Enhanced photo-electrochemical response of screen-printed electrodes based on g-C3N4 hollow spheres and other morphologies for sensing applications

• Published in: FlatChem 2022-09, Vol.35, p.100412, Article 100412
• Main Authors: Puentes-Prado, Elena, Gutiérrez-Granados, Silvia, Gómez-Solís, Christian, Ramírez-García, Gonzalo
• Format: Article
• Language: English
• Subjects: Graphitic carbon nitride; Hollow spheres; Nanosensors; Optoelectronics; Photo-electrochemistry
• ISSN: 2452-2627; 2452-2627
• DOI: 10.1016/j.flatc.2022.100412

[Display omitted] •Electrodes based on hollow spheres, fibers, sheets and bulk g-C3N4 materials were developed.•Those materials were applied for the non-enzymatic photo-electrochemical sensing of H2O2.•Hollow spheres triggered current signals up to 1000-fold more intense than other morphologies.•Current responses resulted up to 20-fold more intense under UV-light irradiation.•Hollow spheres are superior photo-electrochemical transducers for sensing applications. In this work, graphite-like carbon nitride (g-C3N4) materials were synthesized with different morphologies including bulk, fibers, sheets and hollow spheres, and their photo-electrocatalytic behaviors compared face-to-face. Thereafter, g-C3N4 materials were deposited on ITO substrates for the development of four photo-electrochemical sensing platforms. A systematic characterization evidenced the shape, surface area, crystal structure, composition, electronic structure, photophysical behavior and electrocatalytic activity contributions on an integral photo-electrochemical response. The voltammetric and amperometric results revealed a higher photo-electrocatalytic activity of the electrodes containing hollow spheres compared to other morphologies, with signals up to three orders of magnitude more intense when H2O2 was used as a molecule probe. Those electrodes also showed current responses up to 20-fold more intense under UV-light irradiation compared to measurements in darkness. The response intensification was attributed to a synergic contribution of i) superior adsorption and diffusion processes on the inner and outer faces of hollow spheres, ii) narrowed bandgap that allows extended absorption to the visible-light range with dramatically enhanced light-harvesting capability, iii) decreased recombination of the photogenerated electron-hole pairs, and iv) the presence of more abundant cyano (CN) functional groups which promotes interactions with small target analytes and catalyze some redox reactions. Thereby, morphology modulation resulted in a crucial strategy for improving the photo-electrochemical response of electrodes containing layered g-C3N4 materials. These results support the development of innovative substrates as signal-transducers for improved sensing applications.