Production of Sustainable Energy by Carbon Nanotube/Platinum Catalyst in Microbial Fuel Cell

Carbon supports on preparing iron-nitrogen dual-doped carbon (Fe-N/C) electrocatalysts for microbial fuel cells: mini-review

Microbial fuel cells (MFCs) are devices that treat sewage and generate electricity. Recent researches have demonstrated that the characteristics of carbon precursors can tremendously influence the performance of the MFC cathode. Carbon nanomaterials with good crystallinity as well as high specific surface area (e.x., graphene and carbon nanotube) can not only accelerate charge transport but also afford a good dispersion of catalytic active components, leading to high MFC performance. On these bases, the preparation of highly-active Fe-N/C catalysts using different carbon substrates are mainly discussed in this review. It is pointed out that increasing the surface area and conductivity as well as elevating the density of active sites to reduce the oxygen reduction overpotential is still the emphasis of the current works. At present, although the researchers have made some progress, the output power density is far from meeting the actual application needs.

Development of platinum supported on single-walled carbon nanotubes by deposition-precipitation for microbial fuel cells

Microbial fuel cells (MFCs) are an ecologically friendly technology that can recover electricity and simultaneously treat wastewater. Among all the influential factors, cathode material and catalyst play a crucial role in electricity production and oxygen reduction. In this study, Pt nanocatalysts deposited on single-walled carbon nanotubes (Pt/SWCNTs) were synthesized by the deposition-precipitation (DP) method under optimal conditions. The results show that DP might be a promising method for the preparation of Pt/SWCNTs due to its simple, cost-effective and time-saving procedure, in addition to being highly efficient at creating small Pt particles (0.9 nm) that were very uniformly distributed. The synthesized Pt/SWCNTs suspension was spray-coated on to carbon cloth and then used as a cathode for MFCs. The electricity generation of MFCs equipped with a Pt/SWCNTs cathode was evaluated in terms of open circuit voltage (0.6954 V), internal resistance (63.3 Ω•m²) and maximum power density (2,022 mW/m²). The chemical oxygen demand removal, biological oxygen demand removal, total dissolved solids removal, total suspended solids removal and silver recovery was satisfactory at 84.5%, 74.0%, 45.7%, 60.0% and 99.0%, respectively. Therefore, Pt/SWCNTs from the DP method was identified as a potential candidate to replace commercial Pt-carbon cloth for MFC cathodes.

Fe/N-doped graphene with rod-like CNTs as an air-cathode catalyst in microbial fuel cells

This work proposes a simple and efficient approach for the formation of short carbon nanotubes (CNTs) on graphene sheets. This paper investigates the effect of heat treatment time on the morphology of CNTs. The mechanism of the growth and disappearance of CNTs are also investigated. Graphene is added into ferric trichloride (FeCl3)-melamine solution to obtain a suspension. The suspension is dried with stirring, followed by a carbonization process under N2 atmosphere, resulting in the formation of CNTs on graphene sheets. The thus-prepared carbon material can be used as a kind of durable and efficient non-precious metal oxygen reduction reaction (ORR) electrocatalyst. The ORR activity of the catalyst with favorable performance is characterized and compared with a commercial Pt/C catalyst. The results show that the ORR electron transfer number of Fe-N/G with CNTs is 3.91 ± 0.02. The Fe-N/G-MFC achieves a maximum power density of 1210 ± 23 mW m-2, which is much higher than Pt/C-MFC (1080 ± 20 mW m-2). It demonstrates that Fe-N/G materials with CNTs can be a type of promising highly efficient catalyst and can enhance ORR performance of MFCs. Besides, the reason for the disappearance of CNTs we investigated in this study may provide some ideas for the study of loading metal oxide catalysts on CNTs.

Carbon nanotube modification of microbial fuel cell electrodes

The use of carbon nanotubes (CNTs) for energy harvesting devices is preferable due to their unique mechanical, thermal, and electrical properties. On the other hand, microbial fuel cells (MFCs) are promising devices to recover carbon-neutral energy from the organic matters, and have been hindered with major setbacks towards commercialization. Nanoengineered CNT-based materials show remarkable electrochemical properties, and therefore have provided routes towards highly effective modification of MFC compartments to ultimately reach the theoretical limits of biomass energy recovery, low-cost power production, and thus the commercialization of MFCs. Moreover, these CNT-based composites offer significant flexibility in the design of MFCs that enable their use for a broad spectrum of applications ranging from scaled-up power generation to medically related devices. This article reviews the recent advances in the modification of MFCs using CNTs and CNT-based composites, and the extent to which each modification route impacts MFC power and current generation.