Nanoporous Carbons: Looking Beyond Their Perception as Adsorbents, Catalyst Supports and Supercapacitors

High-performance sodium-ion batteries using Na5PV2Mo10O40 modified reduced graphene oxide (rGO) composite materials induced by imidazole ionic liquids

Sodium-ion batteries (SIBs) have gained increasing attention as a promising alternative to lithium-ion batteries, owing to the abundance and low cost of sodium. However, despite these advantages, the performance of SIBs is hindered by the larger ionic radius of sodium, which not only reduces ion migration rates but also significantly decreases the specific capacity. To address this challenge, the present study explores the synthesis of Na5PV2Mo10O40 (PV2Mo10)-modified reduced graphene oxide (rGO) composites by employing imidazole ionic liquid (IL) as electrostatic attraction agent, this approach not only prevents the aggregation of polyoxometalates (POMs) but also increases the interlayer distance of rGO, improving the battery's specific capacity and enhancing the diffusion rate of Na+ ions. Experimental results indicate that the PV2Mo10-rGO-IL hybrid material exhibits exceptional electrochemical properties, characterized by significantly improved conductivity and an impressive specific capacity of 290mAh g-1 while achieving nearly 100 % Coulombic efficiency over 900 cycles. Furthermore, theoretical calculations reveal that the incorporation of POMs effectively reduces the electrode impedance of rGO and enhances the structural stability of POMs during cycling. This study opens up new avenues for the design of high-performance sodium ion batteries based on POMs.

Surface chemistry and catalytic activity in H2O2 decomposition of pyrolytically fluoralkylated activated carbons

According to the proposed pyrolytic method, granular activated carbon (AC) Norit 830 W was functionalized by thermal treatment of AC in hydrofluorocarbon (HFC) gases, pentafluoroethane and 1,1,1,2-tetrafluoroethane, at 400-800 °C. This method does not require activation by plasma and photons. Chemical and elemental analysis showed that the pyrolytic treatment provides a loading of 2.95 mmol (5.6 wt%) of fluorine per gram of AC. Nitrogen adsorption measurements indicated that the microporous structure contracted when AC was treated with HFC at temperatures above 400 °C. Thermogravimetry, Fourier transform infrared spectroscopy (FTIR) with attenuated total reflectance (ATR), and X-ray photoelectron spectroscopy (XPS) demonstrated the evolution of oxygen-containing and fluorine-containing groups to more thermostable groups with treatment temperature. The fluorine-containing groups grafted at high temperature, above 600 °C exhibited the highest thermal stability up to 1250 °C in dry argon. From the data of XPS and solid-state 19F nuclear magnetic resonance spectroscopy data, the grafted fluorine exists in several types of grafted F-containing groups, the HFC residues. By changing the thermal regime of fluorination, the composition of fluorine-containing groups on a carbon surface can be regulated. Isolated fluoroalkyl groups can be grafted at temperatures of 400-500 °C, while at 600 °C and above, the semi-ionic fluorine groups increase significantly. The hydrophobized surface demonstrated the ability to effectively decompose H2O2 in methanol solutions.

Covalent Organic Framework Based Nanocomposite for Low Temperature Photothermal Therapy

Triple negative breast cancer (TNBC) represents a highly aggressive variant of breast cancer characterized by elevated rates of recurrence and mortality. Chemotherapy's application as a main cancer therapy is restricted due to its harmful side effects and resistance to medication. In this study, we utilized a covalent organic framework (COF) to apply indocyanine green (ICG), a photothermal agent, and gambogic acid (GA), an inhibitor of heat shock protein 90 (HSP90), to treat triple negative breast cancer. MTT results showed that the viability of tumor cells decreased more under laser irradiation conditions after the addition of GA than in the COF@ICG group. In addition, protein blotting results showed that under the action of GA, the blank group exhibited significantly higher HSP90 expression levels than the experimental group. The above results indicate that COF@ICG@GA enhances the therapeutic effect of PTT on cancer by inhibiting the expression of HSP90 in triple negative breast cancer cells and enhancing the sensitivity of tumor cells to temperature.

Effective adsorption of zeolite/carbon composite molecular sieve synthesized from spent bleaching earth

Spent bleaching earth (SBE) as an industrious solid rubbish seriously causes the environmental pollution problem. The resourceful utilization of SBE has become increasingly important. In this work, silicon and carbon ingredients derived from SBE were coincidently employed to synthesize a 4A zeolite/carbon composite molecular sieve (4A/CMS). Therein, the graphite carbon components in the form of porous lamellar scattering among the interlayer, surface, and periphery of 4A zeolite promote the rate of mass transfer for the lipophilic gas, which can effectively improve the adsorption property for the volatile organic compounds. The obtained 4A/CMS has large specific surface area, hierarchical pore structure, satisfactory adsorption capacity, and regeneration performance, and its equilibrium adsorption capacity of p-xylene can achieve 209.57 mg·g^-1. The pseudo-first-order rate equation is appropriate for the adsorption kinetics. In the end, the formation mechanism of 4A/CMS was illuminated in detail. □ Spent bleaching earth (SBE) as an industrious solid rubbish were utilized resourcefully. Silicon and carbon ingredients from SBE were coincidently employed to synthesize 4A/CMS. Graphitic carbon with hierarchical pore promoted the rate of mass transfer of organic gas. 4A/CMS exhibited excellent adsorption capacity and regeneration performance of p-xylene.

Graphene Oxyhydride Catalysts in View of Spin Radical Chemistry

This article discusses carbocatalysis that are provided with amorphous carbons. The discussion is conducted from the standpoint of the spin chemistry of graphene molecules, in the framework of which the amorphous carbocatalysts are a conglomerate of graphene-oxynitrothiohydride stable radicals presenting the basic structure units (BSUs) of the species. The chemical activity of the BSUs atoms is reliably determined computationally, which allows mapping the distribution of active sites in these molecular catalysts. The presented maps reliably show the BSUs radicalization provided with carbon atoms only, the nonterminated edge part of which presents a set of active sites. Spin mapping of carbocatalysts active sites is suggested as the first step towards the spin carbocatalysis of the species.

Sustainability in Catalytic Cyclohexane Oxidation: The Contribution of Porous Support Materials

The development of green and sustainable protocols for synthetic routes is a growing area of research in chemistry worldwide. The development of sustainable processes and products through innovative catalytic materials and technologies, that allow a better use of resources, is undoubtedly a very important issue facing research chemists today. Environmentally and economically advanced catalytic processes for selective alkane oxidations reactions, as is the case of cyclohexane oxidation, are now focused on catalysts’ stability and their reuse, intending to overcome the drawbacks posed by current homogeneous systems. The aim of this short review is to highlight recent contributions in heterogeneous catalysis regarding porous support materials to be applied to cyclohexane oxidation reaction. Different classes of porous materials are covered, from carbon nanomaterials to zeolites, mesoporous silicas, and metal organic frameworks. The role performed by the materials to be used as supports towards an enhancement of the activity/selectivity of the catalytic materials and the ability of recycling and reuse in consecutive catalytic cycles is highlighted.

Importance of Carbon Porosity for Energy-Related Applications

Nanoporous carbons have many advantages over other adsorbents. This includes their high surface area, pore volume and also conductivity of a carbon matrix. The latter is very important for electrocatalysis. In recent years carbon materials have gained a lot of attention as metal-free catalysts. Their catalytic centers have been linked mainly to nitrogen and sulfur heteroatoms incorporated to the carbon matrix. So far, the research efforts have focused mainly on nanoforms of carbons such a graphene and carbon nanotube (CNT). Inspired by those results, we have performed CO2 and O2 electroreduction on nanoporous carbons assuming that small pores, similar in sizes to target molecules, can enhance the efficiency of these catalytic processes. Indeed, the results suggested that even though the N- and S- based catalytic centers are important, adsorption of O2 or CO2/CO2-/CO/H2 in pores has a positive effect on these overall reduction processes. This minireview summarizes our recent results on the role of porosity in electrocatalysis on porous carbons.

Origin and Perspectives of the Photochemical Activity of Nanoporous Carbons

Even though, owing to the complexity of nanoporous carbons' structure and chemistry, the origin of their photoactivity is not yet fully understood, the recent works addressed here clearly show the ability of these materials to absorb light and convert the photogenerated charge carriers into chemical reactions. In many aspects, nanoporous carbons are similar to graphene; their pores are built of distorted graphene layers and defects that arise from their amorphicity and reactivity. As in graphene, the photoactivity of nanoporous carbons is linked to their semiconducting, optical, and electronic properties, defined by the composition and structural defects in the distorted graphene layers that facilitate the exciton splitting and charge separation, minimizing surface recombination. The tight confinement in the nanopores is critical to avoid surface charge recombination and to obtain high photochemical quantum yields. The results obtained so far, although the field is still in its infancy, leave no doubts on the possibilities of applying photochemistry in the confined space of carbon pores in various strategic disciplines such as degradation of pollutants, solar water splitting, or CO2 mitigation. Perhaps the future of photovoltaics and smart-self-cleaning or photocorrosion coatings is in exploring the use of nanoporous carbons.