Silicon Radical-Induced CH₄ Dissociation for Uniform Graphene Coating on Silica Surface

Due to the manufacturability of highly well-defined structures and wide-range versatility in its microstructure, SiO₂ is an attractive template for synthesizing graphene frameworks with the desired pore structure. However, its intrinsic inertness constrains the graphene formation via methane chemical vapor deposition. This work overcomes this challenge by successfully achieving uniform graphene coating on a trimethylsilyl-modified SiO₂ (denote TMS-MPS). Remarkably, the onset temperature for graphene growth dropped to 720 °C for the TMS-MPS, as compared to the 885 °C of the pristine SiO₂. This is found to be mainly from the Si radicals formed from the decomposition of the surface TMS groups. Both experimental and computational results suggest a strong catalytic effect of the Si radicals on the CH₄ dissociation. The surface engineering of SiO₂ templates facilitates the synthesis of high-quality graphene sheets. As a result, the graphene-coated SiO₂ composite exhibits a high electrical conductivity of 0.25 S cm^-1. Moreover, the removal of the TMP-MPS template has released a graphene framework that replicates the parental TMS-MPS template on both micro- and nano- scales. This study provides tremendous insights into graphene growth chemistries as well as establishes a promising methodology for synthesizing graphene-based materials with pre-designed microstructures and porosity.