Bismuth vanadate(BiVO4)is a promising photoanode material owing to the narrow bandgap,appropriate band position,and excellent resistance against photocorrosion,however,the performance of photoelectrochemical(PEC)water...Bismuth vanadate(BiVO4)is a promising photoanode material owing to the narrow bandgap,appropriate band position,and excellent resistance against photocorrosion,however,the performance of photoelectrochemical(PEC)water splitting is largely limited by the poor carrier separation and transport ability.To address these issues,for the first time,we fabricate BiVO4 film/CuO nanocone p-n junctions as photoanodes by combing a facile spin-coating process and water bath reaction.This structure strengthens the light harvesting and promotes the charge separation and transport ability.The surface defects states are passivated by coating conformally ultrathin TiO2 onto CuO surface through atomic layer deposition(ALD)technique.Benefiting from the favorable morphology,energy band,and surface treatment,the BiVO4/CuO/TiO2 heterojunction generates an improved photocurrent that is much higher than pure BiVO4.The detailed mechanism investigations indicate that the synergetic optimization of charge separation and injection efficiency in the bulk and surface of photoelectrodes can significantly improve the performance of PEC cells.展开更多
Landsat-9 is the latest satellite of the Landsat program and provides useful agricultural remote sensing data.The earlier the crop distribution data is obtained,the greater the value of the data.However,whether Landsa...Landsat-9 is the latest satellite of the Landsat program and provides useful agricultural remote sensing data.The earlier the crop distribution data is obtained,the greater the value of the data.However,whether Landsat-9 image is suitable for the early-season mapping of winter garlic and winter wheat is a problem worthy of attention.Therefore,this study evaluates the potential to use two Landsat-9 images,acquired on 13 December 2021 and 30 January 2022,for the early-season identification of winter garlic and winter wheat in China.According to J-M(Jeffries-Matusita)distances,we evaluated the separability of winter garlic,winter wheat,and other ground objects based on the two Landsat-9 images.Then,winter garlic and winter wheat were extracted by using unsupervised classification method,i.e.the IsoData and K-means clustering algorithms,and supervised classification method,i.e.the Random Forest(RF),and Support Vector Machine(SVM)algorithms.The separability between garlic and wheat in January is stronger than that in December.The classification overall accuracy based on the Landsat-9 image on 30 January 2022 is 92.03% with a kappa coefficient of 0.87 using the SVM algorithm.This period is about 4 months earlier than the crop harvest period.Landsat-9 images have good potentiality for early-season mapping of winter garlic and winter wheat.展开更多
Photoelectrodes with a specific structure and composition have been proposed for improving the efficiency of solar water splitting. Here, a novel multijunction structure was fabricated, with Si nanowires as cores, ZnI...Photoelectrodes with a specific structure and composition have been proposed for improving the efficiency of solar water splitting. Here, a novel multijunction structure was fabricated, with Si nanowires as cores, ZnIn2S4 nanosheets as branches, and TiO2 films as sandwiched layers. This junction exhibited a superior photoelectrochemical performance with a maximum photoconversion efficiency of 0.51%, which is 795 and 64 times higher than that of a bare Si wafer and nanowires, respectively. The large enhancement was attributed to the effective electron-hole separation and fast excited carrier transport within the multijunctions resulting from their favorable energy band alignments with water redox potentials, and to the enlarged contact area for facilitating the electron transfer at the multijunction/electrolyte interface.展开更多
基金supported by the National Natural Science Foundation of China (51772197, 51422206, 51372159)1000 Youth Talents Plan+3 种基金Key University Science Research Project of Jiangsu Province (17KJA430013)333 High-level Talents Cultivation Project of Jiangsu ProvinceSix Talents Peak Project of Jiangsu ProvinceFunded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Bismuth vanadate(BiVO4)is a promising photoanode material owing to the narrow bandgap,appropriate band position,and excellent resistance against photocorrosion,however,the performance of photoelectrochemical(PEC)water splitting is largely limited by the poor carrier separation and transport ability.To address these issues,for the first time,we fabricate BiVO4 film/CuO nanocone p-n junctions as photoanodes by combing a facile spin-coating process and water bath reaction.This structure strengthens the light harvesting and promotes the charge separation and transport ability.The surface defects states are passivated by coating conformally ultrathin TiO2 onto CuO surface through atomic layer deposition(ALD)technique.Benefiting from the favorable morphology,energy band,and surface treatment,the BiVO4/CuO/TiO2 heterojunction generates an improved photocurrent that is much higher than pure BiVO4.The detailed mechanism investigations indicate that the synergetic optimization of charge separation and injection efficiency in the bulk and surface of photoelectrodes can significantly improve the performance of PEC cells.
基金supported by the Henan Provincial Science and Technology Research and Development Plan Joint Fund,China[grant number 222103810029]Open Fund of Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions(Henan University),Ministry of Education[grant number GTYR202204]+4 种基金the National Natural Science Foundation of China[grant number 32130066]Open Fund of Henan Dabieshan National Field Observation and Research Station of Forest Ecosystem[grant number 2023XYQN01]Natural Science Foundation of China[grant number 42301104]Postdoctoral Fellowship Program of CPSF[grant number GZC20230677]the major project of the Collaborative Innovation Center on Yellow River Civilization,jointly built by the Henan province and the Ministry of Education[grant number 2020M19].
文摘Landsat-9 is the latest satellite of the Landsat program and provides useful agricultural remote sensing data.The earlier the crop distribution data is obtained,the greater the value of the data.However,whether Landsat-9 image is suitable for the early-season mapping of winter garlic and winter wheat is a problem worthy of attention.Therefore,this study evaluates the potential to use two Landsat-9 images,acquired on 13 December 2021 and 30 January 2022,for the early-season identification of winter garlic and winter wheat in China.According to J-M(Jeffries-Matusita)distances,we evaluated the separability of winter garlic,winter wheat,and other ground objects based on the two Landsat-9 images.Then,winter garlic and winter wheat were extracted by using unsupervised classification method,i.e.the IsoData and K-means clustering algorithms,and supervised classification method,i.e.the Random Forest(RF),and Support Vector Machine(SVM)algorithms.The separability between garlic and wheat in January is stronger than that in December.The classification overall accuracy based on the Landsat-9 image on 30 January 2022 is 92.03% with a kappa coefficient of 0.87 using the SVM algorithm.This period is about 4 months earlier than the crop harvest period.Landsat-9 images have good potentiality for early-season mapping of winter garlic and winter wheat.
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Nos. 51422206 and 51372159）, 1000 Talents Plan for Young Researchers, ＂Shuangchuang＂ Program of Jiangsu Province, a Project Supported by Jiangsu Science and Technology Committee for Distinguished Young Scholars （No. BK20140009）, the National Basic Research Program of China （973 Program） （No. 2015CB358600） and a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions （PAPD）. We also acknowledge Jiangsu Nata Opto- electronic Materials Co. Ltd. for providing high purity TDMAT precursor for deposition of TiO2 thin films.
文摘Photoelectrodes with a specific structure and composition have been proposed for improving the efficiency of solar water splitting. Here, a novel multijunction structure was fabricated, with Si nanowires as cores, ZnIn2S4 nanosheets as branches, and TiO2 films as sandwiched layers. This junction exhibited a superior photoelectrochemical performance with a maximum photoconversion efficiency of 0.51%, which is 795 and 64 times higher than that of a bare Si wafer and nanowires, respectively. The large enhancement was attributed to the effective electron-hole separation and fast excited carrier transport within the multijunctions resulting from their favorable energy band alignments with water redox potentials, and to the enlarged contact area for facilitating the electron transfer at the multijunction/electrolyte interface.
