Scalable and green formation of graphitic nanolayers produces highly conductive pyrolyzed paper toward sensitive electrochemical sensors

Abstract

While the pyrolyzed paper (PP) is a green and abundant material that can provide functionalized electrodes with wide detection win-dows for a plethora of targets, it poses long-standing challenges against...

Tuning the Chemical and Electrochemical Properties of Paper-Based Carbon Electrodes by Pyrolysis of Polydopamine

“…For the control sample (PP), it is observed that approximately 50% of the carbon is in sp 2 hybridization (∼284.3 eV). This result is indicative of the formation of π bonds that give rise to the high conductivity of PP . In addition, the presence of carbon with sp 3 -type hybridization (∼285.0 eV) was verified, referring to defect-like carbon.…”

“…Thus, the changes observed in the morphology in Figure b for each treatment step barely affect the roughness of the electrodes. To study alterations in the carbonaceous structure, we monitored D, D2, D3, D4, and G bands in Raman spectra , for the thermally treated samples, shown in Figure b. The D band (∼1335 cm –1 ) is related to aromatic clusters with more than six (6) rings, while the D2 (∼1500 cm –1 ), D3 (∼1200 cm –1 ), and D4 (∼1620 cm –1 ) bands are attributed, respectively, to disordered graphene surface layers, functional groups, and small aromatic clusters and ethers.…”

“…We observe the logarithmic values of R s decay exponentially as T p increases. Higher T p increases the electrical conduction by boosting the carbon sp 2 /sp 3 ratio and/or the percolation between the nanosized sp 2 clusters in the paper matrix, with the delocalization of π electrons being ultimately favored. Here, no significant differences in R s have been found between nonmodified and PDA-functionalized PP (both pyrolyzed at 1000 °C).…”

“…The second alternative relies on the use of a tubular furnace in a controlled inert atmosphere that converts the entire cellulosic material into carbon. Such route allows the control of the temperature during the process and several sheets of cellulose can be pyrolyzed in a single run. − The resulting material is hydrophobic since most of the oxygen-rich chemical groups are lost after pyrolysis. Thus, to tune the surface properties of paper-based carbon electrodes, a further functionalization step is mandatory.…”

“…In this work, we reported for the first time the tuning of wettability, surface chemistry, coating thickness, and area of the electrodes by pyrolysis of PDA on PP. First, we obtained PP electrodes using a route described in the literature. ,− Next, PP electrodes were incubated in the presence of dopamine at pH 8.5 until complete evaporation of the solvent resulting in the formation of PDA film of approximately 3.0 μm. The presence of PDA was confirmed by spectroscopy analysis.…”