Atomic Isolation and Anchoring of Commercial Pt/C Nanoparticles, a Promising Pathway for Durable PEMFCs.

This study examines the atomic confinement of commercial Pt/C electrocatalysts. While a high electrocatalytic activity for the oxygen reduction reaction is important for proton-exchange membrane fuel cell (PEMFC) performance, the high stability of the electrocatalyst is essential for real applications under harsh operating conditions. The demands necessitate the development of advanced electrocatalysts that are resistant to corrosion. A combination of diazonium chemistry with Cu electrodeposition permits the selective protection of the carbon surface of the commercial Pt/C to prevent corrosion while improving wettability and ionic transfer. The resulting electrocatalysts exhibit an exceptional ORR stability after accelerated stress testing (AST) with a 250% improvement in comparison with unprotected commercial Pt/C. This novel electrochemical pathway provides a much-needed boost to carbon-based catalytic supports, which still face several stability challenges in energy applications in a harsh environment.

Biofuel cells - Activation of micro- and macro-electronic devices.

The article represents a short conceptual overview of biofuel cell applications, rather than their design and operation. Special attention is given to interfacing enzyme-based biofuel cells with power consuming microelectronic devices. Importance of electronic management of the power extracted from biological sources is emphasized. In addition to several briefly explained examples collected from recent publications, one system demonstrating powering of a standard glucometer with an implantable or wearable biofuel cell is described in details. The opinion on the biofuel cell applications and limitations represents the personal vision of the authors and might be not fully in accordance with the opinions of other experts.

Ca2+-Switchable Glucose Dehydrogenase Associated with Electrochemical/Electronic Interfaces: Applications to Signal-Controlled Power Production and Biomolecular Release.

An artificial Ca2+-regulated PQQ glucose dehydrogenase (PQQ-GDH) enzyme was electrically connected to conducting electrodes and semiconductor interfaces. Direct electron transfer from the enzyme to the conducting electrode support was stimulated by the addition of Ca2+ cations resulting in reversible enzyme activation. A signal-switchable biofuel cell and biomolecular release have been realized using the Ca2+-activated enzyme immobilized on conducting electrodes. Interfacing the signal-switchable enzyme with a semiconductor chip allowed electronic read out of the enzyme ON-OFF states. The developed approach based on the signal-regulated PQQ-GDH enables numerous bioelectrochemical/bioelectronic applications of the developed systems in signal-activated biosensors and biofuel cells, as well as in biomolecular computing/logic systems.