High-Utilisation Nanoplatinum Catalyst (Pt@cPIM) Obtained via Vacuum Carbonisation in a Molecularly Rigid Polymer of Intrinsic Microporosity

Polymers of intrinsic microporosity (PIM or here PIM-EA-TB) offer a highly rigid host environment into which hexachloroplatinate(IV) anions are readily adsorbed and vacuum carbonised (at 500 °C) to form active embedded platinum nanoparticles. This process is characterised by electron and optical microscopy, atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and electrochemical methods, which reveal that the PIM microporosity facilitates the assembly of nanoparticles of typically 1.0 to 2.5-nm diameter. It is demonstrated that the resulting carbonised “Pt@cPIM” from drop-cast films of ca. 550-nm average thickness, when prepared on tin-doped indium oxide (ITO), contain not only fully encapsulated but also fully active platinum nanoparticles in an electrically conducting hetero-carbon host. Alternatively, for thinner films (50–250 nm) prepared by spin coating, the particles become more exposed due to additional loss of the carbon host. In contrast to catalyst materials prepared by vacuum-thermolysed hexachloroplatinate(IV) precursor, the platinum nanoparticles within Pt@cPIM retain high surface area, electrochemical activity and high catalyst efficiency due to the molecular rigidity of the host. Data are presented for oxygen reduction, methanol oxidation and glucose oxidation, and in all cases, the high catalyst surface area is linked to excellent catalyst utilisation. Robust transparent platinum-coated electrodes are obtained with reactivity equivalent to bare platinum but with only 1 μg Pt cm−2 (i.e. ~100% active Pt nanoparticle surface is maintained in the carbonised microporous host). [Figure not available: see fulltext.

Electrochemical Behavior of Organics Oxidation on Palladium-Based Nanocatalysts Synthesized from Bromide Anion Exchange

International audiencePalladium-based and gold nanomaterials were synthesized by the so-called "Bromide Anion Exchange" method. This soft and clean synthetic route leads to well dispersed small nanoparticles on carbon support. Accordingly, these nanoscale structures have a high active surface area like 81 m(2) g(-1) for the 20 wt.% Pd/C electrocatalyst. The CO stripping experiments performed in alkaline medium have highlighted the dependence of the CO adsorption mode on palladium. When used as anode for glycerol or glucose electrooxidation in alkaline medium, they exhibit good activities. Moreover, the bimetallic catalysts showed an important improvement of the kinetics at lower potentials when compared to Pd/C. Some added value products like glycerate or glycolate have been detected by chromatographic analysis. These nanomaterials are promising electrodes in fuel or hybrid biofuel cell devices in a cogeneration of high value chemicals and energy process

New Preparation of PdNi/C and PdAg/C Nanocatalysts for Glycerol Electrooxidation in Alkaline Medium

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Facile synthesis of highly active and durable PdM/C (M = Fe, Mn) nanocatalysts for the oxygen reduction reaction in an alkaline medium

International audienceThe efficient design of highly active and durable materials towards the ultimate goal of improving kinetics of the oxygen reduction reaction (ORR), which allow enhanced performance in solid alkaline membrane fuel cells (SAMFCs), remains elusive. Seminal studies have shown that by alloying a noble metal such as palladium to a transition metal, it is possible to tune the electronic and/or bifunctional properties enabling substantial ORR performance to be achieved, thereby designing a costly catalyst. Herein, we address and discuss new findings from deeper ORR investigations at palladium-based nanostructures in an alkaline medium. We exploited and manipulated the straightforward and fast synthesis method, the so-called “Bromide Anion Exchange”, to prepare surfactant-free PdM/C (M = Fe, Mn) nanocatalysts exhibiting unprecedented activity and stability towards ORR. PdFe/C from bromide anion exchange (BAE) enables 40and 4-fold enhancement in terms of exchange current density and kinetic current density and ca. 100 mV gains compared to the polyol microwave-assisted method. After 20 000 cycles of accelerated potential cycling test (APCT), our findings indicate that the present PdM/C bimetallics outperform, to the best of our knowledge, most of the data reported for ORR in alkaline media for Pdbased transition metals. The improved catalytic performances are assigned to the absence of any organic contaminants or protective ligands on their surface and their relatively heterogeneous character comprising nanoalloys and nanowire oxides

Promising electrospun carbon fibers material for abiotic and enzymatic catalysis in hybrid biofuel cell for energy conversion

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Advanced micro-power fuel cell for bionanotechnology application

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