Investigations of mechanism, surface species and support effects in CO hydrogenation over Rh

The Rh-catalyzed CO hydrogenation to hydrocarbons and C$_{2}$-oxygenates over Rh/ZrO$_{2}$ and Rh/SiO$_{2}$ was studied. Catalytic reaction tests show a support effect with a faster steady state reaction rate over Rh/ZrO$_{2}$ compared to Rh/SiO$_{2}$. Temperature programmed hydrogenation (TPH) experiments reveal that the CO dissociation on the metal surface is rate limiting, and the support effect thus accelerates the CO dissociation on the metal. Combined TPH and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) studies after low-temperature CO pre-adsorption reveal a H-assisted C-O bond breakage through CH$_{3}$O species on the Rh surface. Transient measurements indicate that this mechanism is also likely to be in operation during the steady state reaction at higher temperatures, although here the methoxide is too short-lived to be detected at steady state. This hydrogen-assisted CO activation can help to explain that previous studies have observed an inverse H/D isotope effect for Rh despite CO dissociation being the rate limiting step. TPH studies show that both CO pre-adsorption at 30 ℃ and CO/H$_{2}$ exposure at 250 ℃ lead to so high CO coverages that it restricts the CO activation, which only starts once part of the CO has desorbed. The near-complete CO coverage on the working Rh surface is restricting the rate, but is essential for the selectivity towards oxygenates. Studies of acetaldehyde conversion in various atmospheres over Rh/SiO$_{2}$ and Rh/ZrO$_{2}$ catalysts show that acetaldehyde decomposes over a bare Rh surface with a rate that greatly exceeds the oxygenate formation rate in CO hydrogenation. In the presence of CO the acetaldehyde decomposition is strongly inhibited. The high CO coverage on the surface of the working Rh catalysts thus prevents oxygenate decomposition and is therefore essential for the ability to produce oxygenated products. The reaction temperature is observed to play a role for the establishment of the high coverage. During exposure to CO/H$_{2}$ at reaction temperatures (>200 ℃) an activated process occurs whereby both the stability and coverage of the CO adlayer increases. This activated stabilization of the CO adlayer shifts the CO activation up in temperature in a subsequent TPH. The results contribute to a fundamental understanding of the reaction mechanism and support effects in the Rh-catalyzed CO hydrogenation, which can assist the formulation of improved Rh-based catalysts. The results, such as the identification of a H-assisted mechanism of CO hydrogenenation via methoxide, could also be of general relevance for the understanding of CO hydrogenation over other metals

Daily electronic monitoring of subjective and objective measures of illness activity in bipolar disorder using smartphones--the MONARCA II trial protocol: a randomized controlled single-blind parallel-group trial

BACKGROUND: Patients with bipolar disorder often show decreased adherence with mood stabilizers and frequently interventions on prodromal depressive and manic symptoms are delayed. Recently, the MONARCA I randomized controlled trial investigated the effect of electronic self-monitoring using smartphones on depressive and manic symptoms. The findings suggested that patients using the MONARCA system had more sustained depressive symptoms than patients using a smartphone for normal communicative purposes, but had fewer manic symptoms during the trial. It is likely that the ability of these self-monitored measures to detect prodromal symptoms of depression and mania may be insufficient compared to automatically generated objective data on measures of illness activity such as phone usage, social activity, physical activity, and mobility. The Monsenso system, for smartphones integrating subjective and objective measures of illness activity was developed and will be tested in the present trial. METHODS: The MONARCA II trial uses a randomized controlled single-blind parallel-group design. Patients with bipolar disorder according to ICD-10 who previously have been treated at the Copenhagen Clinic for Affective Disorder, Denmark are included and randomized to either daily use of the Monsenso system including an feedback loop between patients and clinicians (the intervention group) or to the use of a smartphone for normal communicative purposes (the control group) for a 9-month trial period. The trial was started in September 2014 and recruitment is ongoing. The outcomes are: differences in depressive and manic symptoms; rate of depressive and manic episodes (primary); automatically generated objective data on measures of illness activity; number of days hospitalized; psychosocial functioning (secondary); perceived stress; quality of life; self-rated depressive symptoms; self-rated manic symptoms; recovery; empowerment and adherence to medication (tertiary) between the intervention group and the control group during the trial. Ethical permission has been obtained. Positive, neutral and negative findings will be published. DISCUSSION: If the system is effective in reducing depressive and/or manic symptoms (and other symptoms of bipolar disorder) and the rate of episodes, there will be basis for extending the use to the treatment of bipolar disorder in general and in larger scale. TRIAL REGISTRATION: ClinicalTrials.gov NCT02221336. Registered 26(th) of September 2014