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Graphical abstract Highlights • A parallel thermographic screen allows measurement of particle size and support effects on model planar catalysts. • The turn over frequency (TOF) of an exothermic reaction can be determined simultaneously on 100 catalysts. • The catalytic activity for CO oxidation of titania supported gold with particle sizes 6 > d/nm > 1.5 has been measured. • A monotonic increase in the TOF is observed with decreasing particle diameter (d) which is proportional to ca. d−1.8. • Calculation of the gold surface area evidences a surface specific activity of the gold which increases as ca. d−4. • The steep rise in activity suggests an electronic perturbation of the gold nano-particles by the substrate. Abstract A parallel thermographic screening methodology has been developed which allows the measurements of the particle size and support influences on model planar heterogeneous catalysts. A screening chip was designed and fabricated in order to produce multiple fields of low stress silicon nitride membranes that exhibit low thermal conductivity and heat capacity. The heat generated on supported model catalysts in an exothermic reaction on the membranes was measured using a thermal (infra-red) imaging camera, which in turn provided a measure of the turn over frequency (TOF) for the reaction. The catalytic activity for CO oxidation on titania supported gold model catalysts with varying particle size has been measured on 100 catalysts simultaneously. The reaction has been investigated at 80 °C and 170 °C, and pressures ranging between 0.06 mbar and 1.5 mbar for various O 2 :CO ratios. Under all conditions investigated, a monotonic increase in the TOF is observed with decreasing particle diameter (d) which is proportional to ca. d−1.8 in the range 6 > d/nm > 1.5. This is in the opposite direction to the number of potentially active perimeter sites which increases linearly with increasing particle size on these catalysts. We show that the surface area specific activity of the gold is increasing even more steeply with reduced particle size, and is proportional to ca. d−4. This rate of increase in activity is significantly higher than one would expect by any increase one may expect as a result of more active low co-ordinate sites on the gold. The steep increase in activity is ascribed to an electronic interaction between the substrate and the particle. [ABSTRACT FROM AUTHOR]

Highlights: [•] A high-throughput methodology is used to synthesise and screen PdCu alloys. [•] The expected equilibrium phases of the PdCu alloys were identified using XRD. [•] Pd in Cu results in reversible surface oxidation of Cu and oxide destabilisation. [•] This is a result of bi-functional and electronic effects of Pd in Cu, respectively. [•] The most active catalyst is in a narrow compositional region around 84%at. Cu. [ABSTRACT FROM AUTHOR]

Mercury is a highly toxic element for consumers, but its relation to amino acids and physiology of wild fish is not well known. The main aim of this study was to evaluate how total mercury content (THg) of northern pike (Esox lucius) is related to amino acids and potentially important environmental and biological factors along a climate-productivity gradient of ten subarctic lakes. Linear regression between THg and sixteen amino acids content [nmol mg−1 dry weight] from white dorsal muscle of pike from these lakes were tested. Lastly, a general linear model (GLM) for age-corrected THg was used to test which factors are significantly related to mercury content of pike. There was a positive relationship between THg and proline. Seven out of sixteen analysed amino acids (histidine, threonine, arginine, serine, glutamic acid, glycine, and aspartic acid) were significantly negatively related to warmer and more productive lakes, while THg showed a positive relationship. GLM model indicated higher THg was found in higher trophic level pike with lower cysteine content and inhabiting warmer and more productive lakes with larger catchment containing substantial proportion of peatland area. In general, THg was not only related to the biological and environmental variables but also to amino acid content. [Display omitted] • Amino acids (AA) and total mercury (THg) were measured in pike from subarctic lakes. • Effects of environmental and ecological factors on THg content were tested. • THg content had a significant positive correlation with proline in pike muscle. • Content of seven AA in pike decreased towards warmer and more productive lakes. • THg was related to climate and productivity, catchment, trophic level, and cysteine. [ABSTRACT FROM AUTHOR]