Dr. Murilo Santhiago, Dr. Mathias Strauss, Mariane P. Pereira, Andréia S. Chagas, Dr. Carlos C.B. Bufon
*Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Zip Code 13083-970, Campinas, Sao Paulo, Brazil.
**Institute of Chemistry (IQ), UNICAMP, 13083-970, Campinas, Brazil.
***Institute of Physics “Gleb Wataghin” (IFGW), UNICAMP, 13083-859, Campinas, Brazil.
A simple and fast fabrication method to create high performance pencil-drawn electrochemical sensors is reported for the first time. The sluggish electron transfer observed on bare pencil-drawn surfaces was enhanced using two electrochemical steps: first oxidizing the surface and then reducing it in a subsequent step. The heterogeneous rate constant was found to be 5.1´10-3 cm s-1, which is the highest value reported so far for pencil-drawn surfaces. We have mapped the origin of such performance by atomic force microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. Our results suggest that the oxidation process leads to chemical and structural transformations on the electrode surface. As a proof-of-concept, we have modified the pencil-drawn surface with Meldola’s blue to electrocatalytic detect nicotinamide adenine dinucleotide (NADH). The electrochemical device exhibited the highest catalytic constant (1.7´105 L mol-1 s– 1) and the lowest detection potential for NADH reported so far in paper-based electrodes.
ACS Appl. Mater. Interfaces, (2017) 10.1021/acsami.6b15646
Direct link: http://pubs.acs.org/doi/abs/10.1021/acsami.6b15646