Mesoporous carbon hollow spheres encapsulated phase change material for efficient emulsification of high-viscosity oil

A Novel Electrochemical Sensor Based on Pd Confined Mesoporous Carbon Hollow Nanospheres for the Sensitive Detection of Ascorbic Acid, Dopamine, and Uric Acid

In this study, we designed a novel electrochemical sensor by modifying a glass carbon electrode (GCE) with Pd confined mesoporous carbon hollow nanospheres (Pd/MCHS) for the simultaneous detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The structure and morphological characteristics of the Pd/MCHS nanocomposite and the Pd/MCHS/GCE sensor are comprehensively examined using SEM, TEM, XRD and EDX. The electrochemical properties of the prepared sensor are investigated through CV and DPV, which reveal three resolved oxidation peaks for AA, DA, and UA, thereby verifying the simultaneous detection of the three analytes. Benefiting from its tailorable properties, the Pd/MCHS nanocomposite provides a large surface area, rapid electron transfer ability, good catalytic activity, and high conductivity with good electrochemical behavior for the determination of AA, DA, and UA. Under optimized conditions, the Pd/MCHS/GCE sensor exhibited a linear response in the concentration ranges of 300-9000, 2-50, and 20-500 µM for AA, DA, and UA, respectively. The corresponding limit of detection (LOD) values were determined to be 51.03, 0.14, and 4.96 µM, respectively. Moreover, the Pd/MCHS/GCE sensor demonstrated outstanding selectivity, reproducibility, and stability. The recovery percentages of AA, DA, and UA in real samples, including a vitamin C tablet, DA injection, and human urine, range from 99.8-110.9%, 99.04-100.45%, and 98.80-100.49%, respectively. Overall, the proposed sensor can serve as a useful reference for the construction of a high-performance electrochemical sensing platform.

Anisotropic Rotunda-Shaped Carboxymethylcellulose/Carbon Nanotube Aerogels Supported Phase Change Materials for Efficient Solar-Thermal Energy Conversion

For the drawbacks of phase change materials such as poor shape stability and weak solar-thermal conversion ability, a rotunda-shaped carboxymethylcellulose/carbon nanotube aerogel (CA) with three-dimensional network was constructed by freeze casting with a special mold, and then impregnated with polyethylene glycol (PEG) in this work. The PEG/CA had an enthalpy of 183.21 J/g, and a thermal conductivity of 0.324 W m-1 K-1, which was 57 % higher than the pure PEG. The ability of PEG/CA to convert solar energy to thermal energy was a positive correlation between the inclusion of CNTs and the composite material's thermal conductivity. Under simulated sunlight, its solar-thermal conversion efficiency reaches 94.41 %, and after 10 min of irradiation, the surface temperature can reach 65 °C and the internal temperature can reach 44.67 °C. This rotunda-shaped PEG/CA is promising for the efficient use of renewable solar energy due to its strong solar-thermal conversion and thermal storage capabilities.

Hollow carbon-based materials for electrocatalytic and thermocatalytic CO2 conversion

Electrocatalytic and thermocatalytic CO2 conversions provide promising routes to realize global carbon neutrality, and the development of corresponding advanced catalysts is important but challenging. Hollow-structured carbon (HSC) materials with striking features, including unique cavity structure, good permeability, large surface area, and readily functionalizable surface, are flexible platforms for designing high-performance catalysts. In this review, the topics range from the accurate design of HSC materials to specific electrocatalytic and thermocatalytic CO2 conversion applications, aiming to address the drawbacks of conventional catalysts, such as sluggish reaction kinetics, inadequate selectivity, and poor stability. Firstly, the synthetic methods of HSC, including the hard template route, soft template approach, and self-template strategy are summarized, with an evaluation of their characteristics and applicability. Subsequently, the functionalization strategies (nonmetal doping, metal single-atom anchoring, and metal nanoparticle modification) for HSC are comprehensively discussed. Lastly, the recent achievements of intriguing HSC-based materials in electrocatalytic and thermocatalytic CO2 conversion applications are presented, with a particular focus on revealing the relationship between catalyst structure and activity. We anticipate that the review can provide some ideas for designing highly active and durable catalytic systems for CO2 valorization and beyond.

Coupling Carbon-Based Composite Phase Change Materials with a Polyurethane Sponge for Sustained and Efficient Solar-Driven Cleanup of Viscous Crude Oil Spill

The efficient cleanup of crude oil spills is a worldwide problem due to their high viscosity and low fluidity. Under the assistance of solar radiation, adsorbents with in situ heating function are becoming the ideal candidates to solve this problem. In this study, a new strategy coupling a polyurethane (PU) sponge with phase change materials (PCMs) is proposed to realize the efficient utilization of solar energy and crude oil cleanup. Wormlike carbon nanotubes/mesoporous carbon (CNTs/MC) with a core-shell structure was used to encapsulate polyethylene glycol (PEG), which was then introduced into the PU sponge for photothermal conversion and thermal storage. After coating with a polydimethylsiloxane (PDMS) layer, the sponge was further endowed with hydrophobic characteristics. Additionally, PDMS can function as a binder between PEG@CNTs/MC and sponge skeleton. The resulting PEG@CNTs/MC/PU/PDMS (named as PEG@CMPP) exhibited excellent photothermal conversion and high absorption capacity for high-viscosity crude oil. Most importantly, thanks to the heat storage properties of PEG, the stored heat can be sustainably transferred to the surrounding crude oil to promote its continuous absorption even under insufficient light intensity conditions. The crude oil absorption capacity of PEG@CMPP-3 reached approximately 0.96 g/cm3 even after the light source was removed, which manifested the distinctive advantages compared to the conventional photothermal adsorbent. The proposed approach integrates the high efficiency of solar-assisted heating and energy-conserving advantage, thereby providing a feasible strategy for highly efficient remediation of viscous crude oil spills.

New Porous Carbon Material Derived from Carbon Microspheres Assembled in Hollow Carbon Spheres and Its Application to Toluene Adsorption

In this paper, a new porous carbon material adsorbent was prepared using carbon microspheres assembled in hollow carbon spheres (HCS) with a hydrothermal method. Transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and Raman spectroscopy were used to characterize the adsorbents. It was found that the diameter of carbon microspheres derived from 0.1 mol/L glucose was about 130 nm, which could be inserted inside HCS (pore size was 370-450 nm). The increase in glucose concentration would promote the diameter of carbon microspheres (CSs), and coarse CSs could not be loaded in the mesopores or macropores of HCS. Thus, the C_0.1@HCS adsorbent had the highest Brunauer-Emmett-Teller surface area (1945 m²/g) and total pore volume (1.627 cm³/g). At the same time, C_0.1@HCS posed a suitable ratio of micropores and mesopores, which could provide adsorption sites and volatile organic compound diffusion channels. Moreover, oxygen-containing functional groups -OH and C═O in CSs were also introduced into HCS, and the adsorption capacity and regenerability performance of the adsorbents were improved. The dynamic adsorption capacity of C_0.1@HCS for toluene reached 813 mg/g, and the Bangham model was more suitable for describing the toluene adsorption process. The adsorption capacity was stably kept above 770 mg/g after eight adsorption-desorption cycles.