Reactions of ethanol over CeO2 and Ru/CeO2 catalysts

The reaction of ethanol has been investigated on Ru/CeO2 in steady state conditions as well as with temperature programmed desorption (TPD). High resolution transmission electron microscopy (HRTEM) images indicated that the used catalyst contained Ru particles with a mean size of ca. 1.5 nm well dispersed on CeO2 (of about 12–15 nm in size). Surface uptake of ethanol was measured by changing exposure to ethanol followed by TPD. Saturation coverage is found to be between 0.25 and 0.33 of a monolayer for CeO2 that has been prior heated with O2 at 773 K. The main reactions of ethanol on CeO2 during TPD are: re-combinative desorption of ethanol; dehydrogenation to acetaldehyde; and dehydration to ethylene. The dehydration to ethylene occurs mainly in a small temperature window at about 700 K and it is attributed to ethoxides adsorbed on surface-oxygen defects. The presence of Ru considerably modified the reaction of ceria towards ethanol. It has switched the desorption products to CO, CO2, CH4 and H2. These latter products are typical reforming products. Ethanol steam reforming (ESR) conducted on Ru/CeO2 indicated that optimal reaction activity is at about 673 K above which CO2 production declines (together with that of H2) due to reverse water gas shift. This trend was well captured during ethanol TPD where CO2 desorbed about 50 K below than CO on both oxidized and reduced Ru/CeO2 catalysts.Peer ReviewedPostprint (author's final draft

A Stable Integrated Photoelectrochemical Reactor for H₂ Production from Water Attains a Solar‐to‐Hydrogen Efficiency of 18 % at 15 Suns and 13 % at 207 Suns

The major challenge in solar water splitting to H_{2} and O_{2} is in making a stable and affordable system for large‐scale applications. We have designed, fabricated, and tested a photoelectrochemical reactor characterized as follows: 1) it comprises an integrated device to reduce the balance of the system cost, 2) it utilizes concentrated sunlight to reduce the photoabsorber cost, and 3) it employs and alkaline electrolyte to reduce catalyst cost and eliminate external thermal management needs. The system consists of an III‐V‐based photovoltaic cell integrated with Ni foil as an O_{2} evolution catalyst that also protects the cell from corrosion. At low light concentration, without the use of optical lenses, the solar‐to‐hydrogen (STH) efficiency was 18.3 %, while at high light concentration (up to 207 suns) with the use of optical lenses, the STH efficiency was 13 %. Catalytic tests conducted for over 100 hours at 100–200 suns showed no sign of degradation nor deviation from product stoichiometry (H_{2}/O_{2}=2). Further tests projected a system stability of years

Priming of prosopis cineraria (L.) druce and acacia tortilis (forssk) seeds with fulvic acid extracted from compost to improve germination and seedling vigor

Composting of waste plant materials and its use in agriculture and landscape sites is an environmental friendly way of reducing waste material and conserving the environment. In this perspectives a survey has been performed at the Dubai based International Center for Biosaline Agriculture to compost the plants based waste material (lawn cuttings-grass) to compost. The material was inoculated with a consortium of microbes leading to form stable and mature compost with high organic matter (38%). In order to conduct seed germination tests, Fulvic acid was extracted from the compost. A pot experiment was conducted over a period of 30 days in the green house to study the effect of Fulvic acid on the seed germination, and plant growth of Prosopis cineraria (L.) Druce (Ghaff) and Acacia tortilis (Forssk.) Hayne. Seeds of both trees were treated with Fulvic acid at 0.5% and 1% and water treatment was used as control. Generally seed germination and biomass were increased at both rates of fulvic acid. However, a pronounced increase was found in seed germination when fulvic acid was used at 1.0% (Prosopis cineraria 27%; Acacia tortilis 20% increase over control). Similarly biomass (shoot and root) of A. tortilis and P. cineraria was increase 34% and 94% respectively

Sustainable food production in marginal lands—Case of GDLA member countries

Sustainable food production in the changing climate and dwindling water resources in the Global Dry Land Alliance (GDLA) member countries is a real challenge, especially when considering marginal lands in dryland systems. The definition of marginal land is very vague and defined from different perspectives (pragmatism about marginal lands). Dryland itself indicates "marginality" due to water stress. In general, the abandoned agriculture land where food production is not economical, and has low inherent productivity potential is considered marginal; however, a land may be marginal for agriculture but vital for grazing. In this paper attempts have been made to give review of literature (water stress, extent of marginal saline lands, marginality). Policy matters (development of soil, water and agriculture strategies) that GDLA and member countries should consider for future sustainable food production in their countries, including but not limited to, assessment of land resources for agriculture potential, defining, mapping and characterizing marginal lands, and use of innovative technologies (conservation agriculture, climate smart agriculture, integrated soil reclamation program and capacity building) for food production, are discussed. The international perception (FAO, UNEP, CGIAR) on marginal lands is also described. An innovative approach of using national biocapacity and ecological footprint is used to assess marginality of GDLA member countries. Ecological overshoot (using 1.5 earth planets) and biocapacity debtor and creditor countries are highlighted. Challenges and best management practices for food production in marginal lands are included. Other important issues, like leasing land abroad, GDLA strategic food reserves and best management practices, innovative ideas for food production are shared. Finally recommendations are drafted for actions by GDLA, its member countries and the partners

Development of a Lebanese food exchange system based on frequently consumed Eastern Mediterranean traditional dishes and Arabic sweets

The aim of this project was to convert the recipes of the Lebanese traditional dishes and Arabic sweets into meal planning exchange lists whose items are expressed in grams and adjusted to Lebanese household measures (cups and spoons) that could be used by healthcare professionals

Reactions of ethanol over CeO2 and Ru/CeO2 catalysts

The reaction of ethanol has been investigated on Ru/CeO2 in steady state conditions as well as with temperature programmed desorption (TPD). High resolution transmission electron microscopy (HRTEM) images indicated that the used catalyst contained Ru particles with a mean size of ca. 1.5 nm well dispersed on CeO2 (of about 12–15 nm in size). Surface uptake of ethanol was measured by changing exposure to ethanol followed by TPD. Saturation coverage is found to be between 0.25 and 0.33 of a monolayer for CeO2 that has been prior heated with O2 at 773 K. The main reactions of ethanol on CeO2 during TPD are: re-combinative desorption of ethanol; dehydrogenation to acetaldehyde; and dehydration to ethylene. The dehydration to ethylene occurs mainly in a small temperature window at about 700 K and it is attributed to ethoxides adsorbed on surface-oxygen defects. The presence of Ru considerably modified the reaction of ceria towards ethanol. It has switched the desorption products to CO, CO2, CH4 and H2. These latter products are typical reforming products. Ethanol steam reforming (ESR) conducted on Ru/CeO2 indicated that optimal reaction activity is at about 673 K above which CO2 production declines (together with that of H2) due to reverse water gas shift. This trend was well captured during ethanol TPD where CO2 desorbed about 50 K below than CO on both oxidized and reduced Ru/CeO2 catalysts.Peer Reviewe