Development of biofuel cells based on gold nanoparticle decorated multi-walled carbon nanotubes

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 (∼1.3 V). 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.

► The thermal treatment activated Au-NPs on f-MWCNTs for monosaccharide oxidation reactions was first time studied.
► The air-glucose fuel cell prototype using Au-NPs/f-MWCNTs had an outstandingly high open circuit voltage (1.3 V).
► The catalytic efficiency and stability of Au-NPs/f-MWCNTs were confirmed to be superior to those of the Au sheet.
► The different configuration of –OH groups at C2 and C3 is crucial to enhanced monosaccharide oxidation current.