Nitration-Promoted Vanadate Catalysts for Low-Temperature Selective Catalytic Reduction of NOX with NH3.

Vanadium-based catalysts have been commercially used in selective catalytic reduction (SCR), owing to their high catalytic activity and effectiveness across a wide temperature range; however, their catalytic efficiency decreases at lower temperatures under exposure to SOX. This decrease is largely due to ammonium sulfate generation on the catalyst surface. To overcome this limitation, we added ammonium nitrate to the V2O5-WO3/TiO2 catalyst, producing a V2O5-WO3/TiO2 catalyst with nitrate functional groups. With this approach, we found that it was possible to adjust the amount of these functional groups by varying the amount of ammonium nitrate. Overall, the resultant nitrate V2O5-WO3/TiO2 catalyst has large quantities of NO3- and chemisorbed oxygen, which improves the density of Brønsted and Lewis acid sites on the catalyst surface. Furthermore, the nitrated V2O5-WO3/TiO2 catalyst has a high NOX removal efficiency and N2 selectivity at low temperatures (i.e., 300 °C); this is because NO3- and chemisorbed oxygen, generated by nitrate treatment, facilitated the occurrence of a fast SCR reaction. The approach outlined in this study can be applied to a wide range of SCR catalysts, allowing for the development of more, low-temperature SCR catalysts.

Cl- and Al-Doped Argyrodite Solid Electrolyte Li6PS5Cl for All-Solid-State Lithium Batteries with Improved Ionic Conductivity.

Argyrodite solid electrolytes such as lithium phosphorus sulfur chloride (Li6PS5Cl) have recently attracted great attention due to their excellent lithium-ion transport properties, which are applicable to all-solid-state lithium batteries. In this study, we report the improved ionic conductivity of an argyrodite solid electrolyte, Li6PS5Cl, in all-solid-state lithium batteries via the co-doping of chlorine (Cl) and aluminum (Al) elements. Electrochemical analysis was conducted on the doped argyrodite structure of Li6PS5Cl, which revealed that the substitution of cations and anions greatly improved the ionic conductivity of solid electrolytes. The ionic conductivity of the Cl- and Al-doped Li6PS5Cl (Li5.4Al0.1PS4.7Cl1.3) electrolyte was 7.29 × 10-3 S cm-1 at room temperature, which is 4.7 times higher than that of Li6PS5Cl. The Arrhenius plot of the Li5.4Al0.1PS4.7Cl1.3 electrolyte further elucidated its low activation energy at 0.09 eV.

Polyol-Mediated Synthesis of V2O5-WO3/TiO2 Catalysts for Low-Temperature Selective Catalytic Reduction with Ammonia.

We demonstrated highly efficient selective catalytic reduction catalysts by adopting the polyol process, and the prepared catalysts exhibited a high nitrogen oxide (NOX) removal efficiency of 96% at 250 °C. The V2O5 and WO3 catalyst nanoparticles prepared using the polyol process were smaller (~10 nm) than those prepared using the impregnation method (~20 nm), and the small catalyst size enabled an increase in surface area and catalytic acid sites. The NOX removal efficiencies at temperatures between 200 and 250 °C were enhanced by approximately 30% compared to those of the catalysts prepared using the conventional impregnation method. The NH3-temperature-programmed desorption and H2-temperature-programmed reduction results confirmed that the polyol process produced more surface acid sites at low temperatures and enhanced the redox ability. The in situ Fourier-transform infrared spectra further elucidated the fast absorption of NH3 and its reduction with NO and O2 on the prepared catalyst surfaces. This study provides an effective approach to synthesizing efficient low-temperature SCR catalysts and may contribute to further studies related to other catalytic systems.

Outpatient (Same-day care) Neuroangiography and Neurointervention.

PURPOSE: There have been few reports regarding same-day discharge following uncomplicated procedures such as cerebral angiography and neurointervention. We present same-day experience with cerebral angiography and neurointervention during the past three years. MATERIALS AND METHODS: Four hundred and fifty-three patients underwent cerebral angiography or neurointervention at Asan Medical Center between January 2009 and December 2011. Of these patients, 249 (55%) underwent diagnostic catheter cerebral angiography and 204 patients (45%) underwent neurointerventional procedures as same-day procedures. We analyzed any complications, the modified patient-care process, the yearly trend in patient increases, disease categories, and the additional duration of admission for these procedures. RESULTS: The number of overall patients increased by an average of 51% annually. The disease categories included aneurysm (51%), atherosclerosis (11%) and arteriovenous malformation (10%), etc. for which the patient underwent angiography, and aneurysm (42%), venous malformation (28%), and arteriovenous malformation (17%), etc. for which patients underwent neurointervention. Same-day care patients were admitted to the intermediary care unit in the angiosuite. Neurointervention patients were sent to the neurology intensive unit after the procedure. The same-day care patients stayed in angiosuite for six hours following the transfemoral procedure. The mean admission duration for neurointervention was 2.4 days. There were no reported complications for the same-day care procedures. CONCLUSION: Our study revealed an increasing tendency toward same-day care for patients who require angiography and neurointervention. Further studies will be required to better define the cost-minimization effects of outpatient practice as well as the patient perception of this fast-tracking method. We propose that outpatient angiography and neurointervention will undoubtedly continue to increase over the next decade.