On the electrooxidation of glucose on gold: Towards an electrochemical glucaric acid production as value-added chemical

The electrocatalytic oxidation of glucose to value-added chemicals, such as glucaric acid, has gathered increased interest in recent years. Glucose oxidation is a promising process which has the potential to contribute to establishing renewable resources as alternatives to fossil carbon sources. Herein, we present rotating disk electrode (RDE) studies on polycrystalline gold surfaces and subsequent Koutecký-Levich analysis as a benchmark to expand the understanding of reaction kinetics and competition between glucose, reaction intermediates and OH− at the catalyst surface. Based on the obtained results it follows that the glucose oxidation reaction (GOR) is predominately mass-transport controlled. Combining electrochemical studies and Raman spectroscopy, it is shown that increasing glucose concentrations lead to a delayed oxidation of the gold catalyst surface, presumably by increased consumption rates of Au-hydroxide species

Evolution of a GDE setup: Beyond ambient conditions

Gas diffusion electrode (GDE) setups recently and increasingly received attention as testing platforms for fuel cell catalysts. GDE setups provide realistic reaction conditions while remaining simple and efficient to use. Therefore, GDE setups bridge the gap between rotating disk electrode (RDE) measurements and membrane electrode assembly (MEA) testing. Here, we describe our initial GDE design development to its latest improvements that allow application of high temperatures. We point out experimental challenges we overcame, yet also discuss properly applying our new technique to avoid wrongful use. In particular, we advocate for implementing GDE setups in catalyst stability investigations where the technique so far has been used infrequently

Oxygen Reduction Reaction on Polycrystalline Platinum: On the Activity Enhancing Effect of Polyvinylidene Difluoride

There have been several reports concerning the performance improving properties of additives, such as polyvinylidene difluoride (PVDF), to the membrane or electrocatalyst layer of proton exchange membrane fuel cells (PEMFC). However, it is not clear if the observed performance enhancement is due to kinetic, mass transport, or anion blocking effects of the PVDF. In a previous investigation using a thin-film rotating disk electrode (RDE) approach (of decreased complexity as compared to membrane electrode assembly (MEA) tests), a performance increase for the oxygen reduction reaction (ORR) could be confirmed. However, even in RDE measurements, reactant mass transport in the catalyst layer cannot be neglected. Therefore, in the present study, the influence of PVDF is re-examined by coating polycrystalline bulk Pt electrodes by PVDF and measuring ORR activity. The results on polycrystalline bulk Pt indicate that the effects of PVDF on the reaction kinetics and anion adsorption are limited, and that the observed performance increase on high surface area Pt/C most likely is due to an erroneous estimation of the electrochemical active surface area (ECSA) from CO stripping and Hupd

The gas diffusion electrode setup as a testing platform for evaluating fuel cell catalysts: A comparative RDE‐GDE study

Gas diffusion electrode (GDE) setups have been recently introduced as a new experimental approach to test the performance of fuel cell catalysts under high mass transport conditions, while maintaining the simplicity of rotating disk electrode (RDE) setups. In contrast to experimental RDE protocols, for investigations using GDE setups only few systematic studies have been performed. In literature, different GDE arrangements were demonstrated, for example, with and without an incorporated proton exchange membrane. Herein, we chose a membrane-GDE approach for a comparative RDE–GDE study, where we investigate several commercial standard Pt/C fuel cell catalysts with respect to the oxygen reduction reaction (ORR). Our results demonstrate both the challenges and the strengths of the new fuel cell catalyst testing platform. We highlight the analysis and the optimization of catalyst film parameters. That is, instead of focusing on the intrinsic catalyst ORR activities that are typically derived in RDE investigations, we focus on parameters, such as the catalyst ink recipe, which can be optimized for an individual catalyst in a much simpler manner as compared to the elaborative membrane electrode assembly (MEA) testing. In particular, it is demonstrated that ∼50% improvement in ORR performance can be reached for a particular Pt/C catalyst by changing the Nafion content in the catalyst layer. The study therefore stresses the feasibility of the GDE approach used as an intermediate “testing step” between RDE and MEA tests when developing new fuel cell catalysts

Open Source, Pedagogik och Teknik : rekommendation av pedagogisk OS-programvara

Syftet med denna undersökning är att erhålla relevanta frågeställningar som ska utgöra engrund för att ge en rekommendation på en pedagogisk Open Source-programvara som stödjere-learning. En utvärderingsmodell skapas för att få fram ett relevant resultat baseras på svarenpå dessa frågeställningar. Utvärderingsmodellen tillämpas i en fallstudie för att visa enpraktisk användning av modellen. Det framgår vad som är relevant att tänka på vidinförskaffande av en Open Source-programvara som ska vara så pedagogisk som möjligt

Är det möjligt att bryta stagnationen?

Godkänd; 2009; 20091202 (biem

On the electrooxidation of glucose on gold: towards an electrochemical glucaric acid production as value-added chemical

The electrocatalytic oxidation of glucose to value-added chemicals, such as glucaric acid, has gathered increased interest in recent years. Glucose oxidation is a promising process which has the potential to contribute to establishing renewable resources as alternatives to fossil carbon sources. Herein, we present rotating disk electrode (RDE) studies on polycrystalline gold surfaces and subsequent Koutecký-Levich analysis as a benchmark to expand the understanding of reaction kinetics and competition between glucose, reaction intermediates and OH- at the catalyst surface. Combining electrochemical studies and Raman spectroscopy, it is shown that increasing glucose concentrations lead to a delayed oxidation of the gold catalyst surface, presumably by increased consumption rates of Au-hydroxide species