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H2O2 is a versatile chemical and can be generated by the oxygen reduction reaction (ORR) in proton donor solution in molecular solvents or room temperature ionic liquids (IL). We investigated this reaction at interfaces formed by eleven hydrophobic ILs and acidic aqueous solution as a proton source with decamethylferrocene (DMFc) as an electron donor. H2O2 is generated in colorimetrically detectable amounts in biphasic systems formed by alkyl imidazolium hexafluorophosphate or tetraalkylammonium bis(trifluoromethylsulfonyl)imide ionic liquids. H2O2 fluxes were estimated close to liquid|liquid interface by scanning electrochemical microscopy (SECM). Contrary to the interfaces formed by hydrophobic electrolyte solution in a molecular solvent, H2O2 generation is followed by cation expulsion to the aqueous phase. Weak correlation between the H2O2 flux and the difference between DMFc/DMFc+ redox potential and 2 electron ORR standard potential indicates kinetic control of the reaction.

The development of methods for nanoparticle detection is highly desirable due to their increasing presence in the environment. Recently, we have shown that the electrochemical detection in flow is one of the possible solutions. Here we demonstrate a dramatic improvement of analytical parameters of such detection. The significant enhancement of an amperometric signal resulting from the electrocatalytic oxidation of ascorbic acid (AA) in a negatively charged phenylsulphonated carbon nanoparticle suspension in the millifluidic flow injection analysis system as compared to earlier results (D. Ogończyk, et al., Electrochem. Commun., 2014, 43, 40) is presented. This effect results from the tailoring of electrostatic interactions, e.g. optimization of the supporting electrolyte and AA concentration and/or immobilization of positively charged functionalities at the electrode surface. The sensitivity is improved by almost three orders of magnitude and the limit of detection of carbon nanoparticles is decreased by two orders of magnitude down to 0.001 mg mL(-1).

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Nanoparticles have already found numerous applications and their global production is still increasing. Therefore, the engineered nanoobjects of uncertain toxicity become ubiquitous in the environment and a continuous monitoring of their presence is highly desirable. Here, we demonstrate a continuous electrochemical detection of gold nanoparticles (AuNPs) based on synchronous processes of their electrodissolution and electrocatalysis. This approach is realized by the injection of nanoparticles suspension into the Flow Injection Analysis (FIA) system. The modular structure of FIA system is particularly applicable for carrying out of sequential operations: AuNPs passivation, oxidation of aqueous SO2 and gold. It enables continuous, fast and reproducible gold nanoparticles determination in a wide concentration range: 10−10– 10−7 mol nanoobjects L−1.

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Trace metal impurities are known to severely degrade the performance of silicon solar cells. The effect of Nickel dissolved in dilute cleaning solutions was studied in detail. Clean wafers were exposed to these mixtures.The resulting surface concentration and the effect on carrier lifetime upon thermal oxidation, were found to correlate with a first order relation to the concentration of Ni in the solution.The removal of Nickel from the surface by different cleaning recipes was evaluated and compared using thermal oxidation followed by carrier lifetime measurements.The resulting surface concentration and the effect on carrier lifetime upon thermal oxidation, were found to correlate with a first order relation to the concentration of Nickel in the solution.

The electrochemical behaviour of suspended nanoparticles received some attention recently. Very few studies are performed in the flow system. Here, we have demonstrated that injection of positively charged (with ammonium functionalities) carbon nanoparticles suspension to flowing ascorbic acid solution significantly enhances its chronoamperometric response and can be used for these nanoparticles detection. This is because of electrocatalytic properties of these nanoparticles towards ascorbic acid electrooxidation. The magnitude of the signal depends on the type of flow system and is larger than in the case of suspension of negatively charged nanoparticles. It is also proportional to the concentration of nanoparticles. Their adsorption on the electrode surface plays the crucial role in the electrode process.