Pt-decorated nanoporous gold for glucose electrooxidation in neutral and alkaline solutions
© Yan et al; licensee Springer. 2011
Received: 1 February 2011
Accepted: 7 April 2011
Published: 7 April 2011
Exploiting electrocatalysts with high activity for glucose oxidation is of central importance for practical applications such as glucose fuel cell. Pt-decorated nanoporous gold (NPG-Pt), created by depositing a thin layer of Pt on NPG surface, was proposed as an active electrode for glucose electrooxidation in neutral and alkaline solutions. The structure and surface properties of NPG-Pt were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), and cyclic voltammetry (CV). The electrocatalytic activity toward glucose oxidation in neutral and alkaline solutions was evaluated, which was found to depend strongly on the surface structure of NPG-Pt. A direct glucose fuel cell (DGFC) was performed based on the novel membrane electrode materials. With a low precious metal load of less than 0.3 mg cm-2 Au and 60 μg cm-2 Pt in anode and commercial Pt/C in cathode, the performance of DGFC in alkaline is much better than that in neutral condition.
Glucose is widely used in modern life and industry as a nontoxic, inexpensive, and renewable resource. Since Rao and Drake  first reported the glucose oxidation on platinized-Pt electrodes in phosphate buffer solution in the 1960s, electrocatalytic oxidation of glucose has been extensively investigated as a key reaction in the fields of sensors [2, 3] and fuel cells [4, 5]. Great efforts have been made to develop catalytically active electrode materials for this reaction in the past two decades. As one of the most studied electrocatalyst, Pt was found to exhibit considerable activity for glucose oxidation at a negative potential in neutral and alkaline solutions . However, systematical study showed that this electrocatalytic process was subject to serious poisoning due to adsorbed intermediates from the oxidation of glucose . To mitigate the poisoning effect, Pt-based bimetallic catalysts such as Pt-Pb [8, 9], Pt-Ru [10, 11], and Pt-Au [4, 12], have been developed to improve the electrocatalytic activity and selectivity. On the other hand, it is increasingly realized that glucose electrooxidation is sensitive to surface structure of the electrocatalyst. For example, Adzic et al. found that this reaction strongly depended on the crystallographic orientation of the Pt electrode surface . Thus, significant attention has been focused on exploiting the potential applications of the nanostructured materials with special surface properties for glucose oxidation. Besides the widely used nanoparticles [14, 15], many other nanostructures were also studied, such as carbon nanotubes , ordered Pt nanotube arrays , mesoporous Pt electrodes , and nanoporous Pt-Pb and Pt-Ir networks [8, 19]. While these unique nanostructures exhibited considerable advantages as compared to traditional electrodes, they were mainly employed for glucose electrochemical detection. Exploiting nanostructures for potential applications in glucose fuel cell is still highly desirable.
Recently, Erlebacher and co-workers reported an interesting type of membrane electrode materials called nanoporous gold (NPG) leaves which could be made by chemically etching the white gold (AgAu alloy) leaves in corrosive medium . Coupled with surface functionalization with other catalytically active material, such as Pt, the 100-nm-thick high surface area electrode materials demonstrated superior activities toward a series of important electrochemical reaction including methanol oxidation [21, 22] and formic acid oxidation . Preliminary studies also proved they could work as promising electrocatalysts in proton exchange membrane fuel cells at ultra-low Pt loading [24, 25]. Here, we focus on their electrocatalytic properties toward glucose oxidation and its application in alkaline glucose fuel cells.
Reagents and apparatus
All chemicals were of analytical grade and used as purchased without further purification. D-Glucose, NaOH, HNO3 (65%), Na2HPO4·12H2O, NaH2PO4·2H2O, and H2PtCl6·6H2O were obtained from Sinopharm Chemical Reagent Co., Ltd. Au/Ag alloy (50:50, wt%) leaves with thickness of 100 nm (Sepp Leaf Products, New York) were used for NPG fabrication. Ultrapure water (18.2 MΩ) was used throughout the experiments and 0.1 M PBS was prepared with pH 7.4. The composition of NPG-Pt sample was determined by an IRIS Advantage inductively coupled plasma-atomic emission spectrometry (ICP-AES). The surface structure of NPG-Pt was observed JSM-6700F SEM and JEM-2100 TEM. The crystallographic information was obtained with XRD (Bruker D8 Advance X-ray diffractometer, Cu Kα radiation λ = 1.5418 Å) at a 0.02°/s scan rate. All electrochemical measurements were performed at room temperate in a traditional three-electrode electrochemical cell with a CHI 760C electrochemical workstation (Shanghai). Mercury sulfate electrode (MSE) was selected as reference electrode in all the electrochemical measurements, and a pure Pt foil as the counter electrode. Both PBS and the mixed solutions were purged with high pure nitrogen (99.999%) for 30 min prior to measuring.
Membrane electrode assembly (MEA) was prepared by attaching NPG-Pt to carbon paper (TGP-H-060, Toray, Japan) first, and then hot-pressed onto one side of a Nafion 115 membrane and commercial Pt/C (60 wt%, Johnson Matthey, UK) onto another side at 110°C and 1.5 MPa for 195 s. As-prepared MEAs were then assembled between high purity graphite plates as flow and current collecting plates, which have single channel serpentine flow pattern. The anolyte was pumped to anode by peristaltic pump, while pure oxygen was fed to the cathode without humidification by a massflow controller. The cell temperature was controlled through a temperature controller and monitored by thermocouples buried in the graphite blocks. The steady state polarization curves were recorded by automatic Electric Load (PLZ 70UA, Japan).
Preparation of NPG and NPG-Pt electrodes
NPG was made by dealloying commercial 12-carat white gold membrane in concentrated nitric acid for 20 min at 30°C . Subsequently, NPG were immediately transferred to ultrapure water and repeatedly washed to remove Ag+ and NO3 -. NPG-Pt samples were prepared by floating the as-prepared NPG membranes at the interface between the H2PtCl6 (1 g/L, pH = 10) solution and the vapor of hydrazine hydrate (85%) in a closed system . Deposition reaction occurred uniformly on the surface of NPG. The amount of Pt deposited onto the NPG substrate gradually accumulates with increasing plating time. The as-prepared NPG-Pt (loading of 0.1 mg cm-2 Au and 20 μg cm-2 Pt) samples were transferred into ultrapure water as soon as the plating reaction finished. Then NPG-Pt membranes were affixed onto the clean GC electrode (4 mm in diameter) and fixed with 2 μL dilute nafion solution (0.5 wt%). The as-prepared NPG-Pt electrode was dried at room temperature for 24 h before measurements.
Results and discussion
Surface and crystal structure of the NPG-Pt
Electrochemical characteristics of NPG-Pt in PBS
Electrocatalytic properties of NPG-Pt for glucose oxidation in neutral and alkaline solutions
DGFCs in neutral and alkaline solution
It also can be seen that the maximum power densities in alkaline (Figure 7b) was 4.4 mW cm-2 which is about 24 times than that in neutral solution (0.18 mW cm-2, Figure 7a). This should be mainly attributed to quicker reaction rate on the NPG-Pt in alkaline than that in neutral solution for glucose oxidation which was in line with the results of 3.3 above.
NPG-Pt membranes, a type of porous Au-Pt bimetallic nanostructures, were fabricated by chemically plating thin layer of Pt on NPG and were studied for glucose electrooxidation and the application in fuel cell. Taking advantage of the unique structure and high surface area, NPG-Pt exhibits considerable activity toward this reaction in neutral and alkaline solutions. In addition, glucose oxidation on NPG-Pt was found to be a surface sensitive process and Au-Pt surface alloy is highly active for oxidizing the adsorbed intermediate species resulted from the glucose electroadsorption. This means we could further improve the catalytic performance of NPG-Pt by tailoring the surface composite and structure. The results of DGFC test indicated that NPG-Pt is expected as a promising low precious metal loading electrocatalyst for application in glucose fuel cells.
direct glucose fuel cell
inductively coupled plasma-atomic emission spectrometry
membrane electrode assembly
mercury sulfate electrode
Pt-decorated nanoporous gold
scanning electron microscopy
transmission electron microscopy
X-ray powder diffraction.
This work was supported by the Ph.D. Programs Foundation of the MOE (20090131110019). We thank Prof. Y. Ding and HouYi Ma for valuable discussions and for sharing their nanomaterials and facilities.
- Rao MLB, Drake RF: Studies of electrooxidation of dextrose in neutral media. J Electrochem Soc 1969, 116: 334. 10.1149/1.2411841View Article
- Park S, Boo H, Chung TD: Electrochemical non-enzymatic glucose sensors. Anal Chim Acta 2006, 556: 46. 10.1016/j.aca.2005.05.080View Article
- Cosnier S, Szunerits S, Marks RS, Novoa A, Puech L, Perez E, Rico-Lattes I: A rapid and easy procedure of biosensor fabrication by micro-encapsulation of enzyme in hydrophilic synthetic latex films. Application to the amperometric determination of glucose. Electrochem Commun 2000, 2: 851. 10.1016/S1388-2481(00)00135-1View Article
- Habrioux A, Sibert E, Servat K, Vogel W, Kokoh KB, Alonso-Vante N: Activity of platinum-gold alloys for glucose electrooxidation in biofuel cells. J Phys Chem B 2007, 111: 10329. 10.1021/jp0720183View Article
- Spets JP, Kuosa MA, Kiros Y, Anttila T, Rantanen J, Lampinen MJ, Saari K: Enhancement of glucose electro-oxidation by an external electromagnetic field in direct-mode fuel cells. J Power Sources 2010, 195: 475. 10.1016/j.jpowsour.2009.06.110View Article
- Lei HW, Wu B, Cha CS, Kita H: Electro-oxidation of glucose on platinum in alkaline solution and selective oxidation in the presence of additives. J Electroanal Chem 1995, 382: 103. 10.1016/0022-0728(94)03673-QView Article
- Beden B, Largeaud F, Kokoh KB, Lamy C: Fourier transform infrared reflectance spectroscopic investigation of the electrocatalytic oxidation of D-glucose: identification of reactive intermediates and reaction products. Electrochim Acta 1996, 41: 701. 10.1016/0013-4686(95)00359-2View Article
- Wang J, Thomas DF, Chen A: Nonenzymatic electrochemical glucose sensor based on nanoporous PtPb networks. Anal Chem 2008, 80: 997. 10.1021/ac701790zView Article
- Cui HF, Ye JS, Liu X, Zhang WD, Sheu FS: Pt-Pb alloy nanoparticle/carbon nanotube nanocomposite: a strong electrocatalyst for glucose oxidation. Nanotechnology 2006, 17: 2334. 10.1088/0957-4484/17/9/043View Article
- Xiao F, Zhao F, Mei D, Mo Z, Zeng B: Nonenzymatic glucose sensor based on ultrasonic-electrodeposition of bimetallic PtM (M = Ru, Pd and Au) nanoparticles on carbon nanotubes-ionic liquid composite film. Biosens Bioelectron 2009, 24: 3481. 10.1016/j.bios.2009.04.045View Article
- Li LH, Zhang WD, Ye JS: Electrocatalytic Oxidation of Glucose at Carbon Nanotubes Supported PtRu Nanoparticles and Its Detection. Electroanalysis 2008, 20: 2212. 10.1002/elan.200804312View Article
- Jin C, Chen Z: Electrocatalytic oxidation of glucose on gold-platinum nanocomposite electrodes and platinum-modified gold electrodes. Synth Met 2007, 157: 592. 10.1016/j.synthmet.2007.06.010View Article
- Popovic KD, Markovic NM, Tripkovic AV, Adzic RR: Structural effects in electrocatalysis: Oxidation of D-glucose on single crystal platinum electrodes in alkaline solution. J Electroanal Chem 1991, 313: 181. 10.1016/0022-0728(91)85179-SView Article
- Tominaga M, Shimazoe T, Nagashima M, ITaniguchi M: Electrocatalytic oxidation of glucose at gold nanoparticle-modified carbon electrodes in alkaline and neutral solutions. Electrochem Commun 2005, 7: 189. 10.1016/j.elecom.2004.12.006View Article
- Aoun SB, Dursun Z, Koga T, Bang GS, Sotomura T, Taniguchi I: Effect of metal ad-layers on Au (111) electrodes on electrocatalytic oxidation of glucose in an alkaline solution. J Electroanal Chem 2004, 567: 175. 10.1016/j.jelechem.2003.12.022View Article
- Ye JS, Wen Y, Zhang WD, Gan LM, Xu GQ, Sheu FS: Nonenzymatic glucose detection using multi-walled carbon nanotube electrodes. Electrochem Commun 2004, 6: 66. 10.1016/j.elecom.2003.10.013View Article
- Yuan J, Wang K, Xia X: Highly ordered platinum-nanotubule arrays for amperometric glucose sensing. Adv Funct Mater 2005, 15: 803. 10.1002/adfm.200400321View Article
- Park S, Chung TD, Kim HC: Nonenzymatic glucose detection using Mesoporous platinum. Anal Chem 2003, 75: 3046. 10.1021/ac0263465View Article
- Hindle PH, Nigro S, Asmussen M, Chen AC: Amperometric glucose sensor based on platinum-iridium nanomaterials. Electrochem Commun 2008, 10: 1438. 10.1016/j.elecom.2008.07.042View Article
- Ding Y, Kim YJ, Erlebacher J: Nanoporous Gold Leaf: 'Ancient Technology'/Advanced Material. Adv Mater 2004, 16: 1897. 10.1002/adma.200400792View Article
- Zhang J, Liu P, Ma H, Ding Y: Nanostructured porous gold for methanol electro-oxidation. J Phys Chem C 2007, 111: 10382. 10.1021/jp072333pView Article
- Ge X, Wang R, Liu P, Ding Y: Platinum-decorated nanoporous gold leaf for methanol electrooxidation. Chem Mater 2007, 19: 5827. 10.1021/cm702335fView Article
- Ge X, Wang R, Cui S, Tian F, Xu L, Ding Y: Structure dependent electrooxidation of small organic molecules on Pt-decorated nanoporous gold membrane catalysts. Electrochem Commun 2008, 10: 1494. 10.1016/j.elecom.2008.07.045View Article
- Ding Y, Chen M, Erlebacher J: Metallic mesoporous nanocomposites for electrocatalysis. J Am Chem Soc 2004, 126: 6876. 10.1021/ja0320119View Article
- Zeis R, Mathur A, Fritz G, Lee J, Erlebacher J: Platinum-plated nanoporous gold: An efficient, low Pt loading electrocatalyst for PEM fuel cells. J Power Sources 2007, 165: 65. 10.1016/j.jpowsour.2006.12.007View Article
- Schofield EJ, Ingham B, Turnbull A, Toney MF, Ryan MP: Strain Development in Nanoporous Metallic Foils Formed by Dealloying. Appl Phys Lett 2008, 92: 043118. 10.1063/1.2838351View Article
- Hsiao MW, Adzic RR, Yeager EB: Electrochemical Oxidation of Glucose on Single Crystal and Polycrystalline Gold Surfaces in Phosphate Buffer. J Electrochem Soc 1996, 143: 759. 10.1149/1.1836536View Article
- Stetten F, Kerzenmacher S, Lorenz A, Chokkalingam V, Miyakawa N, Zengerle R, Ducree J: A one-compartment, direct glucose fuel cell for powering long-term medical implants. MEMS 2006, 934.
- Basu D, Basu S: A study on direct glucose and fructose alkaline fuel cell. Electrochimica Acta 2010, 55: 5775. 10.1016/j.electacta.2010.05.016View Article
- Jin C, Taniguchi I: Electrocatalytic activity of silver modified gold film for glucose oxidation and its potential application to fuel cells. Mater Lett 2007, 61: 2365. 10.1016/j.matlet.2006.09.013View Article
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.