Search

Abstract: A Pt/C electrocatalyst was prepared from colloidal Pt nanoparticles stabilised by Nafion. This electrocatalyst was found to exhibit negligible degradation under a potential cycling regime conducted on a model thin-film catalyst layer in a 3-electrode cell set-up, in which an E-Tek Pt/C commercial catalyst showed a 23% loss of specific electrochemical surface area (SECSA). The enhanced durability of the Nafion-derived is thought to arise from the protection of Pt particles against dissolution and sintering by the surrounding Nafion layer. The use of the ionomer phase as a protective agent in the catalyst layer presents a novel strategy for the production of more durable Pt/C catalysts for the Proton Exchange Membrane Fuel Cell (PEMFC), which currently presents a significant challenge for the commercialisation of this technology. [Copyright &y& Elsevier]

The commercialisation of polymer electrolyte fuel cells (PEFCs) has been hampered by the high cost of platinum metal. Due to its high durability and catalytic activity, platinum is widely used to catalyse the oxygen reduction and hydrogen oxidation reactions essential to the operation of these cells. Core@shell nanoparticles with thin layers of platinum deposited on cores composed of cheaper materials have offered an attractive route towards the reduction of overall loading of platinum, with the retention of active catalyst surface area. This review surveys approaches taken to prepare idealised active and durable core@shell nanocatalysts by tweaking core compositions. A critical reflection on the current status of the field, as well as predictions as to likely directions for future developments, are discussed as a conclusion to the review. [ABSTRACT FROM AUTHOR]

Charge interactions play a critical role in the activation of the innate immune system by damage- and pathogen-associated molecular pattern receptors. The ability of these receptors to recognize a wide spectrum of ligands through a common mechanism is critical in host defense. In this article, we argue that platelet glycoprotein receptors that signal through conserved tyrosine-based motifs function as pattern recognition receptors (PRRs) for charged endogenous and exogenous ligands, including sulfated polysaccharides, charged proteins and nanoparticles. This is exemplified by GPVI, CLEC-2 and PEAR1 which are activated by a wide spectrum of endogenous and exogenous ligands, including diesel exhaust particles, sulfated polysaccharides and charged surfaces. We propose that this mechanism has evolved to drive rapid activation of platelets at sites of injury, but that under some conditions it can drive occlusive thrombosis, for example, when blood comes into contact with infectious agents or toxins. In this Opinion Article, we discuss mechanisms behind charge-mediated platelet activation and opportunities for designing nanoparticles and related agents such as dendrimers as novel antithrombotics. [ABSTRACT FROM AUTHOR]