ABSTRACT
Metallic catalyst modification by organic ligands is an emerging catalyst design in enhancing the activity and selectivity of electrocatalytic carbon dioxide (CO2) reactive capture and reduction to value-added fuels. However, a lack of fundamental science on how these ligand-metal interfaces interact with CO2 and key intermediates under working conditions has resulted in a trial-and-error approach for experimental designs. With the aid of density functional theory calculations, we provided a comprehensive mechanism study of CO2 reduction to multicarbon products over aminothiolate-coated copper (Cu) catalysts. Our results indicate that the CO2 reduction performance was closely related to the alkyl chain length, ligand coverage, ligand configuration, and Cu facet. The aminothiolate ligand-Cu interface significantly promoted initial CO2 activation and lowered the activation barrier of carbon-carbon coupling through the organic (nitrogen (N)) and inorganic (Cu) interfacial active sites. Experimentally, the selectivity and partial current density of the multicarbon products over aminothiolate-coated Cu increased by 1.5-fold and 2-fold, respectively, as compared to the pristine Cu at -1.16 VRHE, consistent with our theoretical findings. This work highlights the promising strategy of designing the ligand-metal interface for CO2 reactive capture and conversion to multicarbon products.
ABSTRACT
BACKGROUND: Epileptic children are liable to experience oral health problems either due to the disease itself or medications administered to control the condition. AIM: We aimed to investigate caries experience, gingival health and oro-facial traumatic injuries in a sample of epileptic Egyptian children. DESIGN: A retrospective cohort study was conducted from September 2016 to April 2017 using data from medical records in Children Hospital at Ain Shams University. Dental examination was performed for 100 epileptic children and 80 healthy subjects who matched in age, gender, and socio-economic status. Caries experience was measured using the decayed, missing and filled teeth (DMFT or dmft) index and gingival index (GI) of Loe and Sillness was used to determine gingival health status. Oro-facial injuries were assessed using the WHO classification of trauma. Quantitative data were presented as mean, SD, and 95% CI values. Qualitative data were presented as frequencies and percentages and the significance level was set at P ≤ 0.05. RESULTS: The mean ± SD GI for epileptic children was significantly higher (1.16 ± 0.42) than that of healthy children. (1.01 ± 0.11) Healthy subjects had significantly lower mean dmf index scores 2.2 ± 2.6 compared to epileptic subjects where mean dmf scores were 4.1 ± 2.1. No significant difference, however, was detected between the two groups regarding caries experience in permanent dentition or incidence of oro-facial injuries. CONCLUSIONS: Epileptic children are highly burdened with gingival problems and liable to develop dental caries especially in primary dentition. Oral traumatic injuries, however, are not common complications if seizure attacks are well controlled.
