Selectively harnessing photo-induced carriers to control surface photo-redox reactions can enable currently limited specificity in photocatalytic applications. By using a new approach to switching between dominant electron and hole charge transfer on the surfaces of metal oxide nanocrystals, depending on the optimal carrier for specific application functionality in photocatalytic pollutant degradation, H production, CO reduction, and gas sensing. The approach is based on the surface redox properties of custom-designed p-n hetero-structured hybrid nanoparticles (NPs) containing copper oxide, and wide-gap metal oxide semiconductors (MOSs).
View Article and Find Full Text PDFHeterostructural engineering and noble metal coupling are effective strategies to optimize semiconductor photocatalytic materials. In this work, (Ag, Mn2O3)-codecorated ZnO nanoparticles with different Mn2O3 contents (0-10 mol%) were synthesized by integrating the two strategies by a facile two-step polymer network-gel process. The photocatalytic activity of Ag/ZnO (AZM0) was significantly enhanced with the optimum Mn2O3 molar ratio of 3 mol%.
View Article and Find Full Text PDFDecorating metal oxides with wide band-gap semiconductor nano-particles constitute an important approach for synthesizing nano-photocatalysts, where the photocatalytic activity is attributed to the band diagram related effective charge separation and external in-band quantum yield (EIQY). However, up to now, the correlation between the irradiation intensity and the functionalization of the in-band quantum yield has not yet been explained. In this work, by investigating the photocatalytic activity of ZnO and CuO/ZnO (CZO) nano-photocatalysts under various irradiative intensities, we show that the effective charge separation in the CuO/ZnO band alignment is sensitive to weak illumination, while ZnO exhibits a competitive photocatalytic activity with CZO under strong illumination.
View Article and Find Full Text PDFA series of ZnO-based complex architectures including Mn-doped ZnO, Ag/ZnO and Ag-decorated Mn:ZnO nanocomposites were fabricated by a facile polymer network gel method. The photocatalytic performance of the as-synthesized products was evaluated by the degradation of methylene blue (MB), methyl orange (MO) and rhodamine B (RhB) under simulated sunlight irradiation. The Mn:ZnO/Ag photocatalyst achieves the superior photodegradation efficiency, which is three times higher than that of pure ZnO and two times that of the Ag/ZnO composite.
View Article and Find Full Text PDFThe construction of heterostructured photocatalyst with an appropriate energy band structure will help realize highly efficient photo-excited charge separation. In this study, ternary CuO/CeO/ZnO nano-particle (NP) composites were synthesized by a facile two-step sol-gel method, which exhibit significantly enhanced photocatalytic degradation performance for various organic pollutants under UV and visible light excitation. The photo-responses to both UV and visible light, as well as the visible light absorption and utilization rates of ZnO are found to be synergistically intensified by CeO and CuO co-coupling.
View Article and Find Full Text PDFImportance: Patients with nonvalvular atrial fibrillation at risk of stroke should receive oral anticoagulants (OAC). However, approximately 1 in 8 patients in the Global Anticoagulant Registry in the Field (GARFIELD-AF) registry are treated with antiplatelet (AP) drugs in addition to OAC, with or without documented vascular disease or other indications for AP therapy.
Objective: To investigate baseline characteristics and outcomes of patients who were prescribed OAC plus AP therapy vs OAC alone.
Introduction: In critical care observational studies, when clinicians administer different treatments to sicker patients, any treatment comparisons will be confounded by differences in severity of illness between patients. We sought to investigate the extent that observational studies assessing treatments are at risk of incorrectly concluding such treatments are ineffective or even harmful due to inadequate risk adjustment.
Methods: We performed Monte Carlo simulations of observational studies evaluating the effect of a hypothetical treatment on mortality in critically ill patients.