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Abstract: In this work, we designed various polyaniline (PANI) nanocomposites with platinum (Pt) nanoparticle-decorated multi-walled carbon nanotubes (MWCNTs), employed them as anodic catalysts, and studied their structural assembly effects with regard to enhancing biohydrogen fuel cell performance. Of two proposed structures, the PANI/Pt/MWCNTs multilayer nanocomposites showed superior electrocatalytic activities in the hydrogen oxidation reaction and in fuel cell power density relative to the Pt/MWCNTs@PANI core–shell design. These enhancements were attributed to the active interface formed between the Pt nanoparticles and polyaniline nanofibers, where the higher electronic and ionic conductivities of the thin PANI nanofiber layers in contact with Pt active sites were better than with the PANI bound Pt/MWCNTs. We also investigated the change in the electronic state of the composites and the charge-transfer rate caused by varying the structural assembly. Finally, the role of each catalyst component was examined to understand its individual effect on fuel cell performance and to understand its structural assembly effect on enhanced power density. [Copyright &y& Elsevier]

Abstract: This paper introduces a newly designed biohydrogen fuel cell by integrating a bioreactor for hydrogen production with the anode chamber in a hydrogen fuel cell. Two different composites of platinum nanoparticles decorated on functionalised multi-walled carbon nanotubes (Pt/fMWCNTs) and polyaniline (PANI) were fabricated using the electrochemical polymerisation method and used as anodes. The biohydrogen fuel cell using a thin film of PANI nanofibres deposited on Pt/fMWCNTs/carbon paper as the anode showed much higher power density than the cell using a core–shell structure PANI/Pt/fMWCNTs and Pt/fMWCNTs without PANI based anodes. The structural differences between these two composites and their effects on the interaction with hydrogen gas inside the anode chamber leading to the difference in power density of the fuel cell were also discussed. The maximum power density was 613.5mWm−2, which was obtained at a current density of about 2.55Am−2 with a cell voltage of 0.24V using 20mL single-chamber air-cathode, compact biohydrogen fuel cell. [Copyright &y& Elsevier]

A unique artificial catalyst that mimics the structure of active sites in real enzymes using functionalized carbon nanotubes is presented. This concept will allow for the potential construction of a library of biomimetic catalysts for enzyme active centers, for which the structure–catalysis relationships are well defined. [ABSTRACT FROM AUTHOR]

Abstract: This study focused on developing the synthesis of Au nanoparticle-decorated functionalized multi-walled carbon nanotubes (Au-NPs/f-MWCNTs) for monosaccharide (bio-fuel) oxidation reactions and practical application in air-biofuel cells. We developed a scalable and straightforward method to synthesize Au-NPs/f-MWCNTs which allow us to control the loading and size of the Au-NPs. The Au-NPs/f-MWCNTs exhibited better catalytic activities and stability than the Au sheet and subsequently resulted in a threefold increase in the power density of the air-glucose fuel cell with an exceptionally high open circuit voltage (∼1.3V). The catalytic efficiency was confirmed by high performance liquid chromatography with the superior of the Au-NPs/f-MWCNTs over a bare gold electrode. In addition, the application of this advanced catalyst to other monosaccharide oxidation reactions figured out that the configuration of –OH groups at C2 and C3 of the reactants plays an important role in the initial adsorption process, and thus, affects the required activation energy for further oxidation. The different monosaccharides lead to significantly different fuel cell performances in terms of power density, which coherently corresponds to the difference in the configuration of C2 and C3. Because two small air-glucose fuel cells using Au-NPs/f-MWCNTs can run a LED lamp, further applications of other monosaccharides as fuel in biofuel cells for equivalent required power devices may be possible. [Copyright &y& Elsevier]