Hebei is one of the most air polluted provinces in China. According to the Ministry of Environmental Protection (MEP) for the severe fog-haze month of Jan. 2013, seven of the top ten most polluted cities in China are ...Hebei is one of the most air polluted provinces in China. According to the Ministry of Environmental Protection (MEP) for the severe fog-haze month of Jan. 2013, seven of the top ten most polluted cities in China are located in Hebei Province. In this study, the air pollution history and status of the Hebei Province are reviewed and discussed, using the governmental published Air Pollution Index (API), the academic observations by various scientific research groups and the long-term statistics of visibility and haze frequencies. It is found that within the Hebei Province, the air pollution in the southern cities is much more severe than the northern cities. Particulate matter (PM) is undoubtedly the major air pollutant, sulfur dioxide (SO2) and nitrogen oxides (NOX) pollutions are also unnegligible. Ozone (O3) pollution in larger cities, such as Shijiazhuang, is significant. Air pollution control history from 1998 is discussed as well. Although Hebei Province has made a great effort on air quality, the pollutant emissions, such as SO2 and fly ash, showed a notable increase in 2001 to 2006. However, after 2006 the emissions started to decrease due to the strict implementation of the national 11th Five Year Plan (FYP). In addition, regional jointly air pollution control and prevention strategies are expected in the future to substantially change the severe air pollution status in Hebei Province.展开更多
Nowadays,photoca-talytic water splitting for hydrogen production is widely recognized as a promising solution to solve both energy shortages and environmental pollution.Nevertheless,photocatalytic hydrogen evolution i...Nowadays,photoca-talytic water splitting for hydrogen production is widely recognized as a promising solution to solve both energy shortages and environmental pollution.Nevertheless,photocatalytic hydrogen evolution is currently hindered by challenges,such as inefficient photogenerated carrier separation and migration and inadequate light absorption by photocatalysts.To overcome such challenges,we herein engineered hollow Cu_(2-x)Se@ZnIn_(2)S_(4) core-shell heterostructures(HCSHs)via synergistic utilization of energy level engineering,interfacial engineering,and local surface plasmon resonance(LSPR)effect.The optimal sample exhibits an outstanding hydrogen evolution rate(46.78 mmol·g^(-1)·h^(-1))under visible-near-infrared(VIS-NIR)irradiation,which is 1.78 times that under VIS irradiation alone and 7.8 times that of ZnIn_(2)S_(4) reference under the same illumination condition.Comprehensive studies demonstrate that the built-in electric field within the p-n heterojunctions,along with the unique core-shell structure,significantly enhances the separation and directional migration of photogenerated carriers.Meanwhile,the NIR LSPR effect from the Cu_(2-x)Se component lowers the apparent activation energy and accelerates the reaction kinetics mainly via plasmonic hot electron-assisted cleavage of the adsorbed water,with photothermal heating providing a secondary contribution.This work is of great importance in developing highly efficient photocatalysts and in boosting LSPR-enhanced photocatalytic applications.展开更多
Beijing-Tianjin-Hebei area is the most air polluted region in China and the three neighborhood southern Hebei cities, Shijiazhuang, Xingtai, and Handan, are listed in the top ten polluted cities with severe PM2.5 poll...Beijing-Tianjin-Hebei area is the most air polluted region in China and the three neighborhood southern Hebei cities, Shijiazhuang, Xingtai, and Handan, are listed in the top ten polluted cities with severe PM2.5 pollution. The objective of this paper is to evaluate the impacts of aerosol direct effects on air aualitv over the southern Hebei cities, as well as the im0acts when considering those effects on source apportionment using three dimensional air quality models. The WRF/Chem model was applied over the East Asia and northern China at 36 and 12 km horizontal grid resolutions, respectively, for the period of January 2013, with two sets of simulations with or without aerosol-meteorology feedbacks. The source contributions of power plants, industrial, domestic, transportation, and agriculture are evaluated using the Brute-Force Method （BFM） under the two simulation configurations. Our results indicate that, although the increases in PM2.5 concentrations due to those effects over the three southern Hebei cities are only 3%-9% on monthly average they are much more significant under high PM2.5 Ioadmgs （-50 gg.m - when PM25 concentrations are higher than 400μg.m^-3）. When considering the aerosol feedbacks, the contributions of industrial and domestic sources assessed using the BFM will obviously increase （e.g., from 30% 34% to 32%-37% for industrial）, especiallY3under high PM2.5 loadings （e.g., from 36%-44% to 43%-47% for domestic when PM2.5〉400μg·m^-3）. Our results imply that the aerosol direct effects should not be ignored during severe pollution episodes, especially in short-term source apportionment using the BFM.展开更多
文摘Hebei is one of the most air polluted provinces in China. According to the Ministry of Environmental Protection (MEP) for the severe fog-haze month of Jan. 2013, seven of the top ten most polluted cities in China are located in Hebei Province. In this study, the air pollution history and status of the Hebei Province are reviewed and discussed, using the governmental published Air Pollution Index (API), the academic observations by various scientific research groups and the long-term statistics of visibility and haze frequencies. It is found that within the Hebei Province, the air pollution in the southern cities is much more severe than the northern cities. Particulate matter (PM) is undoubtedly the major air pollutant, sulfur dioxide (SO2) and nitrogen oxides (NOX) pollutions are also unnegligible. Ozone (O3) pollution in larger cities, such as Shijiazhuang, is significant. Air pollution control history from 1998 is discussed as well. Although Hebei Province has made a great effort on air quality, the pollutant emissions, such as SO2 and fly ash, showed a notable increase in 2001 to 2006. However, after 2006 the emissions started to decrease due to the strict implementation of the national 11th Five Year Plan (FYP). In addition, regional jointly air pollution control and prevention strategies are expected in the future to substantially change the severe air pollution status in Hebei Province.
基金financially supported by the National Natural Science Foundation of China(NSFC,Nos.22272008 and 21872011).
文摘Nowadays,photoca-talytic water splitting for hydrogen production is widely recognized as a promising solution to solve both energy shortages and environmental pollution.Nevertheless,photocatalytic hydrogen evolution is currently hindered by challenges,such as inefficient photogenerated carrier separation and migration and inadequate light absorption by photocatalysts.To overcome such challenges,we herein engineered hollow Cu_(2-x)Se@ZnIn_(2)S_(4) core-shell heterostructures(HCSHs)via synergistic utilization of energy level engineering,interfacial engineering,and local surface plasmon resonance(LSPR)effect.The optimal sample exhibits an outstanding hydrogen evolution rate(46.78 mmol·g^(-1)·h^(-1))under visible-near-infrared(VIS-NIR)irradiation,which is 1.78 times that under VIS irradiation alone and 7.8 times that of ZnIn_(2)S_(4) reference under the same illumination condition.Comprehensive studies demonstrate that the built-in electric field within the p-n heterojunctions,along with the unique core-shell structure,significantly enhances the separation and directional migration of photogenerated carriers.Meanwhile,the NIR LSPR effect from the Cu_(2-x)Se component lowers the apparent activation energy and accelerates the reaction kinetics mainly via plasmonic hot electron-assisted cleavage of the adsorbed water,with photothermal heating providing a secondary contribution.This work is of great importance in developing highly efficient photocatalysts and in boosting LSPR-enhanced photocatalytic applications.
文摘Beijing-Tianjin-Hebei area is the most air polluted region in China and the three neighborhood southern Hebei cities, Shijiazhuang, Xingtai, and Handan, are listed in the top ten polluted cities with severe PM2.5 pollution. The objective of this paper is to evaluate the impacts of aerosol direct effects on air aualitv over the southern Hebei cities, as well as the im0acts when considering those effects on source apportionment using three dimensional air quality models. The WRF/Chem model was applied over the East Asia and northern China at 36 and 12 km horizontal grid resolutions, respectively, for the period of January 2013, with two sets of simulations with or without aerosol-meteorology feedbacks. The source contributions of power plants, industrial, domestic, transportation, and agriculture are evaluated using the Brute-Force Method （BFM） under the two simulation configurations. Our results indicate that, although the increases in PM2.5 concentrations due to those effects over the three southern Hebei cities are only 3%-9% on monthly average they are much more significant under high PM2.5 Ioadmgs （-50 gg.m - when PM25 concentrations are higher than 400μg.m^-3）. When considering the aerosol feedbacks, the contributions of industrial and domestic sources assessed using the BFM will obviously increase （e.g., from 30% 34% to 32%-37% for industrial）, especiallY3under high PM2.5 loadings （e.g., from 36%-44% to 43%-47% for domestic when PM2.5〉400μg·m^-3）. Our results imply that the aerosol direct effects should not be ignored during severe pollution episodes, especially in short-term source apportionment using the BFM.
