Getting insights into gas-phase sulfation effect on catalytic performance of praseodymium oxides in NH_(3)-SCR of NO

Sulfation treatment has been widely used to promote the catalytic performance of ceria(CeO_(2))based catalysts for the selective catalytic reduction of NO by NH_(3)(NH_(3)-SCR of NO).Praseodymium oxide(PrO_(x)),another commonly used rare earth material with similar structural properties as CeO_(2),also shows satistactory redox properties due to the facile redox cycle of Pr^(3+)■Pr^(4+).In this work,gas phase sulfation treatment with varied duration was performed on PrO_(x) at 200℃,and the NH_(3)-SCR activity of sulfated PrO_(x) was evaluated.Based on the results of systematic characterizations(e.g.,N_(2)-physisorption,NH_(3) oxidation,NO oxidation,in situ diffuse Fourier transform infrared spectroscopy),it is revealed that the catalytic performance of sulfated PrO_(x)is highly dependent on the sulfation time(or the amount of sulfate species deposited on PrO_(x)),which has a significant impact on the competitive reaction between NH_(3) oxidation and NH_(3)-SCR of NO,thus determining the NH_(3)-SCR activity of PrO_(x).This work provides new insight into tuning the interaction between PrO_(x) surface and reactants(NO,NH_(3))via sulfation treatment,which cam guide the design and application of PrO_(x)based catalysts for NH_(3)-SCR of NO in the future.

Amphiphilic drug-drug conjugate for cancer therapy with combination of chemotherapeutic and antiangiogenesis drugs

The progression and metastasis of solid tumors strongly rely on the process of forming nascent blood vessels.However,using angiogenesis inhibitors alone does not meet the cancer treatment needs.Herein,we used the amphiphilic drug-drug conjugate(ADDC)strategy to fabricate a new drug conjugate with the combination of chemotherapeutic drug and antiangiogenesis drug together.With one-step esterification of hydrophilic floxuridine(FUDR)and hydrophobic pseudolaric acid B(PAB),the conjugate was synthesized.The amphiphilic property of FUDR-PAB conjugate induced the self-assembly to form nanoparticles in water.From further in vitro and in vivo experiments,this FUDR-PAB conjugate does not only have a high antitumor effect,but also shows efficient antianiogenesis property.These results offer a promising ADDC strategy for designing drugs with combination of chemotherapeutic drug and antiangiogenesis drug together.