Microbial fuel cells (MFCs) are an alternative electricity generating technology and efficient method for removing organic material from wastewater. Their low power densities, however, hinder practical applications. A primary limitation in these systems is the anode. The chemical makeup and surface area of the anode influences bacterial respiration rates and in turn, electricity generation. Some of the highest power densities have been reported using large surface area anodes, but due to variable chemical/physical factors (e.g., solution chemistry, architecture) among these studies, meaningful comparisons are difficult to make. In this work, we compare under identical conditions six micro/nano‐structured anodes in micro‐sized MFCs (47 μL). The six materials investigated include carbon nanotube (CNT), carbon nanofiber (CNF), gold/poly (ϵ‐caprolactone) microfiber (GPM), gold/poly(ϵ‐caprolactone) nanofiber (GPN), planar gold (PG), and conventional carbon paper (CP). The MFCs using three dimensional anode structures (CNT, CNF, GPM, and GPN) exhibited lower internal resistances than the macroscopic CP and two‐dimensional PG anodes. However, those novel anode materials suffered from major issues such as high activation loss and instability for long‐term operation, causing an enduring problem in creating widespread commercial MFC applications. The reported work provides an in‐depth understanding of the interplay between micro‐/nano‐structured anodes and active microbial biofilm, suggesting future directions of those novel anode materials for MFC technologies.
in the present contribution, we report a simple and repeatable process for the synthesis of zinc phosphide on two different substrates, zinc foil and zinc evaporated on molybdenum-coated glass. Zinc phosphide has been an important candidate for optoelectronic applications and has also been explored in the lithium ion batteries. Zinc phosphide is synthesized from earth-abundant constituents, zinc and phosphorous. Trioctylphosphine (TOP) is used as a source of phosphorous which reacts with zinc and results in the growth of zinc phosphide. Zinc phosphide has been successfully synthesized in both continuous thin film and nanowires form around ~ 350°C. The synthesized zinc phosphide phase was characterized using SEM, EDS, XRD and XPS. Possible growth mechanism is discussed.
Pyrite phase of FeS2 has attracted substantial attention in the field of thin film solar technology because of its high optical absorption coefficient (~5 x 105 cm-1 at hν > 1.3eV) and the band gap of 0.95 eV. In this research, we have grown highly pure iron pyrite films using a low temperature atmospheric pressure chemical vapor deposition technique. The synthesis temperature is in the range of 375-400°C and Di-tert-butyl disulfide (TBDS) is used as the sulfur precursor. TBDS is a safe and low cost sulfur source unlike H2S, which is highly toxic and requires extreme care in handling. The films obtained were uniform and free from common impurity phases such as troilite and marcasite. The FeS2 films grown earlier with CVD synthesis and sulfurized using H2S had pinholes and contained secondary phases like marcasite and troilite. The FeS2 pyrite phase was confirmed using various characterization techniques that included SEM, EDS, XRD and XPS.
In this work, we report synthesis of pyrite thin films using tert-butyl disulfide (TBDS) and hydrogen sulfide (H 2 S) in one-step atmospheric pressure sulfurization of iron oxide films at 400 °C on a soda-lime glass, molybdenum coated soda-lime glass and sodium free glass substrates. The iron pyrite thin films grown using TBDS did not require the presence of sodium to form the pyrite phase, whereas H 2 S grown pyrite thin films did. It was observed that the pyrite formation and thus the sulfur diffusion into the oxide film was slower in TBDS compared to H 2 S. The synthesized films were characterized for their surface morphology and phase identification using scanning electron microscopy, tunneling electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS) measurements. The S:Fe atomic ratio as well as their chemical bonding states were monitored to obtain
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