Amine axial ligand-coordinated cobalt phthalocyanine-based catalyst for flow-type membraneless hydrogen peroxide fuel cell or enzymatic biofuel cell

In this study,an amine-coordinated cobalt phthalocyanine(CoPc)-based anodic catalyst was fabricated by a facile process,to enhance the performance of hydrogen peroxide fuel cells(HPFCs) and enzymatic biofuel cells(EBCs).For this purpose,polyethyleneimine(PEI) was added onto the reduced graphene oxide and CoPc composite(RGO/CoPc) to create abundant NH2 axial ligand groups,for anchoring the Co core within the CoPc.Owing to the PEI addition,the onset potential of the hydrogen peroxide oxidation reaction was shifted by 0.13 V in the negative direction(0.02 V) and the current density was improved by 1.92 times(1.297 mA cm^(-2)),compared to those for RGO/CoPc(0.15 V and 0.676 mA cm^(-2),respectively),due to the formation of donor-acceptor dyads and the prevention of CoPc from leaching out.The biocatalyst using glucose oxidase(GOx)([RGO/CoPc]/PEI/GOx) showed a better onset potential and catalytic activity(0.15 V and 318.7 μA cm^(-2)) than comparable structures,as well as significantly improved operational durability and long-term stability.This is also attributed to PEI,which created a favorable microenvironment for the enzyme.The maximum power densities(MPDs) and open-circuit voltages(OCVs) obtained for HPFCs and EBCs using the suggested catalyst were 105.2±1.3 μW cm^(-2)(0.317±0.003 V) and 25.4±0.9 μW cm^(-2)(0.283±0.007 V),respectively.This shows that the amine axial ligand effectively improves the performance of the actual driving HPFCs and EBCs.

A Glucose-Responsive Enzymatic Electrode on Carbon Nanodots for Glucose Biosensor and Glucose/Air Biofuel Cell

In this study, an enzymatic electrode for glucose biosensing and bioanode of glucose/air biofuel cell has been fabricated by immobilizing poly (methylene green) (polyMG) for electrocatalytic NADH oxidation and NAD+-dependent glucose dehydrogenase (GDH) for oxidizing glucose on carbon nanodots (CNDs). The polyMG-CNDscomposites obtained by electro-polymerization of dye MG molecules adsorbed on CNDs display excellent electrocatalytic activity toward NADH electro-oxidation at a low overpotential of ca. -0.10 V (vs. Ag/AgCl) and the integrated enzymatic electrode shows fast response to glucose electrooxidation. Using the fabricated GDH-based enzymatic electrode, a glucose biosensor was constructed and exhibits a wide linear dynamic range from 0 to 8 mM, a low detection limit of 0.02 μM (S/N = 3), and fast response time (ca. 4 s) under the optimized conditions. The developed glucose biosensor was used to detect glucose content in human blood with satisfactory results. The fabricated GDH-based enzymatic electrode was also employed as bioanode to assembly a glucose/air biofuel cell with the laccase-CNDs/GC as the biocathode. The maximum power density delivered by the assembled glucose/air biofuel cell reaches 3.1 μW·cm-2 at a cell voltage of 0.22 V in real sample fruit juice. The present study demonstrates that potential applications of GDH-based CNDs electrode in analytical and biomedical measurements.

Preparation of Close-Packed Silver Nanoparticles on Graphene to Improve the Enzyme Immobilization and Electron Transfer at Electrode in Glucose/O2 Biofuel Cell

In this study, chemical reduced graphene-silver nanoparticles hybrid （AgNPs@CR-GO） with close-packed AgNPs structure was used as a conductive matrix to adsorb enzyme and facilitate the electron transfer between im- mobilized enzyme and electrode. A facile route to prepare AgNPs@CR-GO was designed involving in β-cyclodextrin （β-CD） as reducing and stabilizing agent. The morphologies of AgNPs were regulated and controlled by various experimental factors. To fabricate the bioelectrode, AgNPs@CR-GO was modified on glassy carbon electrode followed by immobilization of glucose oxidase （GOx） or laccase. It was demonstrated by electrochemical testing that the electrode with close-packed AgNPs provided high GOx loading （Г=4.80 × 10^- l0 mol·cm^-2） and fast electron transfer rate （ks=5.76 s^-1）. By employing GOx based-electrode as anode and laccase based-electrode as cathode, the assembled enzymatic biofuel cell exhibited a maximum power density of 77.437 μW·cm^-2 and an open-circuit voltage of 0.705 V.

Uniform ordered mesoporous ZnCo2O4 nanospheres for super-sensitive enzyme-free H2O2 biosensing and glucose biofuel cell applications

Uniform, ordered mesoporous ZnCo2O4 （meso-ZnCo2O4） nanospheres were successfully synthesized using a sacrificing template method. The meso-ZnCo2O4 nanospheres were used for the first time for H2O2 biosensing and in glucose biofuel cells （GBFCs） as an enzyme mimic. The meso-ZnCo2O4 nanospheres not only exhibited excellent catalytic performance in the H2O2 sensor, achieving a high sensitivity （658.92 μA.mM-1.cm-2） and low detection limit （0.3 nM at signal-to-noise ratio （S/N） = 3）, but also performed as an excellent cathode material in GBFCs, resulting in an open circuit voltage of 0.83 V, maximum power density of 0.32 mW.cm-2, and limiting current density of 1.32 mA.cm-2. The preeminent catalytic abilities to H2O2 and glucose may be associated with the large specific surface area of the mesoporous structure in addition to the intrinsic catalytic activity of ZnCo2O4. These significant findings provide a successful basis for developing methods for the supersensitive detection of H2O2 and enriching catalytic materials for biofuel cells.

The direct use of enzymatic biofuel cells as functional bioelectronics

Enzymatic biofuel cells (EBFCs) are a subgroup of fuel cells that use enzymes as catalysts. EBFCs that utilizephysiological substrates such as glucose or lactate are of great interest as implantable or wearable power sourcesto activate medical devices. This contribution introduces the working principles of EBFCs and summarizes recentprogress in EBFC-enabled biosensors, pulse generators, and therapy. Biosensors with self-powered characteristicenjoy high selectivity, leading to potential “instrument-free” or “expensive-instrument-free” measurement.Autonomous pulse generation is based on the hybrid of EBFC and supercapacitor, which is promising for theapplication in medical related electrostimulation. By providing the direct electrical stimulation, or controllablyreleasing drug, EBFCs can also be used for self-powered therapeutic system. The further combination of self-powered sensing and treating enables EBFC as a possible platform of diagnostics and therapeutics. Future efforts can be focused on resolving the limited power density and lifetime of EBFC.

Live microalgal cells modified by L-cys/Au@carbon dots/bilirubin oxidase layers for enhanced oxygen reduction in a membrane-less biofuel cell

Electrochemical oxygen reduced reaction(ORR)is a critical element in clean energy development.Despite efforts to enhance gas transfer to the reaction interface,the low solubility of O_(2)molecules and slow diffusion rate in liquid electrolyte is still a significant challenge.Herein,we design an artificial outer membrane on microalgal cells,which consists of a carbon dots/bilirubin oxidase(CDs/BOD)ORR catalyst layer and a L-cystine/Au nanoporous O_(2)supply layer.O_(2)generated by photosynthesis from microalgal cells then can be directly transported to the CDs/BOD catalytic interfaces,overcoming the sluggish gas transfer in the electrolyte.Thus,the cathode constructed by the fabricated microalgal cells realizes an ORR current density of 655.2μA/cm^(2) with fast ORR kinetics,which is 2.68 times higher than that of a BOD cathode fed with pure O_(2).A membrane-less glucose/O_(2)biofuel cell is further developed using the hybrid artificial cells as the cathode,and the power density is 2.39 times higher than that of a BOD cathode biofuel cell in O_(2)saturated solution.This biomimetic design supplies O_(2)directly to the carbon dots/BOD catalyst layer from the microalgae membrane through a nanoporous L-cys/Au layer,providing an alternative solution for the transfer barrier of O_(2)in the electrolyte.

Effect of the protection layer formed by cross-linked gelatin on the stability and performance of glucose and oxygen fuel cells

A glucose oxidation catalyst comprising carbon nanotube,tetrathiafulvalene(TTF),gelatin,glutaraldehyde(GA)and glucose oxidase(GOx)(CNT/[TTF-GOx]/Gelatin+GA)is suggested to enhance the reactivity of glucose oxidation reaction(GOR),and the performance and stability of enzymatic biofuel cells(EBCs)using this catalyst.In this catalyst,TTF is used as mediator to transfer electron effectively,while GA is crosslinked to gelatin to form non-soluble network.The structure prevents the dissolution of gelatin from aqueous electrolyte and reduces the leaching-out of GOx and TTF molecules.To confirm the crosslinking effect of GA and gelatin,Fourier-transform infrared spectroscopy(FT-IR)and electrochemical evaluations are utilized.According to FT-IR analysis,it was observed that the amide I peak shifted after crosslinking.This is evidence showing the appropriate network formation and the reactivity of CNT/[TTFGOx]/Gelatin+GA is well preserved even after multiple potential cycling.In addition,its GOx activity is regularly monitored for one month and the measurements prove that the structure prevents the leaching out of GOx molecules.Based on that,EBC using the anodic catalyst shows excellent performances,such as open circuit voltage of 0.75 V and maximum power density of 184μW/cm^(2).

Transgenic woody plants for biofuel

Transgenic trees as a new source for biofuel have brought a great interest in tree biotechnology. Genetically modifying forest trees for ethanol production have advantages in technical challenges, costs, environmental concerns, and financial problems over some of crops. Genetic engineering of forest trees can be used to reduce the level of lignin, to produce the fast-growing trees, to develop trees with higher cellulose, and to allow the trees to be grown more widely. Trees can establish themselves in the field with less care of farmers, compared to most of crops. Transgenic crops as a new source for biofuel have been recently reviewed in several reviews. Here, we overview transgenic woody plants as a new source for biofuel including genetically modified woody plants and environment; main focus of woody plants genetic modifications; solar to chemical energy transfer; cellulose biosynthesis; lignin biosynthesis; and cellulosic ethanol as biofuel.

Current-Voltage Modeling of the Enzymatic Glucose Fuel Cells

Enzymatic fuel cells produce electrical power by oxidation of renewable energy sources. An enzymatic glucose biofuel cell uses glucose as fuel and enzymes as biocatalyst, to convert biochemical energy into electrical energy. The applications which need low electrical voltages and low currents have much of the interest in developing enzymatic fuel cells. An analytical modelling of an enzymatic fuel cell should be used, while developing fuel cell, to estimate its various parameters, to attain the highest power value. In this paper an analytical model for enzymatic glucose membraneless fuel cell with direct electron transfer was developed. The adequacy of the model was estimated by comparison with fuel cells parameters. The electrical characteristics of fuel cells are interpreted using this model, based on theoretical consideration of ions transportation in solution. The influence of the hydrogen ions, glucose and enzyme concentration and also a thickness of enzyme layer on electrical parameters of a fuel cell were investigated. The electrical parameters such as a current, a voltage, a power were calculated by the model, for various parameters of the fuel cells. The model aimed to predict a hydrogen ions current, an electrical voltage and an electrical power in enzymatic fuel cell with direct electron transfer. The model reveals that increasing the rates of hydrogen ions generation and consumption leads to higher value of current, voltage and power.

Physical Modeling of the Enzymatic Glucose-Fuelled Fuel Cells

An enzymatic glucose biofuel cell uses glucose as fuel and enzymes as biocatalyst, to transform biochemical energy into electrical energy. An analytical modelling of an enzymatic biofuel cell should be used, while developing fuel cell, to estimate its various enzymatic parameters, to obtain the highest voltage feasibly. The analytical model was developed, and the open circuit voltage (OCV) calculated by the model for various parameters of the fuel cell is in agreement with the experimental results. The OCV is interpreted by using this model, based on theoretical consideration of ions transportation in the solution. The generation and consumptions of the ions near the electrodes were defined in the model by exponential approximations, with different depletion coefficients. The model reveals that increasing the rates of hydrogen ions generation and (or) consumption by enzyme or chemical reactions leads to a higher value of OCV. The model points that the OCV is saturated with a glucose concentration and increased logarithmically with a surface enzyme concentration. Hence, a low glucose concentration is sufficient to obtain adequate OCV, on the one hand, but it can be increased by increasing electrode surface porosity, on the other hand. This model can be expanded to include time and close circuit voltage.

Screen-Printable Functional Nanomaterials for Flexible and Wearable Single-Enzyme-Based Energy-Harvesting and Self-Powered Biosensing Devices

Developing flexible bioelectronics is essential to the realization of artificial intelligence devices and biomedical applications, such as wearables, but their potential is limited by sustainable energy supply. An enzymatic biofuel cell(BFC) is promising for power supply, but its use is limited by the challenges of incorporating multiple enzymes and rigid platforms. This paper shows the first example of screen-printable nanocomposite inks engineered for a single-enzyme-based energy-harvesting device and a self-powered biosensor driven by glucose on bioanode and biocathode. The anode ink is modified with naphthoquinone and multiwalled carbon nanotubes(MWCNTs), whereas the cathode ink is modified with Prussian blue/MWCNT hybrid before immobilizing with glucose oxidase. The flexible bioanode and the biocathode consume glucose. This BFC yields an open circuit voltage of 0.45 V and a maximum power density of 266 μW cm-2. The wearable device coupled with a wireless portable system can convert chemical energy into electric energy and detect glucose in artificial sweat. The self-powered sensor can detect glucose concentrations up to 10 mM. Common interfering substances,including lactate, uric acid, ascorbic acid, and creatinine, have no effect on this self-powered biosensor. Additionally, the device can endure multiple mechanical deformations. New advances in ink development and flexible platforms enable a wide range of applications, including on-body electronics, self-sustainable applications, and smart fabrics.

Hydrogenase as the basis for green hydrogen production and utilization

Hydrogenase is a paradigm of highly efficient biocatalyst for H_(2) production and utilization evolved in nature. A dilemma is that despite the high activity and efficiency expected for hydrogenases as promising catalysts for the hydrogen economy, the poor oxygen tolerance and low yield of hydrogenases largely hinder their practical application. In these years, the enigmas surrounding hydrogenases regarding their structures, oxygen tolerance, mechanisms for catalysis, redox intermediates, and proton-coupled electron transfer schemes have been gradually elucidated;the schemes, which can well couple hydrogenases with other highly efficient(in)organic and biological catalysts to build novel reactors and drive valuable reactions, make it possible for hydrogenases to find their niches. To see how scientists put efforts to tackle this issue and design novel reactors in the fields where hydrogenases play crucial roles, in this review,recent advances were summarized, including different strategies for protecting enzyme molecules from oxygen, enzyme-based assembling systems for H_(2) evolution in the photoelectronic catalysis, enzymatic biofuel cells for H_(2) utilization and storage and the efficient electricity-hydrogen-carbohydrate cycle for high-purity hydrogen and biofuel automobiles. Limitations and future perspectives of hydrogenasebased applications in H_(2) production and utilization with great impact are discussed. In addition, this review also provides a new perspective on the use of biohydrogen in healthcare beyond energy.

生物燃料高效生产微生物细胞工厂构建研究进展

生物燃料替代化石燃料可解决当前全球正面临的能源危机和环境危机。通过筛选、改造微生物,利用可再生资源高效生产具有经济效益和社会效益的生物燃料已成为可持续生物制造的重大发展方向。基于系统生物学理解并设计细胞工厂生物燃料的合成途径与调控网络,利用合成生物学手段开发高产稳产微生物细胞工厂是实现生物燃料经济生产的重要手段。本文概述了当前生物燃料的主要种类及对应的代谢途径,并总结了当前主要生物燃料的生产情况。重点介绍从微生物物质代谢、能量代谢、生理代谢和信息代谢四个方面去认识、改造、开发微生物底盘细胞使其成为高产稳产的生物能源细胞工厂。此外,本文也对当前生物能源的生产瓶颈和挑战进行了总结,并从酶元件库的挖掘、合成途径的创建与优化、底盘细胞的理解和性能改善、发酵工艺的智能控制等方面提出了未来的发展方向和目标任务,强调了在未来的研究中,信息技术(IT)和生物技术(BT)交叉融合是能源细胞工厂构建的发展趋势,可为高效生物燃料细胞工厂的构建提供工具和资源,加速生物能源的产业化进程。

酶生物燃料电池

综述了酶生物燃料电池的研究进展,特别是近年来在电池结构、性能以及电池的正极和负极研究等方面的成果。详细介绍了酶燃料电池中酶电极的制备方法和用于酶电极修饰材料的研究现状,对酶燃料电池研究中需要解决的问题和发展方向进行了探讨。

生物燃料电池研究进展

生物燃料电池利用生物催化剂直接把化学能转化为电能,具有燃料来源广泛、反应条件温和、生物相容性好等优点。按采用催化剂的不同,可分为微生物燃料电池和酶生物燃料电池。简述了生物燃料电池的工作原理,综述了其最新的研究进展。微生物燃料电池发展的新方向主要是无介体微生物燃料电池的研究和高活性微生物的选用;而酶生物燃料电池的研究,集中在寻找固定酶的新方法,发展体积更小的无介体酶生物燃料电池,以及与太阳电池相结合等方面。对生物燃料电池未来的发展方向进行了展望。

生物燃料电池

简介了生物燃料电池的概念和工作原理 ,回顾了生物燃料电池的发展历史。对 80年代后两种生物燃料电池———微生物燃料电池和酶燃料电池的研究动态分别进行了总结 ,并对目前存在的主要问题进行了分析。阐述了当前研究的发展方向 ,预计随着燃料电池研究热潮的再度兴起和生物技术的高速发展 。

葡萄糖氧化酶在炭黑上的固定及直接电化学

经红外光谱和电化学测量证明,用简单的吸附法能将葡萄糖氧化酶(GOx)固定在炭黑(CB)表面.电化学测量表明,固定在CB上的GOx能进行准可逆的直接电化学反应,其式量电位(E0′)为-0.436V,在40-150mV·s-1范围内,不随扫描速率而变化.电化学反应速率常数(ks)为0.800s-1,比文献报道的大30多倍.而且,固定在CB上的GOx能保持其对葡萄糖氧化的生物电催化活性.即使在保存两周后,其电催化活性仅下降了5%,表明固定在CB上的GOx有良好的稳定性.

生物燃料电池的研究进展

简要介绍生物燃料电池的工作原理、分类,归纳近年来国内外研究现状.讨论了电子传递媒介体在生物燃料电池中的作用以及如何提高电池性能的对策.最后,探讨了影响生物燃料电池研究进展的瓶颈,并展望其应用前景.