A low-temperature synthesis-induced defect formation strategy for stable hierarchical porous metal–organic frameworks

A stable hierarchical porous metal-organic framework PCN-56 with abundant Lewis acid sites(denoted as Defective-PCN-56) was synthesized by the low-temperature synthesis-induced defect formation method.The existence of mesopore in structure was confirmed by N2 sorption isotherm and the successful encapsulation of large dye molecules.The Defective-PCN-56 has higher loading capacity toward anti-cancer drug Doxo compared with that of "nearly ideal-crystal"(denoted as Ideal-PCN-56)synthesized at high temperature,showing potential application as drug carrier.The low-temperature synthesis-induced defect formation strategy presented here provides a new and facile way to synthesize stable MOFs with the combination of intrinsic micropore and additional mesopore as well as abundant Lewis acid sites.

Ozone and secondary organic aerosol formation potential from anthropogenic volatile organic compounds emissions in China

Volatile organic compounds （VOCs） are major precursors for ozone and secondary organic aerosol （SOA）, both of which greatly harm human health and significantly affect the Earth＇s climate. We simultaneously estimated ozone and SOA formation from anthropogenic VOCs emissions in China by employing photochemical ozone creation potential （POCP） values and SOA yields. We gave special attention to large molecular species and adopted the SOA yield curves from latest smog chamber experiments. The estimation shows that alkylbenzenes are greatest contributors to both ozone and SOA formation （36.0% and 51.6%, respectively）, while toluene and xylenes are largest contributing individual VOCs. Industry solvent use, industry process and domestic combustion are three sectors with the largest contributions to both ozone （24.7%, 23.0% and 17.8%, respectively） and SOA （22.9%, 34.6% and 19.6%, respectively） formation. In terms of the formation potential per unit VOCs emission, ozone is sensitive to open biomass burning, transportation, and domestic solvent use, and SOA is sensitive to industry process, domestic solvent use, and domestic combustion. Biomass stoves, paint application in industrial protection and buildings, adhesives application are key individual sources to ozone and SOA formation, whether measured by total contribution or contribution per unit VOCs emission. The results imply that current VOCs control policies should be extended to cover most important industrial sources, and the control measures for biomass stoves should be tightened. Finally, discrepant VOCs control policies should be implemented in different regions based on their ozone/aerosol concentration levels and dominant emission sources for ozone and SOA formation potential.