Porous 3D Graphene from Sustainable Materials: Laser Graphitization of Chitosan

Laser-fabrication of graphene from cellulose-based feedstock materials often requires extensive preprocessing. This work demonstrates laser fabrication of porous, 3D graphene from a new class of marine-based sustainable materials-chitosan biopolymers. The biopolymer films contain only chitosan, acetic acid, glycerol, and water. Fourier transform infrared spectroscopy studies indicate that the cured chitosan films still retain a significant water content (approximate to 30%), enabling production of flexible films. A simple 3-step laser fabrication process is presented using low-cost infrared (CO2, 2.1 W) and visible (405 nm, 0.5 W) hobbyist laser engravers, with measured sheet resistance values as low as 40 ohms sq.(-1). Transient electrochemical detection of an inner sphere redox molecule is demonstrated using a graphene-like carbon working electrode fabricated on a water-soluble chitosan substrate.