Low-coordination environment design of single Co atoms for efficient CO_(2) photoreduction

Photocatalytic carbon dioxide(CO_(2))to carbon monoxide(CO)offers a promising way for both alleviating the greenhouse effect and meeting the industrial demand.Herein,we constructed a Co single-atom catalyst with intentional low-coordination environment design on porous ZnO(denoted as Co1/ZnO).Impressively,Co1/ZnO exhibited a remarkable activity with a CO yield rate of 22.25 mmol·g^(-1)·h^(-1) and a selectivity of 80.2%for CO_(2) photoreduction reactions under visible light.The incorporation of single Co atoms provided an additional photo-generated electron transfer channel,which suppressed the carrier recombination of photocatalysts.Moreover,the unsaturated Co active sites were capable to adsorb CO_(2) molecule spontaneously,thus facilitating the activation of CO_(2) molecule during CO_(2) reduction course.

Association of emergency room visits for respiratory diseases with sources of ambient PM2.5

Previous studies have reported associations of short-term exposure to different sources of ambient fine particulate matter(PM2.5)and increased mortality or hospitalizations for respiratory diseases.Few studies,however,have focused on the short-term effects of source-specific PM2.5 on emergency room visits(ERVs)of respiratory diseases.Source apportionment for PM2.5 was performed with Positive Matrix Factorization(PMF)and generalized additive model was applied to estimate associations between source-specific PM2.5 and respiratory disease ERVs.The association of PM2.5 and total respiratory ERVs was found on lag4(RR=1.011,95%CI:1.002,1.020)per interquartile range(76μg/m3)increase.We found PM2.5 to be significantly associated with asthma,bronchitis and chronic obstructive pulmonary disease(COPD)ERVs,with the strongest effects on lag5(RR=1.072,95%CI:1.024,1.119),lag4(RR=1.104,95%CI:1.032,1.176)and lag3(RR=1.091,95%CI:1.047,1.135),respectively.The estimated effects of PM2.5 changed little after adjusting for different air pollutants.Six primary PM2.5 sources were identified using PMF analysis,including dust/soil(6.7%),industry emission(4.5%),secondary aerosols(30.3%),metal processing(3.2%),coal combustion(37.5%)and traffic-related source(17.8%).Some of the sources were identified to have effects on ERVs of total respiratory diseases(dust/soil,secondary aerosols,metal processing,coal combustion and traffic-related source),bronchitis ERVs(dust/soil)and COPD ERVs(traffic-related source,industry emission and secondary aerosols).Different sources of PM2.5 contribute to increased risk of respiratory ERVs to different extents,which may provide potential implications for the decision making of air quality related policies,rational emission control and public health welfare.