching of the interior to form hollow structures.In this paper,this strategy has been extended to the formation of rattle-like structures by etching SiO_(2)@SiO_(2) core shell particles which are synthesized by a two-step sol gel process.The key is to introduce a protecting polymer of polyvinylpyrrolidone(PVP)to the surface of both core and shell in order to tailor their relative stability against chemical etching.Upon reacting with NaOH,the outer layer silica becomes a hollow shell as only the surface layer is protected by PVP and the interior is removed,while the core remains its original size thanks to the protection of PVP on its surface.This process can be carried out at room temperature without the need of additional templates or complicated heterogeneous coating procedures.The etching process also results in the rattle-type colloids having mesoscale pores with two distinct average sizes.In our demonstration of a model drug delivery process,such mesoporous structures show an interesting two-step elution profile which is believed to be related to the unique porous rattle structures.
基金supported by grant from the National Natural Sci-ence Foundation of China(31670537,31200410)the National Scientific and Technical Foundation Project of China(2012FY112000)Cyrus Tang Foundation(2016),and the Doctoral Fund of Ministry of Education of China(2019M653714).
文摘The North Chinese leopard(Panthera pardus japonensis),the least-known big cat,disappeared in most historical range for decades,following the development of modern civilization.Unfortunately,we have scarce knowledge about the status of this big cat so far,apart from anecdotal reports.In this study,we investigated density,distribution,and habitat use of the leopard,the apex predator,in a complex forest landscape in the Loess Plateau.We used a camera-trapping network to obtain population estimates for leopards over 2 years through spatially explicit capture-recapture models.Our results,based on maximum likelihood and Bayesian/MCMC methods,reveal that the largest wild population of the leopard was found widely distributed in remnant forests in central Loess plateau.The population is increasing in our study area,and the density of leopards(1.70(SE=0.48)−2.40(SE=0.67)/100 km^(2))is higher than other areas of China.According to the analysis of 2 seasonal occupancy models,prey species drive partially the leopard habitat use,predicting that the big cat thrives from the recovery of prey community.However,human disturbances,especially oil wells,seem to have negative impacts on the habitat use of leopards.Specifically,it is necessary to have joint efforts by the government and researchers to improve human disturbances management and prey species population density,as well as strengthen the investment in research on the North Chinese leopard,which could all further strengthen protection ability and ensure the long-term survival of this species.
基金This work is supported by National Natural Science Foundation of China （Nos. 21671067 and 21471058）, the National Key Research and Development Program of China （No. 2016YFB0701103）, National Program for Support of Top-notch Young Professionals and Shuguang Program （No. 15SG21）.
文摘Mesoporous g-C3N4 nanorods （NRs） are synthesized through the nano-confined thermal condensation of cyanamide in silica nanotubes （NTs） with porous shells.The gas bubbles retained during condensation and the limited cyanamide precursor inside the silica NTs lead to the formation of mesoporous g-C3N4.This nano-confined reaction is an alternative method to the traditional templating process for the synthesis of mesoporous materials.The as-prepared mesoporous g-C3N4 NRs exhibit remarkably improved photocatalytic activity and high stability in water splitting and degradation of Rhodamine B compared with bulk g-C3N4.
基金supported by SINOPEC Research Institute of Petroleum Processing,the National Key Research and Development Program of China(No.2016YFB0701103)the National Natural Science Foundation of China(Nos.21972046 and 22172054).
文摘Highly dispersed Ni catalyst and alkaline promoters supported by mesoporous SiO_(2)nanospheres were synthesized and applied as an active and stable catalyst for dry reforming of methane(DRM).The as-prepared Ni/MgO-mSiO_(2)catalyst showed stable conversions of CH4 and CO_(2)around 82%and 85%in 120 h of DRM reaction,which was superior in performance compared to similar catalysts in literatures.Based on the transmission electron microscope(TEM)images,energy-dispersive spectroscopy(EDS),CO-pulse adsorption,temperature programmed reduction of the oxidized catalysts by hydrogen(H_(2)-TPR),X-ray photoelectron spectroscopy(XPS),temperature-programmed desorption of CO_(2)(CO_(2)-TPD),and thermal gravitational analysis(TGA),the promotion effect of MgO on the Ni catalyst was systematically studied.The introduction of Mg^(2+)in synthesis enhanced the interaction between Ni^(2+)and mSiO_(2),which led to a high dispersion of active centers and a strong“metal–support”interactions to inhibit the sintering and deactivation of Ni at reaction temperatures.On the other hand,Ni and MgO nanoparticles formed adjacently on mSiO_(2),where the“Ni-MgO”interface not only improved the Ni0 distribution and promoted the cracking of CH_(4)but also promoted the activation of CO_(2)and the elimination of carbon deposits.A high and stable conversion of CH4 and CO_(2)were then achieved through the synergistic effect of Ni catalyst,MgO promoter,and mSiO_(2)support.
基金This work was financially supported by the NSFZJ for Distinguished Young Scholars(LR16B010002)National Natural Science Foundation of China(21673160,51920105004,11574058,21671067,22172054,and 21972046)+1 种基金Guangzhou Key Laboratory of Low Dimensional Materials and Energy Storage Devices(201905010002)general program of the Natural Science Foundation of Guangdong Province(2019A1515011563).
文摘Photonic crystal(PC)patterns have shown wide applications in optical devices,information encryption,anticounterfeiting,etc.Unfortunately,it is stll a great challenge to reconfigure the PC patterns once fabricated.Herein,a new strategy is presented to reconfigure self-recordable PC patterns by printing local patterns into the chameleon-inspired PC papers using the phase change material(PCM)as ink and then erasing the patterns in ethanol.Multicolor and high-resolution(25 and 75μm for dot and lines,respectively)patterns can be eficiently and repeatedly reconfigured.In addition,the photonic patterns based on the PC paper and PCM combinations are gifted with mechanochromic characteristics and can show programmable and reversible color change under pressure.The high melting point of the ink,nonclosely packed structures of the PC paper,and the similar solubility parameter of PC paper,PCM,and ethanol are the keys for all these characteristics.This work offers a simple,flexible,efficient way to reconfigure PC patterns with mechanochromic properties and could open up exciting applications for novel hand-operation-based anticounterfeiting and opticaldevices.
基金the US National Science Foundation(DMR-1810485)J.Ge acknowledges the support from the National Natural Science Foundation of China(21972046).
文摘Expensive instruments and complicated data processing are often required to discriminate solvents with similar structures and properties.Colorimetric sensors with high selectivity,low cost,and good portability are highly desirable to simplify such detection tasks.Herein,we report the fabrication of a photonic crystal sensor based on the self-assembled resorcinol formaldehyde(RF)hollow spheres to realize colorimetric sensing of polar solvents,including homologs and isomers based on the saturated diffusion time.The diffusion of solvent molecules through the photonic crystal film exhibits a unique three-step diffusion profile accompanied by a dynamic color change,as determined by the physicochemical properties of the solvent molecules and their interactions with the polymer shells,making it possible to accurately identify the solvent type based on the dynamic reflection spectra or visual perception.With its superior selectivity and sensitivity,this single-component colorimetric sensor represents a straightforward tool for convenient solvent detection and identification.
基金This work was supported by the National Natural Science Foundation of China(Nos.22172054 and 21972046).
文摘The catalytic performance of TiO_(2)in photoreduction of CO_(2)is limited by its weak absorption in the visible range.In this work,a photonic crystal supported blue TiO_(2)photocatalyst(BTPC)was prepared to demonstrate a 5-6 times higher activity and improved CH_(4)selectivity compared to the BT catalysts deposited on quartz plate.By investigating the influence of the reflection intensity and wavelength of PC support,the superior catalytic performance was found to be originated from the enhanced light absorption of BT and the increased surface electron density brought by the PC support.Based on the study of BT loading on support,multilayer BTPC catalyst was designed to take the most advantage of the transmitted light and achieve a higher conversion of CO_(2)in the unit area of irradiation.
