Laser-Induced Graphene from Wood Impregnated with Metal Salts and Use in Electrocatalysis

Abstract

The hybridization of graphene with other inorganic nanostructures has endowed graphene with enhanced and varied functionalities. Here we demonstrate a facile and improved approach to convert biodegradable cedar wood into graphene embedded with various metal nanocrystals (cedar-LIG-M, LIG is laser-induced graphene, M = Cu, Co, Ni, Fe, NiFe) by sonication-assisted soaking and one-step CO2 laser scribing. Organic biomass was transformed to hierarchical porous graphene via laser induction, whereas metal salts were reduced to elemental metals simultaneously by the carbothermal reaction and reducing atmosphere generated during the lignocellulose decomposition. The as-prepared cedar-LIG-M possesses an ordered porous structure, good conductivity, unique ferromagnetic behavior and excellent electrochemical catalytic performance. As a demonstration, the cedar-LIG-NiFe electrode has a low overpotential of 296 mV at a current density of 10 mA cm–2 for oxygen evolution reactions. The performance of the electrode continued to improve at the initial testing stage due to the in situ activation as a result of the increased oxidation states of nickel and iron during electrochemical oxygen evolution. In addition, the cedar-LIG-NiFe could also serve as an electromagnetic interference shielding material with shielding effectiveness up to 54 dB. The simplicity and versatility of this technique provides a route for the synthesis of various carbon-based hybrid materials with potential applications of the products in many different fields, such as energy storage, electrocatalysis, electromagnetic interference shielding, and water treatment.

3D Carbon Materials for Efficient Oxygen and Hydrogen Electrocatalysis

“…The printing and patterning of 1D and 2D carbon structures on the conductive substrates, followed by coating their surface with thin layers of acid‐resistant conducting inks with suitable porogens, can also improve the porosity and the stability of the active layers in the resulting 3D structures . The surface treatment of such conductive layers with plasma or high energy CO 2 lasers could also form controlled oxidative defects (zig‐zag edges) and hierarchical pores (holes) with stable active sites, which could lead to better performance in OER …”

Laser-Induced Graphene: En Route to Smart Sensing

“…Since LIG's discovery, tremendous research efforts across the globe have been paid to improve the synthesis of LIG and transiting it into a plethora of application areas. For the synthesis, the precursors have been extended from PI to almost all kinds of substrates such as various commercial polymers [3,25], metal/plastic composites [26,27], and naturally occurring materials [12,28]. In addition, LIG can be easily embedded in other host materials to form functional composites [29,30], which improves the mechanical flexibility and stretchability.…”

Laser Irradiation of Electrode Materials for Energy Storage and Conversion

“…The successfully fabricated structures include but are not Figures 7B-7D. [89][90][91][92][93][94] In addition to these achievements, the highly controlled heating enabled by laser irradiation permits intriguing heterostructures ll that have rarely been realized by other methods. A scalable graphene membrane with different carbonization degrees along the vertical direction made by elaborately controlling the lasing process (wavelength: 1,064 nm; CW) contributes to a Janus super-hydrophobic/super-hydrophilic structure.…”

“…The past few years have witnessed the significantly boosted performance of electrocatalysts enabled by structural defects, heterostructures, and innovative electrode design, and all of the three structural features can be easily regulated by laser technologies. 16,23,90 To engineer structural defects in electrocatalysts, the chemical reduction of the assynthesized catalysts in a reduced atmosphere at elevated temperatures is generally required and the fabrication process is usually tedious and time consuming. By using LFL this obstacle can be essentially avoided, as the fragmented particles are rich in defects because of their unique formation process.…”

“…The loaded active species include Co 3 O 4 , NiFe LDH, Pt, and CoP, among others. 90,105,147 Because of the improved electron transfer, most of these structures afford significantly improved performance.…”