Binbin Zhang

N-doped carbon aerogels have garnered increasing research interest in the field of energy and environment due to their unique structural features. Organic dyes, which contain redox-active sites and act as pollutants, are attractive candidates for cathode materials in Li-ion batteries but still suffer from poor cycle stability and rate performance. Therefore, there is still a lack of an easy and effective approach to rationally design the pore structure of N-doped carbon aerogels for efficiently and stably trapping dye molecules and converting them into high-performance cathode materials. Herein, we propose an innovative strategy for preparing nitrogen-doped carbon aerogels with a well-defined micropore structure (MNCAs) for efficient adsorption of dye molecules, subsequently converting them into high-performance lithium-ion battery cathode materials. MNCAs were synthesized via Schiff-based polymerization using polyhedral oligomeric silsesquioxane (POSS) as a template, resulting in a carbon framework with well-defined micropores. Benefiting from their high specific surface area and well-defined micropore structure, MNCAs exhibited a maximum adsorption capacity at equilibrium of 2273 mg g⁻¹ for indigo. Notably, the indigo@nitrogen-doped carbon aerogel composite (IDG@MNCAs) exhibits high specific capacity, outstanding cycling stability, and remarkable rate capability. The discharge specific capacity of IDG@MNCAs retains 89% of its capacity (120 mAh g⁻¹) after 200 cycles at 100 mA g⁻¹ and maintains 70% capacity retention after 1200 cycles at the higher current density of 1000 mA g⁻¹, surpassing many recently reported organic cathode materials.

Fe-N-C materials have been regarded as one of the potential candidates to replace traditional noble-metal-based electrocatalysts for the oxygen reduction reaction (ORR). It is believed that the structure of carbon support in Fe-N-C materials plays an essential role in highly efficient ORR. However, precisely designing the morphology and surface chemical structure of carbon support remains a challenge. Herein, we present a novel synthetic strategy for the preparation of porous carbon spheres (PCSs) with high specific surface area, well-defined pore structure, tunable morphology and controllable heteroatom doping. The synthesis involves Schiff-based polymerization utilizing octaaminophenyl polyhedral oligomeric silsesquioxane (POSS-NH₂) and heteroatom-containing aldehydes, followed by pyrolysis and HF etching. The well-defined pore structure of PCS can provide the confinement field for ferroin and transform into Fe-N-C sites after carbonization. The tunable morphology of PCS can be easily achieved by changing the solvents. The surface chemical structure of PCS can be tailored by utilizing different heteroatom-containing aldehydes. After optimizing the structure of PCS, Fe-N-C loading on N,S-codoped porous carbon sphere (NSPCS-Fe) displays outstanding ORR activity in alkaline solution. This work paves a new path for fabrication of Fe-N-C materials with the desired morphology and well-designed surface chemical structure, demonstrating significant potential for energy-related applications.

Compared with common chemical oxidation polymerization reactions, the electrochemical polymerization method has seldom been employed for the preparation of high-performance polymer thermoelectric composites, although it has obvious advantages of film product and highly tunable functions. Herein, we reported a novel preparation strategy, i.e. the combination of dynamic 3-phase interfacial electropolymerization for poly(3,4-ethylenedioxythiophene) (PEDOT) and the chemical doping of single-walled carbon nanotubes (SWCNTs), to fabricate flexible films of their thermoelectric composites. The acid-doped SWCNTs (a-SWCNTs) displayed a significantly enhanced electrical conductivity and a reduced Seebeck coefficient. The PEDOT/a-SWCNT composites exhibit excellent power factors with the maxima of 350.0 ± 47.6 μW m⁻¹ K⁻² at room temperature, and even as high as 510.2 μW m⁻¹ K⁻² at 412 K. More importantly, the thermoelectric performance can be conveniently tuned by various parameters, such as the a-SWCNT content, and electropolymerization conditions including the type and loading of the PEDOT counter ions. The present study proposes a new design strategy to fabricate high-performance polymer thermoelectric composites and facilitates the application of organic/inorganic thermoelectric composites.

A novel method to prepare high-quality graphene is developed using simple calcination of a mixture of glucose and FeCl₃.

Hydrogenation of ester levulinate to gamma-valerolactone (GVL) is an interesting reaction in biomass conversion to produce value-added chemicals. Exploration of efficient and robust catalysts is crucial for large-scale application. In this work, we conducted the reaction catalyzed by a Co catalyst, and it was found that commercially available Co₃O₄ was very efficient for this reaction under mild conditions after reduction by H₂. The effects of temperature, hydrogen pressure, amount of the catalyst used, and reaction time on the yield of GVL were studied. Under optimized conditions, the yield of GVL could reach 98%. The catalyst could be reused at least 10 times without notable loss of the activity and selectivity. The catalyst was characterized by scanning electron spectroscopy (SEM), transmission electron spectroscopy (TEM), X-ray photoelectron spectroscopy (XPS), and powder X-ray diffraction (XRD). It was demonstrated that the metallic Co⁰ was the active species for the hydrogenation reaction. As far as we know, this is the first work conducting the reaction using Co as the catalyst.

Efficient conversion of glucose to 5-hydroxymethylfurfural (HMF), an important platform molecular for fuels and chemicals, is a promising topic in green chemistry. In this work, several new DBU-based (DBU = 1,8-diazabicyclo[5.4.0]undec-7-ene) ionic liquids (ILs) with benzene sulfonate (BS) anion were synthesized and used as the solvents for the dehydration of glucose to HMF. It was found that all the ILs were excellent solvents for the dehydration of glucose to form HMF using CrCl₃ as the catalyst. The effects of various factors, such as kind of catalysts, catalyst amount, reaction time and reaction temperature, on the yields of HMF were studied systematically in the Et-DBUBS/CrCl₃ catalytic system. The yield of HMF from glucose could reach 83.4% under the optimized reaction conditions, and the reasons for the high yield were investigated on the basis of control experiments. The Et-DBUBS/CrCl₃ system could be reused at least five times without considerable reduction in the efficiency. Further study indicated that the catalytic system was also very efficient for transformation of fructose, inulin, and cellobiose to HMF.