TY  - JOUR
A1  - Werchmeister, Rebecka Maria Larsen
A1  - Tang, Jing
A1  - Xiao, Xinxin
A1  - Wollenberger, Ulla
A1  - Hjuler, Hans Aage
A1  - Ulstrup, Jens
A1  - Zhang, Jingdong
T1  - Three-Dimensional Bioelectrodes Utilizing Graphene Based Bioink
JF  - Journal of The Electrochemical Society
N2  - Enzyme immobilization using nanomaterials offers new approaches to enhanced bioelectrochemical performance and is essential for the preparation of bioelectrodes with high reproducibility and low cost. In this report, we describe the development of new three-dimensional (3D) bioelectrodes by immobilizing a "bioink" of glucose oxidase (GOD) in a matrix of reduced graphene oxides (RGOs), polyethylenimine (PEI), and ferrocene carboxylic acid (FcCOOH) on carbon paper (CP). CP with 3D interwoven carbon fibers serves as a solid porous and electronically conducting skeleton, providing large surface areas and space for loading the bioink and diffusion of substrate molecules, respectively. RGO enhances contact between the GOD-matrix and CP, maintaining high conductivity. The composition of the bioink has been systematically optimized. The GOD bioelectrodes show linearly increasing electrocatalytic oxidation current toward glucose concentration up to 48 mM. A hybrid enzymatic biofuel cell equipped with the GOD bioelectrode as a bioanode and a platinum cathode furthermore registers a maximum power density of 5.1 mu W cm(-2) and an open circuit voltage of 0.40 V at 25 degrees C. The new method reported of preparing a bioelectrode by drop-casting the bioink onto the substrate electrode is facile and versatile, with the potential of application also for other enzymatic bioelectrodes.
Y1  - 2019
U6  - https://doi.org/10.1149/2.0261916jes
SN  - 0013-4651
SN  - 1945-7111
VL  - 166
IS  - 16
SP  - G170
EP  - G177
PB  - The Electrochemical Society
CY  - Pennington
ER  - 
TY  - JOUR
A1  - Tang, Jing
A1  - Werchmeister, Rebecka Maria Larsen
A1  - Preda, Loredana
A1  - Huang, Wei
A1  - Zheng, Zhiyong
A1  - Leimkühler, Silke
A1  - Wollenberger, Ulla
A1  - Xiao, Xinxin
A1  - Engelbrekt, Christian
A1  - Ulstrup, Jens
A1  - Zhang, Jingdong
T1  - Three-dimensional sulfite oxidase bioanodes based on graphene functionalized carbon paper for sulfite/O-2 biofuel cells
JF  - ACS catalysis
N2  - We have developed a three-dimensional (3D) graphene electrode suitable for the immobilization of human sulfite oxidase (hSO), which catalyzes the electrochemical oxidation of sulfite via direct electron transfer (DET). The electrode is fabricated by drop-casting graphene-polyethylenimine (G-P) composites on carbon papers (CPs) precoated with graphene oxide (GO). The negatively charged hSO can be adsorbed electrostatically on the positively charged matrix (G-P) on CP electrodes coated with GO (CPG), with a proper orientation for accelerated DET. Notably, further electrochemical reduction of G-P on CPG electrodes leads to a 9-fold increase of the saturation catalytic current density (j(m)) for sulfite oxidation reaching 24.4 +/- 0.3 mu A to cm(-2), the highest value among reported DET-based hSO bioelectrodes. The increased electron transfer rate plays a dominating role in the enhancement of direct enzymatic current because of the improved electric contact of hSO with the electrode, The optimized hSO bioelectrode shows a significant catalytic rate (k(cat): 25.6 +/- 0.3 s(-1)) and efficiency (k(cat)/K-m: 0.231 +/- 0.003 s(-1) mu M-1) compared to the reported hSO bioelectrodes. The assembly of the hSO bioanode and a commercial platinum biocathode allows the construction of sulfite/O-2 enzymatic biofuel cells (EBFCs) with flowing fuels. The optimized EBFC displays an open-circuit voltage (OCV) of 0.64 +/- 0.01 V and a maximum power density of 61 +/- 6 mu W cm(-2) (122 +/- 12 mW m(-3)) at 30 degrees C, which exceeds the best reported value by more than 6 times.
KW  - enzymatic biofuel cell
KW  - reduced graphene oxide
KW  - sulfite oxidase
KW  - carbon paper
KW  - direct electron transfer
Y1  - 2019
U6  - https://doi.org/10.1021/acscatal.9b01715
SN  - 2155-5435
VL  - 9
IS  - 7
SP  - 6543
EP  - 6554
PB  - American Chemical Society
CY  - Washington
ER  -