One‐Pot Route to Gold Nanoparticles Embedded in Electrospun Carbon Fibers as an Efficient Catalyst Material for Hybrid Alkaline Glucose Biofuel Cells

Abstract

Traditional strategies to develop Au metal nanoparticle catalysts for glucose oxidation comprise Au nanoparticles (NPs) supported on electrode surfaces. In this work, the fabrication of a new material capable of acting as an abiotic anode for the electrooxidation of glucose was developed. The material is composed of electrospun carbon fibers containing gold nanoparticles formed in situ from a polyacrylonitrile (PAN) solution with HAuCl4. This approach allows the pre‐reduction of the gold salt by PAN under mild conditions without the need for extra energy and leads to very stable carbon–gold bonding with well‐dispersed AuNPs, not previously reported. The gold‐modified carbon fibers (Au@CFs) were characterized by SEM, energy‐dispersive X‐ray spectroscopy, XRD, and electrochemical analysis. The Au@CF electrodes showed electrochemical activity toward glucose oxidation in alkaline media. Combined to a bilirubin oxidase modified biocathode (BOD@CFs), the resulting hybrid glucose biofuel cell showed open‐circuit voltage and power density values of 0.75 V and 65 μW cm−2, respectively, which remained intact after 3 weeks.

Halide-regulated growth of electrocatalytic metal nanoparticles directly onto a carbon paper electrode

“…6b shows that Au electrodes exhibits improved kinetics (the reaction starts at E # 0.3 V vs. RHE) with ca. 100 mV shi towards lower electrode potentials compared to their counterparts in literature, 20,24 which is a good indicator for future application as anode material. Importantly, the peak current density is at least 2-fold higher while the present Au weight is only 4 wt% compared to 30 wt% for electrospinning 24 and low loading of 0.4 mg metal cm À2 compared to 3 mg metal cm À2 for electrodeposition.…”

“…100 mV shi towards lower electrode potentials compared to their counterparts in literature, 20,24 which is a good indicator for future application as anode material. Importantly, the peak current density is at least 2-fold higher while the present Au weight is only 4 wt% compared to 30 wt% for electrospinning 24 and low loading of 0.4 mg metal cm À2 compared to 3 mg metal cm À2 for electrodeposition. 20 In other words, the present carbon paper based Au materials exhibit highly enhanced activity with very low Au amount that is 7-fold lower than the literature.…”

“…One of the solutions was the self-assembled 3D metallic nano-architectures, which have received tremendous interest in catalysis. [17][18][19][20] Hence, direct syntheses of NPs onto carbon papers or glassy carbon have been initiated from methods of electrodeposition, [19][20][21][22][23] electrospinning, [24][25][26] and wall-jet conguration. 27 However, these methods result in high loading of precious metals and loss of catalytic activity due to the packing of NPs inside the electrode bers.…”

Nanostructured Inorganic Materials at Work in Electrochemical Sensing and Biofuel Cells

“…Various strategies for enzymatic electrode elaboration have been developed by different groups leading to efficient performances in vitro [30,[175][176][177][178][179][180][181] (from 1 to over 1000 µW·cm -2 ) and in those implanted in living organisms [124,[182][183][184][185][186][187][188]. Aiming to provide larger specific surface areas and a higher density of surface active sites, different methods have been developed to substitute one of the electrodes, mostly the anode, with an abiotic one, leading to the concept of the hybrid biofuel cell (hBFC) [180,[189][190][191], and in some cases, all the electrodes are substituted by abiotic catalysts [174,181,[192][193][194][195][196].…”

Electrochemical Reactivity at Free and Supported Gold Nanocatalysts Surface

“…As the majority of the methods for synthesizing noble metal NPs involve surfactants, which are undesired for electrocatalysis application because of their adsorption on catalytic sites, elegant methods for the direct "printing" of AuNPs onto carbon papers or fibers to be used directly in electrocatalysis have been initiated. Figure 3A shows the SEM image of AuNPs embedded in electrospun carbon fibers (CFs) at the metal loading of 26 wt.% [42]. In typical experiment, HAuCl 4 is first mixed into preheated N,N-dimethylformamide (DMF) at 70°C, followed by the slow addition of polyacrylonitrile (PAN, M W = 150,000) and stirred for 3 h. The obtained electrospun felts are stabilized in air at 250°C for 2 h and then carbonized at 1000°C for 1 h under N 2 .…”