Synthesis and characterisation of VG nanosheets on silica aerogel by plasma‐enhanced chemical vapour deposition method

Abstract

Vertical graphene (VG) nanosheets are directly grown on silica aerogel and silicon substrate (100) by plasma-enhanced chemical vapour deposition process in the presence of hydrogen as a reducing agent at atmospheric pressure at 800°C. The physiochemical properties of the nanohybrid were thoroughly characterised by Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The presence of full wave half maximum of D, G and D′ indicates VG nanowalls. The height (≅50 nm) of the VG nanowalls were confirmed by SEM and Raman spectroscopy but AFM reveals it as ≅ 15 nm. Surface and cross-sectional SEM show the uniform distribution of vertical growth of nanowalls and the AFM revealed surface morphology of VG nanowalls.

Assembling Nano–Microarchitecture for Electromagnetic Absorbers and Smart Devices

“…Template is one key factor for template‐assisted CVD that tunes the specific surface area, pore structure distribution, morphology, and even macroscopic state. There are a variety of templates: i) metal porous templates that depend on carbon sources and temperature conditions; [ 36–38 ] ii) inorganic non‐metal templates (e.g., silica, zeolite, salt) that can fabricate 3D materials from sub‐nanometer to micrometer but needs assistance of high temperature owing to lack of catalytic ability; [ 39–41 ] iii) other templates, including metal oxides, etc. [ 42–45 ] In addition, template etching process also influences the properties of 3D architectures prepared by template‐assisted CVD, reported by Pettes et al [ 46 ]…”

“…Diverse assembly strategies bestow 3D architectures with customizability. For example, bottom–up growth method, especially CVD, facilitates the establishment of perfect 3D conductive network; [ 36–47,53–55 ] self‐assembly approach benefits the multi‐component integration for magnetic‐dielectric synergistic reinforce; [ 80 ] LBL construction works wonders in multilayer structure to control multiple interfacial effect; [ 95–102 ] molecular engineering is conducive to precise tailoring of crystal structures. [ 62,104,105 ] Furthermore, the adjustment of fabrication conditions, such as template, [ 38–45 ] flow rate, [ 36,37,47 ] reducing agent, [ 70–74 ] filler concentration, [ 58–68 ] and temperature, [ 81 ] that decide material density, pore size, and direction, as well as strength and toughness, etc., also regulates the EM response of 3D architectures to lay a solid foundation for designing smart EM devices.…”

“…At the same time, new technologies, new effects, new mechanisms, new materials, and new structures are bringing limitless vitalities to smart devices, and driving them towards integration, diversification, miniaturization, high performance, precision, and so on. [ 36–121 ] Nowadays, around 3D architectures and their smart devices, a new research hotspot in the interdisciplinary fields of physics, chemistry, materials, electronics, and other technical sciences is formed. Thousands of publications have been reported, with exponential growth.…”

Revealing Disparities in Porous Networks Between Yttria Aerogel Assemblies with Nanosheets and Nanoparticles and Their Ultrathermal Insulation and Optical Properties

“…12 These nanosheets exhibit tunable, size-dependent physical and chemical properties that are not achievable with isotropic nanoparticles. 13,14 The sol-gel process enables irregular packing of anisotropic nanosheet building blocks, leading to more complex porous networks; however, the exploration of these unique pore collections which are different from those formed by nanoparticle assemblies and the resultant distinct properties remains limited.…”

“…Generally, the skeleton consists of interconnected nanoparticles resembling a pearl-necklace architecture. , Recent advancements have introduced anisotropic structures, specifically 2D nanosheets, into aerogels, resulting in distinctive morphologies and exceptional mechanical, thermal, and optical properties . These nanosheets exhibit tunable, size-dependent physical and chemical properties that are not achievable with isotropic nanoparticles. , The sol-gel process enables irregular packing of anisotropic nanosheet building blocks, leading to more complex porous networks; however, the exploration of these unique pore collections which are different from those formed by nanoparticle assemblies and the resultant distinct properties remains limited.…”