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1.
ACS Appl Mater Interfaces ; 16(3): 3368-3387, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38214573

RESUMO

The electrochemical synthesis of syngas (CO and H2) has garnered considerable attention in the context of Fischer-Tropsch (FT) synthesis employing thermal catalysts. Nonetheless, the need for a novel, cost-effective technique persists. In this investigation, we introduce a direct electrochemical (dEC) approach for FT synthesis that functions under ambient conditions by utilizing a p-block element (Sn and In) overlaid Cu electrode. Surface *CO and H* species were obtained in an electrolytic medium through the CO2 + H+ + e- → HOOCad → *CO (or direct CO adsorption) and H+ + e- → H* reactions, respectively. We have observed C2-7 long-chain hydrocarbons with a CnH2n+2/CnH2n ratio of 1-3, and this observation can be explained through the process of C-C coupling chain growth of the conventional FT synthesis, based on the linearity of the Anderson-Schulz-Flory equation plots. Thick Sn and In overlayers resulted in the dominant production of formate, while CO and C2H4 production were found to be proportional and inversely correlated to H2, C2H6, and C3-7 hydrocarbon production. The EC CO2/CO reduction used in dEC FT synthesis offers valuable insights into the mechanism of C2+ production and holds promise as an eco-friendly approach to producing long-chain hydrocarbons for energy and environmental purposes.

2.
Front Chem ; 10: 814766, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35223770

RESUMO

Recycled valuable energy production by the electrochemical CO2 reduction method has explosively researched using countless amounts of developed electrocatalysts. Herein, we have developed hybrid sandwiched Ga2O3:ZnO/indium/ZnO nanorods (GZO/In/ZnONR) and tested their photoelectrocatalytic CO2 reduction performances. Gas chromatography and nuclear magnetic spectroscopy were employed to examine gas and liquid CO2 reduction products, respectively. Major products were observed to be CO, H2, and formate whose Faradaic efficiencies were highly dependent on the relative amounts of overlayer GZO and In spacer, as well as applied potential and light irradiation. Overall, the present study provides a new strategy of controlling CO2 reduction products by developing a sandwiched hybrid catalyst system for energy and environment.

3.
Nanomaterials (Basel) ; 11(8)2021 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-34443738

RESUMO

ZIF-derivatized catalysts have shown high potential in catalysis. Herein, bean sprout-like Co-TiO2/Ti nanostructures were first synthesized by thermal treatment at 800 °C under Ar-flow conditions using sacrificial ZIF-67 templated on Ti sheets. It was observed that ZIF-67 on Ti sheets started to thermally decompose at around 350 °C and was converted to the cubic phase Co3O4. The head of the bean sprout structure was observed to be Co3O4, while the stem showed a crystal structure of rutile TiO2 grown from the metallic Ti support. Cu sputter-deposited Co-TiO2/Ti nanostructures were also prepared for photocatalytic and electrocatalytic CO2 reduction performances, as well as electrochemical oxygen reaction (OER). Gas chromatography results after photocatalytic CO2 reduction showed that CH3OH, CO and CH4 were produced as major products with the highest MeOH selectivity of 64% and minor C2 compounds of C2H2, C2H4 and C2H6. For electrocatalytic CO2 reduction, CO, CH4 and C2H4 were meaningfully detected, but H2 was dominantly produced. The amounts were observed to be dependent on the Cu deposition amount. Electrochemical OER performances in 0.1 M KOH electrolyte exhibited onset overpotentials of 330-430 mV (vs. RHE) and Tafel slopes of 117-134 mV/dec that were dependent on Cu-loading thickness. The present unique results provide useful information for synthesis of bean sprout-like Co-TiO2/Ti hybrid nanostructures and their applications to CO2 reduction and electrochemical water splitting in energy and environmental fields.

4.
Nanomaterials (Basel) ; 11(5)2021 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-34068042

RESUMO

Aluminum oxide (Al2O3) has abundantly been used as a catalyst, and its catalytic activity has been tailored by loading transition metals. Herein, γ-Al2O3 nanosheets were prepared by the solvothermal method, and transition metals (M = Co, Ni, Cu, Rh, Pd, Ag, Ir, Pt, and Au) were loaded onto the nanosheets. Big data sets of thermal CO oxidation and photocatalytic CO2 reduction activities were fully examined for the transition metal-loaded Al2O3 nanosheets. Their physicochemical properties were examined by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction crystallography, and X-ray photoelectron spectroscopy. It was found that Rh, Pd, Ir, and Pt-loading showed a great enhancement in CO oxidation activity while other metals negated the activity of bare Al2O3 nanosheets. Rh-Al2O3 showed the lowest CO oxidation onset temperature of 172 °C, 201 °C lower than that of bare γ-Al2O3. CO2 reduction experiments were also performed to show that CO, CH3OH, and CH4 were common products. Ag-Al2O3 nanosheets showed the highest performances with yields of 237.3 ppm for CO, 36.3 ppm for CH3OH, and 30.9 ppm for CH4, 2.2×, 1.2×, and 1.6× enhancements, respectively, compared with those for bare Al2O3. Hydrogen production was found to be maximized to 20.7 ppm during CO2 reduction for Rh-loaded Al2O3. The present unique pre-screening test results provided very useful information for the selection of transition metals on Al2O3-based energy and environmental catalysts.

5.
ACS Appl Mater Interfaces ; 13(23): 27594-27611, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34080410

RESUMO

Understanding the electrochemical behaviors of Ce(III)/Ce(IV) ions is essential for better treatment, separation, and recycling of lanthanide (Ln) and actinide (An) elements. Herein, electrochemical redox behavior and interconversion of Ce(III)/Ce(IV) ions and their recoveries were demonstrated over newly developed thio-terpyridine-functionalized Au-modified carbon paper electrodes in acidic and neutral electrolytes. Cyclic voltammetry and amperometry were performed for the electrodes with and without thio-terpyridine functionalization. Ce oxide nanostructure recovery was successfully conducted by amperometry, and the electrodeposited nanostructured Ce materials were fully characterized by scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction crystallography, and X-ray photoelectron spectroscopy. Geometry optimization and the electronic energy state calculations were conducted by density functional theory at the B3LYP/GENECP level for the complexes of Ce(III) and Ce(IV) ions with the thio-terpyridine in an aqueous state. The present unique results provide valuable information on understanding redox behaviors of Ln and An ions for their recycling and treatment processes.

6.
Nanomaterials (Basel) ; 10(10)2020 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-32987906

RESUMO

Energy recycling and production using abundant atmospheric CO2 and H2O have increasingly attracted attention for solving energy and environmental problems. Herein, Pt-loaded Ti sheets were prepared by sputter-deposition and Pt4+-reduction methods, and their catalytic activities on both photocatalytic CO2 reduction and electrochemical hydrogen evolution were fully demonstrated. The surface chemical states were completely examined by X-ray photoelectron spectroscopy before and after CO2 reduction. Gas chromatography confirmed that CO, CH4, and CH3OH were commonly produced as CO2 reduction products with total yields up to 87.3, 26.9, and 88.0 µmol/mol, respectively for 700 °C-annealed Ti under UVC irradiation for 13 h. Pt-loading commonly negated the CO2 reduction yields, but CH4 selectivity was increased. Electrochemical hydrogen evolution reaction (HER) activity showed the highest activity for sputter-deposited Pt on 400 °C-annealed Ti with a HER current density of 10.5 mA/cm2 at -0.5 V (vs. Ag/AgCl). The activities of CO2 reduction and HER were found to be significantly dependent on both the nature of Ti support and the oxidation states (0,II,IV) of overlayer Pt. The present result could provide valuable information for designing efficient Pt/Ti-based CO2 recycle photocatalysts and electrochemical hydrogen production catalysts.

7.
Int J Qual Health Care ; 28(5): 580-585, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27650012

RESUMO

OBJECTIVES: This study aims to analyze the impact of Value Incentive Program (VIP) on the quality improvement of acute stroke care, and to determine the difference of effect by the size of hospitals. INTERVENTIONS: Adopting the VIP on the fifth acute stroke quality assessment. DESIGN/SETTING/PARTICIPANTS: Using paired t-test and student t-test, we compared the quality assessment results of the third assessment, which was publicly reported without the VIP implementation and the fifth assessment, on which the VIP was applied. The subjects of the third assessment were acute stroke admissions in 201 hospitals (44 tertiary and 157 general hospitals) from January to March 2010. The fifth assessment included 201 hospitals (42 tertiary and 159 general hospitals) from March to May 2013. MAIN OUTCOME MEASURES: Seven process indicators of acute stroke quality assessment and in-hospital mortality rate. RESULT: In comparison to the third assessment, five of the seven process indicators showed statistically significant improvement in the fifth assessment. Also, there were significant decreases in the interquartile ranges of five process indicators. This phenomenon was more notable in general hospitals. The in-hospital mortality rate of hemorrhagic stroke in general hospitals showed a statistically significant decrease from 20.8% in the third assessment to 11.6% (P < 0.05) in the fifth assessment. CONCLUSION: This study demonstrated that the VIP was effective in improving quality of acute stroke care. The improvement was more prominent in general hospitals, and led to reduced quality gaps among hospitals.


Assuntos
Motivação , Melhoria de Qualidade , Qualidade da Assistência à Saúde/normas , Acidente Vascular Cerebral , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , República da Coreia
8.
Int J Med Inform ; 84(11): 912-9, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26363001

RESUMO

OBJECTIVE: Outpatient clinics in Korea usually have local DUR (drug utilisation review) systems, which are integrated with EMRs or health insurance claims submission systems. Whenever, the government announces a list of drug contraindications, each local DUR system loads the list and applies it in practice. In December 2010, a nationwide DUR system was introduced. This study is to investigate the impact of the nationwide DUR system on prescribing practices where local DUR systems are already operating. METHODS: Between January 2009 and December 2012 the monthly number of drugs per prescription was retrieved from the health insurance claims data warehouse at the Health Insurance Review and Assessment (HIRA). The monthly proportions of 3 DDI (drug-drug interaction) pairs, 6 drug-age contraindications, and 3 drug-pregnancy contraindications from January 2007 to December 2012, at the outpatient clinic level, were also retrieved. An interrupted time series analysis was used for controlling government announcements of drug contraindications. RESULTS: There was no difference in the number of drugs per prescription before and after the introduction of the nationwide DUR system. Most proportions of the 3 DDI pairs, 6 drug-age contraindications, and 3 drug-pregnancy contraindications, were significantly reduced following the government announcement of drug contraindications in the short term and/or long term. CONCLUSION: The number of drugs per prescription was not related to the nationwide DUR introduction in places where local DUR systems are operating. The introduction of duplicate guidelines, in locations where the guidelines were already well followed, is considered to be the main reason for this. Furthermore, the Doctor's ignorance of alerts, and their continued substitution of regulated drugs, for non-regulated drugs, likely played a role in nullifying the effectiveness of the nationwide DUR system.


Assuntos
Interações Medicamentosas , Revisão de Uso de Medicamentos , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/prevenção & controle , Erros de Medicação/prevenção & controle , Instituições de Assistência Ambulatorial , Revisão de Uso de Medicamentos/normas , Revisão de Uso de Medicamentos/estatística & dados numéricos , Registros Eletrônicos de Saúde , Feminino , Humanos , Seguro Saúde , Masculino , Segurança do Paciente , Gravidez , Medicamentos sob Prescrição/uso terapêutico , República da Coreia
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