Advanced Energy Technologies
Mina Bahraminasab; Hamed Moqtaderi; Atiyeh Kiaeinejad
Abstract
Microbial Fuel Cells (MFCs) represent an environmentally-friendly approach to generating electricity, but the need to study variation parameters to find improvement conditions has been an important challenge for decades. In this study, a single-chamber MFC was designed to investigate the key parameters ...
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Microbial Fuel Cells (MFCs) represent an environmentally-friendly approach to generating electricity, but the need to study variation parameters to find improvement conditions has been an important challenge for decades. In this study, a single-chamber MFC was designed to investigate the key parameters such as the concentration and type of bacteria, chamber temperature, electrode spacing, and substrate rotation speed that affected the performance of MFCs. Therefore, two types of bacteria, Shewanella oneidensis (S.one) and Escherichia coli (E. coli), were compared as microorganisms. Then, the function of MFC was investigated under the following condition: three temperatures (30 ℃, 45℃, and 60℃), three bacterial concentrations (0.5% (v/v) (4.5 mg/ml), 1% (v/v) (9mg/ml), and 1.5% (v/v) (13.5mg/ml)), electrode distances (2 cm, 3 cm, 4cm), and substrate speeds (100 rpm, 150 rpm, 200 rpm). Ultimately, (S.one) bacteria, a chamber temperature of 45 ℃, a bacterial concentration of 1% (v/v) (9mg/ml), a cathode-anode spacing of 3 cm, and a rotation speed of 150 rpm proved to be the most efficient parameter settings for the constructed microbial fuel cell. The maximum voltage and highest power density were 486.9 mV and 9.73 mW/ , respectively, with a resistance of 7500 ohms. These results are meaningful for determining and improving important parameters in an MFC device.
Renewable Energy Resources and Technologies
Mohammad Reza Shekari; Seyed Mohammad Sadeghzadeh; Mahdi Golriz
Abstract
In recent decade, Perovskite Solar Cells (PSCs) have received considerable attention compared to other photovoltaic technologies. Despite the improvement of Power Conversion Efficiency (PCE) of PSCs, the chemical instability problem is still a matter of challenge. In this study, we have fabricated two ...
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In recent decade, Perovskite Solar Cells (PSCs) have received considerable attention compared to other photovoltaic technologies. Despite the improvement of Power Conversion Efficiency (PCE) of PSCs, the chemical instability problem is still a matter of challenge. In this study, we have fabricated two kinds of PSCs based on gold and carbon electrodes with the optimal PCE of about 15 % and 10.2 %, respectively. We prepared a novel carbon electrode using carbon black nanopowder and natural graphite flaky powder for Hole Transport Material (HTM) free carbon-based PSC (C-PSC). Current density-voltage characteristics over time were measured to compare the stability of devices. Scanning Electron Microscope (SEM) and Energy-dispersive X-ray Spectroscopy (EDS) analyses were carried out to study applied materials, layer, and surface structures of the cells. The crystal structure of perovskite and its association with the stability of PSCs were analyzed using an obtained X-ray diffraction (XRD) pattern. As a result, the constructed HTM-free C-PSC demonstrated high stability against air, retaining up to 90 % of its optimal efficiency after 2000 h in the dark under ambient conditions (relative humidity of (50 ± 5); average room temperature of 25 °C) in comparison to constructed gold-based PSCs (Gold-PSC) which are not stable at times. The experimental results show that novel low-cost and low-temperature carbon electrode could represent a wider prospect of reaching better stability for PSCs in the future.
