CO2 Methanation over Rh/CeO2 Studied with Infrared Modulation Excitation Spectroscopy and Phase Sensitive Detection

Methane is a well-established fuel molecule whose production from CO2 through methanation garners increasing interest as an energy storage solution. While often produced with Ni based catalysts, other metals are of interest thanks to higher robustness and activity-selectivity numbers. The Rh/CeO2 catalyst has shown appreciable properties for CO2 methanation and its structural dynamics has been studied in situ. However, the reaction pathway is unknown. Here, we present infrared modulation excitation spectroscopy measurements with phase sensitive detection of a Rh/CeO2 catalyst adsorbate composition during H2 pulsing (0–2 vol.%) to a constant CO2 (0.5 vol.%) feed. Various carbonyl (CO) and carbonate (b-CO3 /p-CO3 ) ad-species clearly respond to the hydrogen stimulus, making them potential reaction intermediates. The different CO ad-species are likely intermediates for product CO and CH4 but their individual contributions to the respective formations are not unambiguously ascertained. As for the carbonate dynamics, it might be linked to the reduction/oxidation of the CeO2 surface upon H2 pulsing. Formate (HCOO) ad-species are clearly visible but appear to be, if not spectators, linked to slow side reactions possibly also affected by CeO2 redox processes

Temporal aspects of teaching and learning - implications for pupils with physical disabilities

The aim of this study was to describe and try to understand how temporal structures in school setting influence the performance of daily school tasks for pupils with physical disabilities. Seven pupils between 7 and 15 years of age were included. Data were collected through field observations and semi-structured interviews with pupils and each pupil’s teacher. The findings show that pupils with disabilities often did not have the time to perform regular daily school activities such as reading and writing. The pupils’ time problems were to a large extent influenced by the teaching styles. Four teaching styles were identified. The number of pupils in the class seemed to influence the teacher’s choice of teaching style. Variation in teaching styles also could be understood in relation to how teachers handled an educational dilemma that was discovered. Implications of the study on teaching and learning in relation to pupils with physical disabilities are discussed

Why nitrogen oxide inhibits CO oxidation over highly dispersed platinum ceria catalysts

The influence of nitrogen oxide on the lean CO oxidation activity of highly dispersed Pt/ceria and reference Pt/alumina catalysts has been studied by kinetic measurements and infrared spectroscopic characterization. Co-feeding of nitrogen oxide leads to the formation of nitrates on the supports that induce a highly oxidized character of the Pt sites and in the case of Pt/ceria, inhibit ceria lattice oxygens to react with CO adsorbed on Pt rim sites via a Mars-van Krevelen mechanism below the ignition temperature. The build-up of nitrates below the light-off temperatures is faster when CO is present in the feed. Above the light-off temperatures, carbonates replace the nitrates while the catalytic activity remains high

Hampered PdO Redox Dynamics by Water Suppresses Lean Methane Oxidation over Realistic Palladium Catalysts

By use of operando spectroscopies under cycling reaction conditions, water is shown to hamper the redox dynamics of realistic palladium oxide nanoparticles dispersed onto alumina and hydrophobic zeolite supports thereby lowering the activity for total oxidation of methane. Water adsorption forms hydroxyl ad-species that block the methane and oxygen dissociation and seem to prevent lattice oxygen to take part in the methane oxidation. The main catalytic action is thus proposed to shift from the Mars-van Krevelen mechanism in dry conditions to a slower route that relies on Langmuir-Hinshelwood type of steps in wet conditions. This key finding has clear implications on catalyst design for low-temperature gas combustion emission control

Chasing PtOx species in ceria supported platinum during CO oxidation extinction with correlative operando spectroscopic techniques

Industrially relevant, highly dispersed, Pt/ceria and reference Pt/alumina catalysts with narrow Pt particle size distributions have been prepared, characterised ex situ and studied for CO oxidation by operando infrared and X-ray absorption spectroscopy. At high CO conversions, spectator CO ad-species on ionic platinum are observed while the CO oxidation proceeds on Pt particles in a high oxidation state exhibiting significant Pt[sbnd]O coordination. During the protracted catalytic extinction, the CO coverage builds up gradually while the Pt oxidation state and Pt[sbnd]O coordination remain high because of interactions with ceria. The observed CO oxidation at high CO coverage is suggested to involve sites at the platinum-ceria boundary that cannot be CO self-poisoned. This behaviour is in stark contrast to that of Pt/alumina, which shows removal of platinum oxides formed during CO oxidation and the classical drop in catalytic activity caused by rapid CO self-poisoning when reaching a critical temperature

Methane Adsorption and Methanol Desorption for Copper Modified Boron Silicate

Boron silicate (BS) with a chabazite framework structure was synthesised using a direct route and rigorously characterized before it was ion-exchanged with copper to form Cu-BS. Employing in situ infrared spectroscopy, we show that Cu-BS is capable of oxidising methane to methoxy species and methanol interacts with the boron sites without deprotonation

Cardiovascular disease, chronic kidney disease, and diabetes mortality burden of cardiometabolic risk factors from 1980 to 2010: A comparative risk assessment

Background: High blood pressure, blood glucose, serum cholesterol, and BMI are risk factors for cardiovascular diseases and some of these factors also increase the risk of chronic kidney disease and diabetes. We estimated mortality from cardiovascular diseases, chronic kidney disease, and diabetes that was attributable to these four cardiometabolic risk factors for all countries and regions from 1980 to 2010. Methods: We used data for exposure to risk factors by country, age group, and sex from pooled analyses of population-based health surveys. We obtained relative risks for the effects of risk factors on cause-specific mortality from meta-analyses of large prospective studies. We calculated the population attributable fractions for each risk factor alone, and for the combination of all risk factors, accounting for multicausality and for mediation of the effects of BMI by the other three risks. We calculated attributable deaths by multiplying the cause-specific population attributable fractions by the number of disease-specific deaths. We obtained cause-specific mortality from the Global Burden of Diseases, Injuries, and Risk Factors 2010 Study. We propagated the uncertainties of all the inputs to the final estimates. Findings: In 2010, high blood pressure was the leading risk factor for deaths due to cardiovascular diseases, chronic kidney disease, and diabetes in every region, causing more than 40% of worldwide deaths from these diseases; high BMI and glucose were each responsible for about 15% of deaths, and high cholesterol for more than 10%. After accounting for multicausality, 63% (10·8 million deaths, 95% CI 10·1-11·5) of deaths from these diseases in 2010 were attributable to the combined effect of these four metabolic risk factors, compared with 67% (7·1 million deaths, 6·6-7·6) in 1980. The mortality burden of high BMI and glucose nearly doubled from 1980 to 2010. At the country level, age-standardised death rates from these diseases attributable to the combined effects of these four risk factors surpassed 925 deaths per 100 000 for men in Belarus, Kazakhstan, and Mongolia, but were less than 130 deaths per 100 000 for women and less than 200 for men in some high-income countries including Australia, Canada, France, Japan, the Netherlands, Singapore, South Korea, and Spain. Interpretation: The salient features of the cardiometabolic disease and risk factor epidemic at the beginning of the 21st century are high blood pressure and an increasing effect of obesity and diabetes. The mortality burden of cardiometabolic risk factors has shifted from high-income to low-income and middle-income countries. Lowering cardiometabolic risks through dietary, behavioural, and pharmacological interventions should be a part of the global response to non-communicable diseases. Funding: UK Medical Research Council, US National Institutes of Health. © 2014 Elsevier Ltd

Alcohol use in adolescence and risk of disability pension: a 39 year follow-up of a population-based conscription survey.

BACKGROUND: The role of alcohol consumption for disability pension (DP) is controversial and systematic reviews have not established causality. We aimed to assess the role of adolescent alcohol use for future DP. We wanted to find out whether an increased risk mainly would affect DP occurring early or late in life as well as whether the level of alcohol consumption and patterns of drinking contribute differently in DP receiving. METHODOLOGY/PRINCIPAL FINDINGS: The study is a 39-year follow-up of 49 321 Swedish men born in 1949-1951 and conscripted for compulsory military service in 1969-1970. As study exposures (i) "risk use" of alcohol composed of measures related to pattern of drinking, and (ii) the level of consumption based on self-reported volume and frequency of drinking had been used. Information on DP was obtained from social insurance databases through 2008. "Risk use" of alcohol was associated with both "early DP" and "late DP", i.e. granted below and above the approximate age of 40 years, with crude hazard ratio (HR) of 2.89 (95% confidence intervals (CI) 2.47-3.38) and HR of 1.87 (95%CI: 1.74-2.02), respectively. After adjustment for covariates, HR was reduced to 1.32 (95%CI: 1.09-1.59) and 1.14 (95%CI: 1.05-1.25), respectively. Similar patterns were seen for moderate (101-250 g 100% alcohol/week) and high (>250 g) consumption, though the risk disappeared when fully adjusted. CONCLUSIONS/SIGNIFICANCE: Alcohol use in adolescence, particularly measured as "risk use", is associated with increased risk of future DP. The association is stronger for "early DP", but remains significant even for DP granted in older ages. Therefore, pattern of drinking in adolescent should be considered an important marker for future reduced work capacity

Weight loss, adverse events, and loss to follow-up after gastric bypass in young versus older adults : A Scandinavian Obesity Surgery Registry study.

BACKGROUND: Young adults display particularly poor weight loss in behavioral obesity treatment; nonetheless, they have seldom been included in bariatric research. OBJECTIVES: To compare weight loss, adverse events, and loss to follow-up in young (18-25 yr) versus older (≥26 yr) adults up to 5 years after Roux-en-Y gastric bypass. SETTING: Nationwide, register-based study, Sweden. METHODS: Prospective registry data (Scandinavian Obesity Surgery Register) were analyzed in young (22.2 yr [standard deviation (SD): 2.1], 81.6% women, mean body mass index 43.7 kg/m2 [SD: 5.4]) and older (42.6 years [SD: 9.6], 82.0% women, mean body mass index 43.4 kg/m2 [SD: 5.0]) adults undergoing Roux-en-Y gastric bypass. Groups were matched for body mass index, sex, and year of surgery. Regression analyses and mixed models were used to compare outcomes between groups. RESULTS: A total of 369 young (37.0% of eligible) and 2210 older (46.1%) adults attended the 5-year follow-up. At this time, weight loss was 31.8% in young and 28.2% in older adults (P < .001), with a serious adverse event (Clavien-Dindo ≥3b) being reported in 52 (14.1%) young and 153 (6.9%) older adults (odds ratio = 2.06, 95% confidence interval: 1.45-2.92, P < .001). Loss to follow-up was higher in young versus older adults throughout the study period (range of relative risk = 1.16-1.89, P < .001). CONCLUSIONS: While young adults displayed at least equal weight loss as older adults, rates of adverse events were approximately doubled, and loss to follow-up rates were higher. Future studies on the significance of and the etiology behind the higher incidence of serious adverse events are needed. Intensified clinical contact post Roux-en-Y gastric bypass should have the potential to further improve outcomes in young adults