You Yu

Recoverable hybrid enzymatic biofuel cell with molecular oxygen-independence.

Enzymatic biofuel cells (EBFCs) have drawn great attentions because of its potential in energy conversion. However, designing of highly efficient EBFCs which can adapt to the anaerobic system is still a great challenge. In this study, we propose a novel hybrid enzymatic biofuel cell (HEBFC) which was fabricated by a glucose dehydrogenase modified bioanode and a solid-state silver oxide/silver (Ag2O/Ag) cathode. The as-assembled HEBFC exhibited an open circuit potential of 0.59V and a maximum power output of 0.281mWcm(-2) at 0.34V in air saturated buffer. Especially, due to the introduction of Ag2O/Ag, our HEBFC could also operate under anaerobic condition, while the maximum power output would reach to 0.275mWcm(-2) at 0.34V. Furthermore, our HEBFC had stable cycle operation and could keep high power output for a certain time as the result of the regeneration of Ag2O. Our work provides a new concept to develop EBFCs for efficient energy conversion in the future.

RGO/Au NPs/N-doped CNTs supported on nickel foam as an anode for enzymatic biofuel cells

In this study, three-dimensional reduced graphene oxide/Au NPs/nitrogen-doped carbon nanotubes (RGO/Au NPs/N-doped CNTs) assembly supported on nickel foam was utilized as an anode for enzymatic biofuel cells (EBFCs). 3D RGO/Au NPs was obtained by electrodepositing reduced graphene oxide on nickel foam (Ni foam), while Au NPs were co-deposited during the process. Afterwards, nitrogen doped CNTs (N-CNTs) were allowed to grow seamlessly on the surfaces of 3D RGO/Au NPs via a simple chemical vapor deposition (CVD) process. In this nanostructure, Au NPs co-deposition and nitrogen doping offer more active sites for bioelectrocatalysis. Additionally, N-CNTs were demonstrated providing high specific surface area for enzyme immobilization and facilitating the electron transfer between glucose oxidase (GOx) and electrode. The resulting bioanode achieved efficient glucose oxidation with high current densities of 7.02mAcm-2 (0.3V vs. Ag/AgCl). Coupling with a Pt cathode, the fabricated glucose/air biofuel cell exhibited an open-circuit potential of 0.32V and generated a maximum power density 235µWcm-2 at 0.15V. This novel electrode substrate achieved high performance in current density at bioelectrochemical systems and could be useful for further exploiting the application of three dimensional carbon-based nanomaterials in EBFCs.

A miniature origami biofuel cell based on a consumed cathode

Considerable interest has been focused on miniature biofuel cells (BFCs) because of their portability and possibility to be implantable. Origami devices with hollow channels will provide novel insight into the assembly methods of miniature BFCs. Herein a miniature origami BFC has been fabricated from a MnO2-graphite flake consumed solid-state cathode. For further practical applications, miniature origami BFCs can directly generate energy from soft drinks.

Fuel‐Free Bio‐photoelectrochemical Cells Based on a Water/Oxygen Circulation System with a Ni:FeOOH/BiVO4 Photoanode

A bio-photoelectrochemical cell (BPEC) based on a fuel-free self-circulation water-oxygen-water system was fabricated. It consists of Ni:FeOOH modified n-type bismuth vanadate (BiVO4 ) photoanode and laccase catalyzed biocathode. In this BPEC, irradiation of the photoanode generates photocurrent for photo-oxidation of water to oxygen, which is reduced to water again at the laccase biocathode. Of note, the by-products of two electrode reactions could continue to be reacted, which means the H2 O and O2 molecules are retained in an infinite loop of water-oxygen-water without any sacrificial chemical components. As a result, the assembled fuel-free BPEC exhibits good performance with an open-circuit potential of 0.97 V and a maximum power density of 205 μW cm-2 at 0.44 V. This BPEC based on a self-circulation system offers a fuel-free model to enhance multiple energy conversion and application in reality.

Facile synthesis of Ni based metal-organic frameworks wrapped MnO 2 nanowires with high performance toward electrochemical oxygen evolution reaction

The transition metal oxides based catalysts have drawn great attention for their application in the electrolysis of water for renewable energy generation. Although manganese oxides were rarely used as oxygen evolution reaction (OER) catalysts, they were still considered as active and efficient OER catalysts due to the earth-abundant and low toxic nature of manganese. In this work, we proposed a facile method for the synthesis of high-performance electrochemical OER catalyst by magnetically stirring the mixture of 1,3,4-thiadiazole-2,5-dithiol (DMTD), Ni2+ and MnO2 nanowires (NWs) in ethanol at room temperature, noted as Ni/DMTD/MnO2. The Ni/DMTD complex and MnO2 NWs showed synergistically enhanced OER activity and excellent durability in alkaline solution. The introducing of MnO2 and the presence of Ni3+ after the oxidation of Ni2+ were the key factors which improve the OER performance. The potential at 10 mA cm-2 was 1.492 V (vs RHE) with a Tafel slope of 69.46 mV dec-1 in 1 M KOH aqueous solution, comparable to the state-of-art RuO2. The results indicated that MnO2 was found to have the capability to enhance not only the catalytic activity but also operation stability of Ni/DMTD/MnO2 towards OER.

Point-of-Care Diagnoses: Flexible Patterning Technique for Self-Powered Wearable Sensors

This paper demonstrated the fabrication of a facile, low-cost, and self-powered platform for point-of-care fitness level and athletic performance monitoring sensor using electrochemical lithography method and its application in body fluid sensing. Flexible Au/prussian blue electrode was employed as the indicating electrode, where the color change was an indication of fitness level and athletic performance. A piece of Al foil, Au/multiwalled carbon nanotubes (MWCNTs)-glucose dehydrogenase, and Au/polymethylene blue-MWCNTs-lactic dehydrogenase electrodes were used for the detection of ionic strength, glucose, and lactic acid in sweat, respectively, which allows the sensor to work without any extra instrumentation and the output signal can be recognized by the naked eyes. The advantages of these sensors are (1) self-powered; (2) readily applicable to the detection of any electroactive substance by an electrochromic material; (3) easy to fabricate via two steps of EDP; and (4) point-of-care. By assembling the energy and sensing components together through a transparent adhesive tape, the proposed self-powered wearable biosensor exhibits superior performances, indicating its broad applied prospect in the point-of-care diagnoses.