Proton-Coupled Oxygen Reduction at Liquid-Liquid Interfaces Catalyzed by Cobalt Porphine

Cobalt porphine (CoP) dissolved in the organic phase of a biphasic system is used to catalyze O2 reduction by an electron donor, ferrocene (Fc). Using voltammetry at the interface between two immiscible electrolyte solutions (ITIES), it is possible to drive this catalytic reduction at the interface as a function of the applied potential difference, where aqueous protons and organic electron donors combine to reduce O2. The current signal observed corresponds to a proton-coupled electron transfer (PCET) reaction, as no current and no reaction can be observed in the absence of either the aqueous acid, CoP, Fc, or O2

A fluidic device for the controlled formation and real-time monitoring of soft membranes self-assembled at liquid interfaces

The work was supported by the European Research Council Starting Grant (STROFUNSCAFF) and the Marie Curie Career Integration Grant (BIOMORPH). L.B. acknowledges fnancial support from the European Community through grant no. 618335 ‘FlowMat: Flow and Capillarity in Materials Science’ and ERC Starting Grant FLEXNANOFLOW no. 715475. Te authors thank Karla E. Inostroza-Brito for the constructive support in this work

Simple and clear evidence for positive feedback limitation by bipolar behavior during scanning electrochemical microscopy of unbiased conductors

On the basis of an experimentally validated simple theoretical model, it is demonstrated unambiguously that when an unbiased conductor is probed by a scanning electrochemical tip (scanning electrochemical microscopy, SECM), it performs as a bipolar electrode. Though already envisioned in most recent SECM theories, this phenomenon is generally overlooked in SECM experimental investigations. However, as is shown here, this may alter significantly positive feedback measurements when the probed conductor is not much larger than the ti

Catalytic hydrogen evolution by molybdenum-based ternary metal sulfide nanoparticles

The search for highly active earth-abundant elements and nonexpensive catalysts for hydrogen evolution reaction is a vital and demanding task to minimize energy consumption. Transition metals incorporated into molybdenum sulfides are promising candidates for hydrogen evolution because of their unique chemical and physical properties. Here, we first describe a general strategy for the synthesis of particle-shaped molybdenum-based ternary refractory metal sulfides (MMoSx; M = Fe, Co, Ni, and Mn) through a simple hot-injection method. The newly developed materials are affirmed as valuable alternatives to noble-metal platinum because of their simple fabrication, inexpensiveness, and impressive catalytic performance. We present highly efficient catalysts for hydrogen evolution at a polarized water/1,2-dichloroethane interface by using decamethylferrocene (DMFc). The kinetics of hydrogen evolution studies are monitored by two-phase reactions using UV-vis spectroscopy and also further proven by gas chromotography. These ternary refractory metal sulfide catalysts show high catalytic activities upon hydrogen evolution comparable to platinum. The rate of hydrogen evolution for the MMoSx catalysts changed in the order Ni > Co > Fe > Mn according to the types of first-row transition metals.Firat University Scientific Research Projects Management Unit: 17201020 Türkiye Bilimler Akademisi Türkiye Bilimsel ve Teknolojik Araştirma Kurumu: 215M309The authors thank The Scientific and Technological Research Council of Turkey (Grant 215M309), UNESCO-Loreal for Woman in Science Program, Selcuk University Scientific Research Projects (Grant 17201020), and Turkish Academy of Sciences via a TUBA-GEBIP fellowship for supporting this work. This paper is part of the Ph.D. thesis prepared by E.A

Molecular electrocatalysis for oxygen reduction by cobalt porphyrins adsorbed at liquid/liquid interfaces

Molecular electrocatalysis for oxygen reduction at a polarized water/1,2-dichloroethane (DCE) interface was studied, involving aqueous protons, ferrocene (Fc) in DCE and amphiphilic cobalt porphyrin catalysts adsorbed at the interface. The catalyst, (2,8,13,17-tetraethyl-3,7,12,18-tetramethyl-5-p-aminophenylporphyrin) cobalt(II) (CoAP), functions like conventional cobalt porphyrins, activating O2 via coordination by the formation of a superoxide structure. Furthermore, due to the hydrophilic nature of the aminophenyl group, CoAP has a strong affinity for the water/DCE interface as evidenced by lipophilicity mapping calculations and surface tension measurements, facilitating the protonation of the CoAP-O2 complex and its reduction by ferrocene. The reaction is electrocatalytic as its rate depends on the applied Galvani potential difference between the two phases