Carbon Nanomaterials With Hollow Structures: A Mini-Review

Upcycling of Waste Plastic into Hybrid Carbon Nanomaterials

Graphitic 1D and hybrid nanomaterials represent a powerful solution in composite and electronic applications due to exceptional properties, but large-scale synthesis of hybrid materials has yet to be realized. Here, a rapid, scalable method to produce graphitic 1D materials from polymers using flash Joule heating (FJH) is reported. This avoids lengthy chemical vapor deposition and uses no solvent or water. The flash 1D materials (F1DM), synthesized using a variety of earth-abundant catalysts, have controllable diameters and morphologies by parameter tuning. Furthermore, the process can be modified to form hybrid materials, with F1DM bonded to turbostratic graphene. In nanocomposites, F1DM outperform commercially available carbon nanotubes. Compared to current 1D material synthetic strategies using life cycle assessment, FJH synthesis represents an 86-92% decrease in cumulative energy demand and 92-94% decrease in global-warming potential. This work suggests that FJH affords a cost-effective and sustainable route to upcycle waste plastic into valuable 1D and hybrid nanomaterials.

Design of Uniform Hollow Carbon Nanoarchitectures: Different Capacitive Deionization between the Hollow Shell Thickness and Cavity Size

Carbon-based materials with high capacitance ability and fast electrosorption rate are ideal electrode materials in capacitive deionization (CDI). However, traditional carbon materials have structural limitations in electrochemical and desalination performance due to the low capacitance and poor transmission channel of the prepared electrodes. Therefore, reasonable design of electrode material structure is of great importance for achieving excellent CDI properties. Here, uniform hollow carbon materials with different morphologies (hollow carbon nanospheres, hollow carbon nanorods, hollow carbon nano-pseudoboxes, hollow carbon nano-ellipsoids, hollow carbon nano-capsules, and hollow carbon nano-peanuts) are reasonably designed through multi-step template method and calcination of polymer precursors. Hollow carbon nanospheres and hollow carbon nano-pseudoboxes exhibit better capacitance and higher salt adsorption capacity (SAC) due to their stable carbonaceous structure during calcination. Moreover, the effects of the thickness of the shell and the size of the cavity on the CDI performance are also studied. HCNSs-0.8 with thicker shell (≈20 nm) and larger cavity (≈320 nm) shows the best SAC value of 23.01 mg g-1 due to its large specific surface area (1083.20 m2  g-1 ) and rich pore size distribution. These uniform hollow carbon nanoarchitectures with functional properties have potential applications in electrochemistry related fields.

Hollow-Structured Microporous Organic Networks Adsorbents Enabled Specific and Sensitive Identification and Determination of Aflatoxins

Aflatoxin (AFT) contamination, commonly in foods and grains with extremely low content while high toxicity, has caused serious economic and health problems worldwide. Now researchers are making an effort to develop nanomaterials with remarkable adsorption capacity for the identification, determination and regulation of AFT. Herein, we constructed a novel hollow-structured microporous organic networks (HMONs) material. On the basis of Fe3O4@MOF@MON, hydrofluoric acid (HF) was introduced to remove the transferable metal organic framework (MOF) to give hollow MON structures. Compared to the original Fe3O4@MOF@MON, HMON showed improved surface area and typical hollow cavities, thus increasing the adsorption capacity. More importantly, AFT is a hydrophobic substance, and our constructed HMON had a higher water contact angle, greatly enhancing the adsorption affinity. From that, the solid phase extraction (SPE-HPLC) method developed based on HMONs was applied to analyze four kinds of actual samples, with satisfied recoveries of 85-98%. This work provided a specific and sensitive method for the identification and determination of AFT in the food matrix and demonstrated the great potential of HMONs in the field of the identification and control of mycotoxins.

Artemisinin-Type Drugs in Tumor Cell Death: Mechanisms, Combination Treatment with Biologics and Nanoparticle Delivery

Artemisinin, the most famous anti-malaria drug initially extracted from Artemisia annua L., also exhibits anti-tumor properties in vivo and in vitro. To improve its solubility and bioavailability, multiple derivatives have been synthesized. However, to reveal the anti-tumor mechanism and improve the efficacy of these artemisinin-type drugs, studies have been conducted in recent years. In this review, we first provide an overview of the effect of artemisinin-type drugs on the regulated cell death pathways, which may uncover novel therapeutic approaches. Then, to overcome the shortcomings of artemisinin-type drugs, we summarize the recent advances in two different therapeutic approaches, namely the combination therapy with biologics influencing regulated cell death, and the use of nanocarriers as drug delivery systems. For the former approach, we discuss the superiority of combination treatments compared to monotherapy in tumor cells based on their effects on regulated cell death. For the latter approach, we give a systematic overview of nanocarrier design principles used to deliver artemisinin-type drugs, including inorganic-based nanoparticles, liposomes, micelles, polymer-based nanoparticles, carbon-based nanoparticles, nanostructured lipid carriers and niosomes. Both approaches have yielded promising findings in vitro and in vivo, providing a strong scientific basis for further study and upcoming clinical trials.

Constructing Porous Carbon Electrocatalysts from Cobalt Complex-Decorated Micelles of Mesoporous Silica for Oxygen Reduction/Evolution Reaction

The construction of a porous carbon structure with a high specific surface area is conducive to enhanced electrocatalytic activity due to the accessibility of active sites and improvement of the mass transfer. Herein, we explored the possibility of using micelles of mesoporous silica (MCM-48) as the carbon source to generate porous carbon under the confinement of MCM-48 channels. The complexes formed by Co²⁺ and 4,4'-bipyridine were in situ incorporated into the micelles to derive Co-related active sites (Co-N_x, Co, and Co₃O₄) for catalyzing the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). After pyrolysis in the N₂ atmosphere and subsequent removal of the MCM-48 skeleton, the target porous carbon electrocatalyst was obtained, which exhibited promising performance for both ORR and OER and has great potential as the cathode material for Zn-air battery application. This work not only confirms the effectiveness of using the micelles of MCM-48 as the carbon source for preparing the porous carbon materials, but also provides a new platform for design and synthesis of structurally controllable materials for energy-related electrocatalytic applications.