Controlled Synthesis of Carbon Nanospheres via the Modulation of the Hydrophilic Length of the Assembled Surfactant Micelles

A review of the recent trend in the synthesis of carbon nanomaterials derived from oil palm by-product materials

Grown only in humid tropical conditions, the palm tree provides high-quality oil essential for cooking and personal care or biofuel in the energy sector. After the refining process, this demand could cause numerous oil palm biomass waste management problems. However, the emergence of carbon nanomaterials or CNMs could be a great way to put this waste to a good cause. The composition of the palm waste can be used as a green precursor or starting materials for synthesizing CNMs. Hence, this review paper summarizes the recent progress for the CNMs production for the past 10 years. This review paper extensively discusses the method for processing CNMs, chemical vapor deposition, pyrolysis, and microwave by the current synthesis method. The parameters and conditions of the synthesis are also analyzed. The application of the CNMs from palm oil and future recommendations are also highlighted. Generally, this paper could be a handy guide in assisting the researchers in exploring economic yet simple procedures in synthesizing carbon-based nanostructured materials derived from palm oil that can fulfill the required applications.

GRAPHICAL ABSTRACT

Nitrogen, phosphorus co-doped hollow porous carbon microspheres as an oxidase-like electrochemical sensor for baicalin

The extraordinary properties and unique structure of porous carbon has rapidly turned into a new favorite in the development and application of high-performance electrocatalytic sensor. Nitrogen, phosphorus co-doped hollow porous...

Nitrogen-Doped Porous Carbon Nanospheres Activated under Low ZnCl2 Aqueous System: An Electrode for Supercapacitor Applications

We reported a controlled synthesis method to obtained carbon spheres with tunable geometry under low ZnCl₂ aqueous solution conditions using polytriazine as a precursor. The polytriazine precursor was polymerized by mixing/reaction of 2,6-diaminopyridine and formaldehyde in the presence of a diluted ZnCl₂ aqueous system. The obtained nanospheres were then decomposed to adulterate nitrogen porous carbon nanospheres (N-PCNSs) by the decomposition and blistering process at high temperature by degrees. ZnCl₂ worked as a solid-template and played the role of a stabilizing and foaming agent in the reaction. The as-prepared N-PCNSs with controllable spherical geometry, large micro-/mesoporous volume and high nitrogen content (∼8.5 wt %) were employed in electric double-layer capacitors that have a good specific capacitance (636 F/g at 1 A/g) and are long lasting. Besides, the N-PCNS delivered a high energy density of 22.1 Wh/Kg at a power density of 500 W/kg.

One-step green fabrication of hierarchically porous hollow carbon nanospheres (HCNSs) from raw biomass: Formation mechanisms and supercapacitor applications

Hierarchical porous hollow carbon nanospheres (HCNSs) were fabricated directly from raw biomass via a one-step method, in which HCNSs were obtained by thermal treatment of raw biomass in the presence of polytetrafluoroethylene (PTFE). The HCNSs possess coupling merits of uniformly distributed hollow spherical architectures, and high specific surface area, abundant accessible/open micropores and reasonable mesopores, the HCNS-based electrodes deliver high electrochemical capacitance. The formation mechanisms of pores and hollow core-shell structures were explored thoroughly, it is found that the key to the formation of hollow core-shell structure is the onset-pyrolysis temperature difference between raw biomass and PTFE. Moreover, the content of silica had significant effects on the textures of HCNSs, and HCNS with the largest SSA of 1984 m²/g was obtained. Accordingly, a possible mechanism of HCNSs formation was proposed here, where PTFE acted as the pore creation and nucleation agents and raw biomasses were the primary carbon precursors.

Deep-eutectic-solvent synthesis of N/O self-doped hollow carbon nanorods for efficient energy storage

N/O self-doped hollow carbon nanorods (HCNs) with micro/mesoporous walls are fabricated based on a new deep-eutectic-solvent that serves as an all-in-one precursor, self-template, and self-dopant agent. The carbon-based supercapacitor using an ionic liquid electrolyte exhibits a high energy density of 116.5 W h kg-1 with excellent long-term cycling performance.

Recent Advances in Organic Thermoelectric Materials: Principle Mechanisms and Emerging Carbon-Based Green Energy Materials

Thermoelectric devices have recently attracted considerable interest owing to their unique ability of converting heat to electrical energy in an environmentally efficient manner. These devices are promising as alternative power generators for harvesting electrical energy compared to conventional batteries. Inorganic crystalline semiconductors have dominated the thermoelectric material fields; however, their application has been restricted by their intrinsic high toxicity, fragility, and high cost. In contrast, organic thermoelectric materials with low cost, low thermal conductivity, easy processing, and good flexibility are more suitable for fabricating thermoelectric devices. In this review, we briefly introduce the parameters affecting the thermoelectric performance and summarize the most recently developed carbon-material-based organic thermoelectric composites along with their preparation technologies, thermoelectric performance, and future applications. In addition, the p- and n-type carbon nanotube conversion and existing challenges are discussed. This review can help researchers in elucidating the recent studies on carbon-based organic thermoelectric materials, thus inspiring them to develop more efficient thermoelectric devices.