Lifang Deng

Nitrogen-doped carbon sheets derived from chitin as non-metal bifunctional electrocatalysts for oxygen reduction and evolution

Affordable, efficient electrocatalysts for oxygen reduction reactions (ORR) and oxygen evolution reactions (OER) are critical for various energy technologies. Herein, we report that an activated carbon sheet (ACS) derived from chitin is an efficient non-metal bifunctional electrocatalyst for both ORR and OER. In alkaline media, the as-prepared ACS exhibited remarkable electrocatalytic activity for the oxygen reduction reaction, which was significantly superior to an unactivated carbon sheet (CS) and comparable to the commercial Pt/C catalyst with excellent durability and resistance to the crossover effect. Meanwhile, the same ACS also presents high catalytic activity towards OER, with a small overpotential of ∼1.64 ± 0.02 V versus RHE. The excellent electrocatalytic properties of the ACS originated from the combined effect of optimal nitrogen doping, high surface area, and porous architecture. This work demonstrates that the ACS is a promising material candidate with high-performance in electrocatalytic applications in energy technologies.

Nonactivated and Activated Biochar Derived from Bananas as Alternative Cathode Catalyst in Microbial Fuel Cells

Nonactivated and activated biochars have been successfully prepared by bananas at different thermotreatment temperatures. The activated biochar generated at 900°C (Biochar-act900) exhibited improved oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performances in alkaline media, in terms of the onset potential and generated current density. Rotating disk electron result shows that the average of 2.65 electrons per oxygen molecule was transferred during ORR of Biochar-act900. The highest power density of 528.2 mW/m2 and the maximum stable voltage of 0.47 V were obtained by employing Biochar-act900 as cathode catalyst, which is comparable to the Pt/C cathode. Owning to these advantages, it is expected that the banana-derived biochar cathode can find application in microbial fuel cell systems.

Optimization of biodrying pretreatment of municipal solid waste and microbial fuel cell treatment of leachate

The biodrying pretreatment of municipal solid waste (MSW) and the treatment of leachate were investigated. The biological oxygen demand (BOD) and NH4+-N concentration of leachate from MSW biodrying pretreatment were measured, and the optimal conditions for MSW biodrying pretreatment and microbial fuel cell (MFC) performance were established. The results show that the optimal temperature and time for biodrying pretreatment of MSW were 40°C and 6 day, resulting in 30% weight loss of MSW, 20,800 mg/L leachate BOD, and 1,410 mg/L leachate NH4+-N. Effects of leachate properties on MFC performance were then studied. The optimal conditions for electricity generation of the MFC were neutral pH, 5,093 mg/L leachate BOD, and 341 mg/L leachate NH4+-N. The stable voltage of MFC generated using diluted leachate was 0.32 V, and the removal efficiencies of BOD and NH4+-N by the MFC were 86.0 and 88.8% after 7 day of treatment, respectively. These findings provide guidelines for the pretreatment of MSW and the treatment of leachate, and for further research and actual engineering application.

Improved performance of microbial fuel cells through addition of trehalose lipids

Electron transfer from microorganisms to the electrode is the key process in microbial fuel cells (MFCs). In this study, a trehalose lipid was added to a Rhodococcus pyridinivorans-inoculated MFC to improve the power output by enhancing electron transfer. Upon trehalose lipid addition, the current density and maximum power density were increased by 1.83 times and 5.93 times, respectively. Cyclic voltammetry analysis revealed that the addition of trehalose lipid increased the electron transfer performance, while electrochemical impedance spectroscopy results proved a decrease in internal resistance. Microscopy images showed that the trehalose lipid-treated bacteria interacted more closely with various fagellum-like contacts, while in the pure trehalose lipid (200 mg/L), pores were obviously observed in the cell surface. Importance Improving the power output of microbial fuel cells by the addition of bio-surfactants have been proved to be a novel method. However, only rhamnolipid and sophorolipid are certified to be effective. Trehalose lipid is a common material in cosmetic and bio-medicine industry. Our research broaden the application of bio-surfactant in MFC and preliminarily explain the mechanism. Highlights Trehalose lipid enhanced MFC power generation Trehalose lipid decrease MFC internal resistance Pores were observed with the addition of trehalose lipid Addition of bio-surfactant is a promising way to increase MFC performance

Steamed cake-derived 3D carbon foam with surface anchored carbon nanoparticles as freestanding anodes for high-performance microbial fuel cells

Anode design is highly significant for microbial fuel cells, since it simultaneously serves as the scaffold for electroactive microorganisms and as a medium for electron migration. In this study, a stiff 3D carbon foam with surface anchored nitrogen-containing carbon nanoparticles was facilely constructed via in-situ polyaniline coating of carbonized steamed cake prior to the carbonization process. The resultant product was determined to be an excellent freestanding anode that enabled the microbial fuel cell to deliver a maximum power density of up to 1307 mW/m2, which significantly outperformed its non-coated counterpart, the widely used commercial carbon felt. Further investigations revealed that the overall performance enhancement was associated with the open porosity, enlarged electroactive surface, increased biocompatibility, and decreased electric resistance of the anode scaffold. This promising anode material would offer a green and economical option for fabricating high-performance microbial fuel cell-based devices towards various ends.

Enhanced Rhodococcus pyridinivorans HR-1 anode performance by adding trehalose lipid in microbial fuel cell

In this study, a trehalose lipid was added to a Rhodococcus pyridinivorans-inoculated MFC to improve the power output by enhancing electron transfer. Upon trehalose lipid additions of different concentrate from 0 to 20 mg/L, the maximum power density increased from 54.7 mW/m2 to 324.4 mW/m2 (5.93 times) while the corresponding current density was 3.66 times increased from 0.35 A/m2 to 1.28 A/m2. Cyclic voltammetry analysis revealed that the addition of trehalose lipid increased the electron transfer performance, while electrochemical impedance spectroscopy results proved a decrease in internal resistance. It was demonstrated that adding bio-surfactant in MFC was a novel way to enhance power output performance.