Optimizing the nickel boride layer thickness in a spectroelectrochemical ATR-FTIR thin-film flow cell applied in glycerol oxidation

The influence of the drop-casted nickel boride catalyst loading on glassy carbon electrodes was investigated in a spectroelectrochemical ATR-FTIR thin-film flow cell applied in alkaline glycerol electrooxidation.The continuously operated radial flow cell consisted of a borehole electrode positioned 50μm above an internal reflection element enabling operando FTIR spectroscopy.It is identified as a suitable tool for facile and reproducible screening of electrocatalysts under well-defined conditions,additionally providing access to the selectivities in complex reaction networks such as glycerol oxidation.The fast product identification by ATR-IR spectroscopy was validated by the more time-consuming quantitative HPLC analysis of the pumped electrolyte.High degrees of glycerol conversion were achieved under the applied laminar flow conditions using 0.1 M glycerol and 1 M KOH in water and a flow rate of 5μL min^(–1).Conversion and selectivity were found to depend on the catalyst loading,which determined the catalyst layer thickness and roughness.The highest loading of 210μg cm^(–2)resulted in 73%conversion and a higher formate selectivity of almost 80%,which is ascribed to longer residence times in rougher films favoring readsorption and C–C bond scission.The lowest loading of 13μg cm^(–2)was sufficient to reach 63%conversion,a lower formate selectivity of 60%,and,correspondingly,higher selectivities of C_(2)species such as glycolate amounting to 8%.Thus,only low catalyst loadings resulting in very thin films in the fewμm thickness range are suitable for reliable catalyst screening.

Fe/Co and Ni/Co-pentlandite type electrocatalysts for the hydrogen evolution reaction

Metal-rich transition metal sulfides recently gained increasing attention as electrocatalysts for the hydrogen evolution reaction(HER),as they are capable to overcome major challenges faced by sulfide-rich metal catalysts such as limited conductivity and the necessity of nanostructuring.Herein,we present the synthesis,characterization and electrocatalytic investigation of ternary metal-rich sulfide composites FexCo9-xS8 as well as Ni_(y)Co_(9-y)S_(8)(x=y=0-4.5),which possess pentlandite-type structures.In this study,we show a stepwise alteration of the binary cobalt pentlandite Co9S8 and report on the replacement of cobalt with up to 4.5 equivalents of either iron or nickel.These altered pentlandite composites facilitate the proton reduction in acidic media at different temperatures.We furthermore show that the stoichiometric variation has a decisive influence on the electrochemical activation/deactivation behavior of the catalysts under reductive electrocatalytic conditions.Here,Co-deficient composites display an improved HER performance in contrast to Co_(9)S_(8).Notably,Ni/Co compounds generally tend to show higher catalytic activities towards HER than their respective Fe/Co compounds.

On the role of cobalt carbidization in higher alcohol synthesis over hydrotalcite-based Co-Cu catalysts

Co-Cu-based catalysts are widely applied in higher alcohol synthesis (HAS) from synthesis gas. Although the nature of the active sites is still not fully understood, the formation of Co2C under HAS conditions seems to play a major role. A CO pretreatment procedure was developed allowing a systematic investigation of the influence of cobalt carbidization on the structural properties and catalytic performance of the catalysts. By exposing the catalyst to a CO-containing atmosphere prior to HAS, Co enrichment of the catalyst surface occurred followed by carbide formation. This surface modification decreased the formation of hydrocarbons and enhanced the formation of C2+OH. The catalyst pretreated with CO at 20 bar achieved the highest selectivity to ethanol and the lowest hydrocarbon selectivity.

Recombinant human erythropoietin counteracts cisplatin-induced visceral hyperalgesia

Objective Cisplatin exerts its cytotoxic effect through distinct DNA lesions,leading to peripheral neuropathy.The risk of sensory neuropathy is a common problem during cancer treatment with cisplatin,leading to somatic hyperalgesia.Yet,data focussing on cisplatin-induced impairment of the autonomic nervous system are limited.The present study was aimed to investigate the effect of recombinant human erythropoietin（rhEPO）on cisplatin-induced visceral hyperalgesia.Methods C57BL/6 mice were treated either with cisplatin（2 mg/kg,once per week）or with cisplatin（2 mg/kg,once per week）plus rhEPO （40μg/kg,3 times per week）for 8 weeks.Controls were treated with saline.To quantify the visceromotor response（VMR）at week 9,standardized electrodes were implanted into the external oblique musculature for electromyographic recordings.After that,animals were decapitated and dorsal root ganglia（DRG）was removed for transmission electron microscopy studies.Results Cisplatin-treated mice showed a significant increase of VMR compared to the controls[（7080±969）vs（2864±279）;P0.001],while rhEPO dramatically counteracted this effect[（2962±336）vs（7080±969）;P0.001）].Transmission electron microscopy revealed cisplatin-induced structural lesions of nuclear membrane in DRG cells,which could be ameliorated by rhEPO.Conclusion Erythropoietin can significantly ameliorate the cisplatin-induced visceral hyperplasia and DRG nuclear membrane structure damage in mice,indicating a neuroprotective role of erythropoietin.