Effect of Surface Pt Doping on the Reactivity of Au(111) Surfaces towards Methanol Dehydrogenation: A First-Principles Density Functional Theory Investigation.

The surprisingly high catalytic activity of gold has been known to the heterogeneous catalysis community since the mid-1980s. Significant efforts have been directed towards improving the reactivity of these surfaces towards important industrial reactions. One such strategy is the introduction of small amounts of other metals to create Au-based surface alloys. In this work, we investigated the synergistic effect of the Pt doping of a Au(111) surface on decreasing the activation barrier of the methanol dehydrogenation elementary step within first-principles density functional theory. To this end, we constructed several models of Pt-doped Au(111) surfaces, including a full Pt overlayer and monolayer. The effect of Pt surface doping was then investigated via the computation of the adsorption energies of the various chemical species involved in the catalytic step and the estimation of the activation barriers of methanol dehydrogenation. Both the electronic and strain effects induced by Pt surface doping substantially lowered the activation energy barrier of this important elementary reaction step. Moreover, in the presence of preadsorbed atomic oxygen, Pt surface doping could be used to reduce the activation energy for methanol dehydrogenation to as low as 0.1 eV.

Building an Iron Chromophore Incorporating Prussian Blue Analogue for Photoelectrochemical Water Oxidation.

Invited for the cover of this issue is the Ferdi Karadas and Ekmel Ozbay groups at Bilkent University and co-workers. The image presents an utopic city in Iron Age, which is powered by an iron photosensitizer that bridges semiconductor buildings (TiO2 nanowires) and the catalyst (cobalt site). Read the full text of the article at 10.1002/chem.202100654.

Building an Iron Chromophore Incorporating Prussian Blue Analogue for Photoelectrochemical Water Oxidation.

The replacement of traditional ruthenium-based photosensitizers with low-cost and abundant iron analogs is a key step for the advancement of scalable and sustainable dye-sensitized water splitting cells. In this proof-of-concept study, a pyridinium ligand coordinated pentacyanoferrate(II) chromophore is used to construct a cyanide-based CoFe extended bulk framework, in which the iron photosensitizer units are connected to cobalt water oxidation catalytic sites through cyanide linkers. The iron-sensitized photoanode exhibits exceptional stability for at least 5 h at pH 7 and features its photosensitizing ability with an incident photon-to-current conversion capacity up to 500 nm with nanosecond scale excited state lifetime. Ultrafast transient absorption and computational studies reveal that iron and cobalt sites mutually support each other for charge separation via short bridging cyanide groups and for injection to the semiconductor in our proof-of-concept photoelectrochemical device. The reorganization of the excited states due to the mixing of electronic states of metal-based orbitals subsequently tailor the electron transfer cascade during the photoelectrochemical process. This breakthrough in chromophore-catalyst assemblies will spark interest in dye-sensitization with robust bulk systems for photoconversion applications.

Emotion dysregulation and pediatric obesity: investigating the role of Internet addiction and eating behaviors on this relationship in an adolescent sample.

OBJECTIVE: The first aim was to investigate whether there was a mediator role of Internet addiction or uncontrolled/emotional eating on the association between emotion dysregulation and body mass index-standard deviation score (BMI-SDS). The second aim was to detect which of these variables (emotion dysregulation, Internet addiction, and uncontrolled/emotional eating) significantly affect the presence of obesity (OB). METHODS: A total of 123 adolescents (OB (n = 65, 57% of girls, mean age = 15 ± 1.9, BMI percentile between 95 and 99) and healthy control (HC) (n = 58; 53% of girls, mean age = 15.5 ± 1.8, BMI percentile between 1 and 84) aged between 11 and 18 were recruited. Difficulties in Emotion Regulation Scale (DERS) and Internet Addiction Test (IAT) were completed by adolescents. Uncontrolled and emotional eating behaviors were measured by Three Factors Eating Questionnaire (TFE-Q)'s sub-domains. RESULTS: There was no significant direct effect of DERS on BMI-SDS, whereas the indirect effect of DERS on BMI-SDS which was mediated by both IAT and TFE-Q was statistically significant. In logistic regression analysis, an increase by 1 point in DERS total score escalated the odds of being OB by 2%. Moreover, a 22-fold increased risk of OB has been detected in moderate/severe Internet addiction compared to no addiction. CONCLUSION: This cross-sectional study showed that the association between emotion dysregulation and BMI-SDS was totally mediated by internet addiction and uncontrolled/emotional eating. In addition, emotion dysregulation and Internet addiction were significant determinants of OB. A prospective study is needed to detect the causal relationship between these variables. LEVEL OF EVIDENCE: Level III, case-control analytic study.

Effect of Platinum, Gold, and Potassium Additives on the Surface Chemistry of CdI2-Antitype Mo2C.

Transition metal carbides are versatile materials for diverse industrial applications including catalysis, where their relatively low cost is very attractive. In this work, we present a rather extensive density functional theory study on the energetics of adsorption of a selection of atomic and molecular species on two Mo terminations of the CdI2 antitype phase of Mo2C. Moreover, the coadsorption of CO in the presence of preadsorbed metal atoms and its dissociative adsorption in the absence and presence of preadsorbed Pt and K were investigated. By using CO as a probe to understand the structural/electronic effects of the preadsorption of the metal atoms on the Mo2C(001) surface, we showed that K further enhances CO adsorption/activation on the surface, in contrast to the precious metals considered. Moreover, it was observed that the presence of both Pt and K stabilizes the transition state for the C-O bond dissociation, lowering the activation barrier for the dissociation of the C-O bond by about 0.3 and 0.4 eV, respectively.