Ceria nanoparticles(CeO_(2) NPs)have become popular materials in biomedical and industrial fields due to their potential applications in anti-oxidation,cancer therapy,photocatalytic degradation of pollutants,sensors,e...Ceria nanoparticles(CeO_(2) NPs)have become popular materials in biomedical and industrial fields due to their potential applications in anti-oxidation,cancer therapy,photocatalytic degradation of pollutants,sensors,etc.Many methods,including gas phase,solid phase,liquid phase,and the newly proposed green synthesis method,have been reported for the synthesis of CeO_(2) NPs.Due to the wide application of CeO_(2) NPs,concerns about their adverse impacts on human health have been raised.This review covers recent studies on the biomedical applications of CeO_(2) NPs,including their use in the treatment of various diseases(e.g.,Alzheimer's disease,ischemic stroke,retinal damage,chronic inflammation,and cancer).CeO_(2) NP toxicity is discussed in terms of the different systems of the human body(e.g.,cytotoxicity,genotoxicity,respiratory toxicity,neurotoxicity,and hepatotoxicity).This comprehensive review covers both fundamental discoveries and exploratory progress in CeO_(2) NP research that may lead to practical developments in the future.展开更多
Solar-driven overall conversion of CO_(2)and H_(2)O into fuels and chemicals shows an ultimate strategy for carbon neutrality yet remains a huge challenge.Herein,an integrated photocatalytic redox architecture of Zn N...Solar-driven overall conversion of CO_(2)and H_(2)O into fuels and chemicals shows an ultimate strategy for carbon neutrality yet remains a huge challenge.Herein,an integrated photocatalytic redox architecture of Zn NPs/GaN Nanowires(NWs)/Si is explored for light-driven overall conversion of CO_(2)and H_(2)O into CH_(4)and H_(2)O_(2)simultaneously without any external sacrificial agents and additives.The as-designed architecture affords a benchmark CH_(4)activity of 189 mmol gcat^(-1)h^(-1)with a high selectivity of 93.6%,in the synchronized formation of H_(2)O_(2)at a considerable rate of 25 m g^(-1)h^(-1).Moreover,a considerable turnover number of 27,280 mol CH_(4)per mol Zn was achieved over a long-term operation of 80 h.By operando spectroscopic characterizations,isotope experiments,and density functional theory calculations,it is unraveled that Zn sites are synergetic with GaN to drive CO_(2)-to-CH_(4)conversion with a lowered energy barrier of 0.27 eV while inhibiting hydrogen evolution reaction with a relatively high energy barrier of 0.93 eV.Notably,owing to the unique surface properties of GaN,water is split into*OH and*H,followed by the formation of H_(2)O_(2)because of the alleviated adsorption strength of*OH by Zn NPs.Together,the hierarchical architecture enables the achievement of high activity and high selectivity of CH_(4)from CO_(2)reduction in distilled water along with the generation of H_(2)O_(2).This work provides an integrated photocatalytic redox architecture for the synchronized production of CH_(4)and H_(2)O_(2)with the only inputs of CO_(2),distilled water,and light.展开更多
Investigating closely stacked GaN/AlN multiple quantum wells(MQWs)by means of cathodoluminescence spectroscopy directly performed in a scanning transmission electron microscope,we have reached an ultimate spatial reso...Investigating closely stacked GaN/AlN multiple quantum wells(MQWs)by means of cathodoluminescence spectroscopy directly performed in a scanning transmission electron microscope,we have reached an ultimate spatial resolution ofσCL=1.8 nm.The pseudomorphically grown MQWs with high interface quality emit in the deep ultraviolet spectral range.Demonstrating the capability of resolving the 10.8 nm separated,ultra-thin quantum wells,a cathodoluminescence profile was taken across individual ones.Applying a diffusion model of excitons generated by a Gaussian-broadened electron probe,the spatial resolution of cathodoluminescence down to the free exciton Bohr radius scale has been determined.展开更多
Near-infrared stimulated emission from a high-quality InN layer under optical pumping was observed with a threshold excitation power density of 0.3 and 4 kW cm^(−2) at T=8 and 77 K,respectively.To achieve such a low t...Near-infrared stimulated emission from a high-quality InN layer under optical pumping was observed with a threshold excitation power density of 0.3 and 4 kW cm^(−2) at T=8 and 77 K,respectively.To achieve such a low threshold power density,vicinal GaN substrates were used to reduce the edge-component threading dislocation(ETD)density of the InN film.Cross-sectional transmission electron microscopy images reveal that the annihilation of ETDs can be divided into two steps,and the ETD density can be reduced to approximately 5×10^(8) cm^(−2) near the surface of the 5-μm-thick film.The well-resolved phonon replica of the band-to-band emission in the photoluminescence spectra at 9 K confirm the high quality of the InN film.As a result,the feasibility of InN-based photonic structures and the underlying physics of their growth and emission properties are demonstrated.展开更多
基金supported by the National Natural Science Foundation of China(Nos.32161143035 and 81970826)the Yantai Science and Technology Innovation Development Plan(No.2022XDRH033),China。
文摘Ceria nanoparticles(CeO_(2) NPs)have become popular materials in biomedical and industrial fields due to their potential applications in anti-oxidation,cancer therapy,photocatalytic degradation of pollutants,sensors,etc.Many methods,including gas phase,solid phase,liquid phase,and the newly proposed green synthesis method,have been reported for the synthesis of CeO_(2) NPs.Due to the wide application of CeO_(2) NPs,concerns about their adverse impacts on human health have been raised.This review covers recent studies on the biomedical applications of CeO_(2) NPs,including their use in the treatment of various diseases(e.g.,Alzheimer's disease,ischemic stroke,retinal damage,chronic inflammation,and cancer).CeO_(2) NP toxicity is discussed in terms of the different systems of the human body(e.g.,cytotoxicity,genotoxicity,respiratory toxicity,neurotoxicity,and hepatotoxicity).This comprehensive review covers both fundamental discoveries and exploratory progress in CeO_(2) NP research that may lead to practical developments in the future.
基金supported by the National Key Research and Development Program of China(2023YFB4004900)Shanghai Pilot Program for Basic Research-Shanghai Jiao Tong University(21TQ1400211)+5 种基金the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(SL2022MS007)the National Natural Science Foundation of China(22109095)the National Natural Science Foundation of China(62305005,62321004,and 62227817)Beijing Natural Science Foundation(z200004)the Natural Sciences and Engineering Research Council of Canada Discovery Grant(RGPIN-2017-05187)McGill Engineering Doctoral Award(MEDA),and Digital Alliance of Canada-computational resources.
文摘Solar-driven overall conversion of CO_(2)and H_(2)O into fuels and chemicals shows an ultimate strategy for carbon neutrality yet remains a huge challenge.Herein,an integrated photocatalytic redox architecture of Zn NPs/GaN Nanowires(NWs)/Si is explored for light-driven overall conversion of CO_(2)and H_(2)O into CH_(4)and H_(2)O_(2)simultaneously without any external sacrificial agents and additives.The as-designed architecture affords a benchmark CH_(4)activity of 189 mmol gcat^(-1)h^(-1)with a high selectivity of 93.6%,in the synchronized formation of H_(2)O_(2)at a considerable rate of 25 m g^(-1)h^(-1).Moreover,a considerable turnover number of 27,280 mol CH_(4)per mol Zn was achieved over a long-term operation of 80 h.By operando spectroscopic characterizations,isotope experiments,and density functional theory calculations,it is unraveled that Zn sites are synergetic with GaN to drive CO_(2)-to-CH_(4)conversion with a lowered energy barrier of 0.27 eV while inhibiting hydrogen evolution reaction with a relatively high energy barrier of 0.93 eV.Notably,owing to the unique surface properties of GaN,water is split into*OH and*H,followed by the formation of H_(2)O_(2)because of the alleviated adsorption strength of*OH by Zn NPs.Together,the hierarchical architecture enables the achievement of high activity and high selectivity of CH_(4)from CO_(2)reduction in distilled water along with the generation of H_(2)O_(2).This work provides an integrated photocatalytic redox architecture for the synchronized production of CH_(4)and H_(2)O_(2)with the only inputs of CO_(2),distilled water,and light.
基金National Key Research and Development Program of China(2017YFE0100300)Science Challenge Project(TZ2016003)+1 种基金National Natural Science Foundation of China(61734001,61521004,61774004)Deutsche Forschungsgemeinschaft(Research Instrumentation Program INST272/148-1,Collaborative Research Center SFB 787)。
文摘Investigating closely stacked GaN/AlN multiple quantum wells(MQWs)by means of cathodoluminescence spectroscopy directly performed in a scanning transmission electron microscope,we have reached an ultimate spatial resolution ofσCL=1.8 nm.The pseudomorphically grown MQWs with high interface quality emit in the deep ultraviolet spectral range.Demonstrating the capability of resolving the 10.8 nm separated,ultra-thin quantum wells,a cathodoluminescence profile was taken across individual ones.Applying a diffusion model of excitons generated by a Gaussian-broadened electron probe,the spatial resolution of cathodoluminescence down to the free exciton Bohr radius scale has been determined.
基金partially supported by the National Natural Sci-ence Foundation of China(Grants No.61734001,61774004 and 61904002)the Beijing Outstanding Young Scientist Program(Grant No.BJJWZYJH0120191000103)the Science Challenge Project(Grant No.TZ2018003).
文摘Near-infrared stimulated emission from a high-quality InN layer under optical pumping was observed with a threshold excitation power density of 0.3 and 4 kW cm^(−2) at T=8 and 77 K,respectively.To achieve such a low threshold power density,vicinal GaN substrates were used to reduce the edge-component threading dislocation(ETD)density of the InN film.Cross-sectional transmission electron microscopy images reveal that the annihilation of ETDs can be divided into two steps,and the ETD density can be reduced to approximately 5×10^(8) cm^(−2) near the surface of the 5-μm-thick film.The well-resolved phonon replica of the band-to-band emission in the photoluminescence spectra at 9 K confirm the high quality of the InN film.As a result,the feasibility of InN-based photonic structures and the underlying physics of their growth and emission properties are demonstrated.
