Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most efficient.Nevertheless,the sluggish diffusion ...Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most efficient.Nevertheless,the sluggish diffusion and doping kinetics of precursors with high melting points,along with imprecise regulation,have raised the debate on whether Cs doping could make sense.For this matter,we attempt to confirm the positive effects of Cs doping on multifunctional photocatalysis by first using cesium acetate with the character of easy manipulation.The optimized Csdoped g-C_(3)N_(4)(CCN)shows a 41.6-fold increase in visible-light-driven hydrogen evolution reaction(HER)compared to pure g-C_(3)N_(4) and impressive degradation capability,especially with 77%refractory tetracycline and almost 100%rhodamine B degradedwithin an hour.The penetration ofCs+is demonstrated to be a mode of interlayer doping,and Cs–N bonds(especially with sp^(2) pyridine N in C═N–C),along with robust chemical interaction and electron exchange,are fabricated.This atomic configuration triggers the broadened spectral response,the improved charge migration,and the activated photocatalytic capacity.Furthermore,we evaluate the CCN/cadmium sulfide hybrid as a Z-scheme configuration,promoting the visible HER yield to 9.02 mmol g^(−1) h^(−1),which is the highest ever reported among all CCN systems.This work adds to the rapidly expanding field of manipulation strategies and supports further development of mediating served for photocatalysis.展开更多
Tin halide perovskites recently have attracted extensive research attention due to their similar electronic and band structures but non-toxicity compared with their lead analogues. In this work, we prepare high-qualit...Tin halide perovskites recently have attracted extensive research attention due to their similar electronic and band structures but non-toxicity compared with their lead analogues. In this work, we prepare high-quality CsSnX_(3)(X=Br,I) microplates with lateral sizes of around 1–4 μm by chemical vapor deposition and investigate their low-temperature photoluminescence(PL) properties. A remarkable splitting of PL peaks of the CsSnBr_(3)microplate is observed at low temperatures. Besides the possible structural phase transition at below 70 K, the multi-peak fittings using Gauss functions and the power-dependent saturation phenomenon suggest that the PL could also be influenced by the conversion from the emission of bound excitons into free excitons. With the increase of temperature, the peak position shows a blueshift tendency for CsSnI_(3), which is governed by thermal expansion. However, the peak position of the CsSnBr3microplate exhibits a transition from redshift to blueshift at ~160 K. The full width at half maximum of CsSnX_(3)broadens with increasing temperature, and the fitting results imply that longitudinal optical phonons dominate the electron–phonon coupling and the coupling strength is much more robust in CsSnBr3than in CsSnI_(3). The PL intensity of CsSnX_(3)microplates is suppressed due to the enhanced non-radiative relaxation and exciton dissociation competing with radiative recombination. According to the Arrhenius law, the exciton binding energy of CsSnBr_(3)is ~38.4 meV, slightly smaller than that of CsSnI_(3).展开更多
A nickel hexacyanoferrate(NiHCF)film electrode was prepared with NiHCF,conductive carbon black,and polyvinylidene difluoride,which was coated on graphite plate substrate for selective extraction of Cs^(+)ions by using...A nickel hexacyanoferrate(NiHCF)film electrode was prepared with NiHCF,conductive carbon black,and polyvinylidene difluoride,which was coated on graphite plate substrate for selective extraction of Cs^(+)ions by using electrochemically switched ion exchange(ESIX)technology.A potential-responsive ionpump system for efficient extraction of Cs+ions was designed,and the effect of wet film thicknesses,charging modes,flow rates,and chamber widths on Cs+ions extraction performance was investigated.In the system,the adsorption capacity and removal percentage of Cs^(+)ions on the NiHCF film electrode reached as high as 147.69 mg·g^(-1)and 92.47%,respectively.Furthermore,the NiHCF film electrode showed high selectivity for Cs^(+)ions and stability.After seven cycles of adsorption/desorption,the desorption percentage could reach about 100%.The excellent Cs^(+)extraction performance should be attributed to the strong driving force produced by the potential-responsive ion-pumping effect in the ESIX process,as well as the low ion transfer resistance of the film electrode which is caused by the special crystal structure of NiHCF.In addition,the NiHCF film electrode was implemented to work together with the bismuth oxybromide(BiOBr)film electrode to accomplish the simultaneous extraction of Cs^(+)and Br^(-).And the adsorption capacity and removal percentage of Br^(-)ions on the BiOBr film electrode reached 69.53 mg·g^(-1)and 77.32%,correspondingly.It is expected that such a potential-responsive ion-pump system based on NiHCF and BiOBr film electrodes could be used for the selective extraction and concentration of Cs^(+)and Br^(-)ions from salt lake brine.展开更多
在Cesium中展示大体量集中的三维模型需要进行渲染性能优化。Cesium原生方法效果不稳定,同时会降低渲染效果。为了尽可能避免该问题,提出相机状态变化期间高性能渲染机制,在相机状态变化期间停止加载图元,且仅在此期间采用会降低渲染效...在Cesium中展示大体量集中的三维模型需要进行渲染性能优化。Cesium原生方法效果不稳定,同时会降低渲染效果。为了尽可能避免该问题,提出相机状态变化期间高性能渲染机制,在相机状态变化期间停止加载图元,且仅在此期间采用会降低渲染效果但可提升性能的参数设置与算法,保证模型加载期间的渲染效果。同时提出基于堆的三维瓦片绘制命令限制方法,通过该方法可直接限制绘制命令数量,降低GPU计算量。实验证明,相机状态变化期间高性能渲染机制可行。在该机制中提升最大屏幕空间误差(max screen space error,MSSE)以及限制绘制命令对提升渲染性能的效果均显著优于降低分辨率比例(resolution scale,RS)。而限制绘制命令对渲染性能提升的稳定性优于提升MSSE。展开更多
基金supported primarily by the National Natural Science Foundation of China(Contract No.21975245,51972300,62274155,and U20A20206)the National Key Research and Development Program of China(Grant No.2018YFE0204000)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB43000000)the National Natural Science Foundation of China under Grant No.62175231.Prof.Kong Liu appreciates the support from the Youth Innovation Promotion Association,the Chinese Academy of Sciences(No.2020114)the Beijing Nova Program(No.2020117).
文摘Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most efficient.Nevertheless,the sluggish diffusion and doping kinetics of precursors with high melting points,along with imprecise regulation,have raised the debate on whether Cs doping could make sense.For this matter,we attempt to confirm the positive effects of Cs doping on multifunctional photocatalysis by first using cesium acetate with the character of easy manipulation.The optimized Csdoped g-C_(3)N_(4)(CCN)shows a 41.6-fold increase in visible-light-driven hydrogen evolution reaction(HER)compared to pure g-C_(3)N_(4) and impressive degradation capability,especially with 77%refractory tetracycline and almost 100%rhodamine B degradedwithin an hour.The penetration ofCs+is demonstrated to be a mode of interlayer doping,and Cs–N bonds(especially with sp^(2) pyridine N in C═N–C),along with robust chemical interaction and electron exchange,are fabricated.This atomic configuration triggers the broadened spectral response,the improved charge migration,and the activated photocatalytic capacity.Furthermore,we evaluate the CCN/cadmium sulfide hybrid as a Z-scheme configuration,promoting the visible HER yield to 9.02 mmol g^(−1) h^(−1),which is the highest ever reported among all CCN systems.This work adds to the rapidly expanding field of manipulation strategies and supports further development of mediating served for photocatalysis.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 11974279, 12074311, 12004310, and 12261141662)。
文摘Tin halide perovskites recently have attracted extensive research attention due to their similar electronic and band structures but non-toxicity compared with their lead analogues. In this work, we prepare high-quality CsSnX_(3)(X=Br,I) microplates with lateral sizes of around 1–4 μm by chemical vapor deposition and investigate their low-temperature photoluminescence(PL) properties. A remarkable splitting of PL peaks of the CsSnBr_(3)microplate is observed at low temperatures. Besides the possible structural phase transition at below 70 K, the multi-peak fittings using Gauss functions and the power-dependent saturation phenomenon suggest that the PL could also be influenced by the conversion from the emission of bound excitons into free excitons. With the increase of temperature, the peak position shows a blueshift tendency for CsSnI_(3), which is governed by thermal expansion. However, the peak position of the CsSnBr3microplate exhibits a transition from redshift to blueshift at ~160 K. The full width at half maximum of CsSnX_(3)broadens with increasing temperature, and the fitting results imply that longitudinal optical phonons dominate the electron–phonon coupling and the coupling strength is much more robust in CsSnBr3than in CsSnI_(3). The PL intensity of CsSnX_(3)microplates is suppressed due to the enhanced non-radiative relaxation and exciton dissociation competing with radiative recombination. According to the Arrhenius law, the exciton binding energy of CsSnBr_(3)is ~38.4 meV, slightly smaller than that of CsSnI_(3).
基金supported by the National Natural Science Foundation of China(22108188,U21A20303,U20A20141)CAS Project for Young Scientists in Basic Research(YSBR-039)。
文摘A nickel hexacyanoferrate(NiHCF)film electrode was prepared with NiHCF,conductive carbon black,and polyvinylidene difluoride,which was coated on graphite plate substrate for selective extraction of Cs^(+)ions by using electrochemically switched ion exchange(ESIX)technology.A potential-responsive ionpump system for efficient extraction of Cs+ions was designed,and the effect of wet film thicknesses,charging modes,flow rates,and chamber widths on Cs+ions extraction performance was investigated.In the system,the adsorption capacity and removal percentage of Cs^(+)ions on the NiHCF film electrode reached as high as 147.69 mg·g^(-1)and 92.47%,respectively.Furthermore,the NiHCF film electrode showed high selectivity for Cs^(+)ions and stability.After seven cycles of adsorption/desorption,the desorption percentage could reach about 100%.The excellent Cs^(+)extraction performance should be attributed to the strong driving force produced by the potential-responsive ion-pumping effect in the ESIX process,as well as the low ion transfer resistance of the film electrode which is caused by the special crystal structure of NiHCF.In addition,the NiHCF film electrode was implemented to work together with the bismuth oxybromide(BiOBr)film electrode to accomplish the simultaneous extraction of Cs^(+)and Br^(-).And the adsorption capacity and removal percentage of Br^(-)ions on the BiOBr film electrode reached 69.53 mg·g^(-1)and 77.32%,correspondingly.It is expected that such a potential-responsive ion-pump system based on NiHCF and BiOBr film electrodes could be used for the selective extraction and concentration of Cs^(+)and Br^(-)ions from salt lake brine.
文摘在Cesium中展示大体量集中的三维模型需要进行渲染性能优化。Cesium原生方法效果不稳定,同时会降低渲染效果。为了尽可能避免该问题,提出相机状态变化期间高性能渲染机制,在相机状态变化期间停止加载图元,且仅在此期间采用会降低渲染效果但可提升性能的参数设置与算法,保证模型加载期间的渲染效果。同时提出基于堆的三维瓦片绘制命令限制方法,通过该方法可直接限制绘制命令数量,降低GPU计算量。实验证明,相机状态变化期间高性能渲染机制可行。在该机制中提升最大屏幕空间误差(max screen space error,MSSE)以及限制绘制命令对提升渲染性能的效果均显著优于降低分辨率比例(resolution scale,RS)。而限制绘制命令对渲染性能提升的稳定性优于提升MSSE。
