The Calculation of Both Electrostatic and Van der Waals Effects to Probe the Efficiency of Solvent Extraction of Heterocyclic Aromatics from Heavy Oil.

Due to the complex composition and similar structure, the extraction denitrification of aromatic rich oil is faced with the contradiction problem of denitrification efficiency and aromatic loss which cannot be efficiently solved by experiments. However, the complex interactions involved can be analyzed from the perspective of calculation, and the prediction criteria and methods are proposed. Based on rigorous density functional theory calculation data, Simple models based on electrostatic potential (ESP) and Van der Waals potential (VdWP)-based calculations were established and validated. The twofold model provided the best prediction for interactions between extractants and nitrogen compounds and between extractants and aromatics, which determines denitrification efficiency and aromatic loss, respectively, due to the most complete description of both electrostatic and VdW force. This provides a powerful tool for evaluating the non-covalent interactions and thence tuning the efficiency of the separation process. Thus, high denitrification efficiency (43.2~66.3 %) and moderate aromatic loss (1.7~4.4 %) were obtained using screened deep eutectic solvents (DESs). This ideal observation provided the potential for mild hydrodesulfurization and manufacture of high-grade carbon materials.

A review of catalytic hydrogenation of carbon dioxide: From waste to hydrocarbons.

With the rapid development of industrial society and humankind's prosperity, the growing demands of global energy, mainly based on the combustion of hydrocarbon fossil fuels, has become one of the most severe challenges all over the world. It is estimated that fossil fuel consumption continues to grow with an annual increase rate of 1.3%, which has seriously affected the natural environment through the emission of greenhouse gases, most notably carbon dioxide (CO2). Given these recognized environmental concerns, it is imperative to develop clean technologies for converting captured CO2 to high-valued chemicals, one of which is value-added hydrocarbons. In this article, environmental effects due to CO2 emission are discussed and various routes for CO2 hydrogenation to hydrocarbons including light olefins, fuel oils (gasoline and jet fuel), and aromatics are comprehensively elaborated. Our emphasis is on catalyst development. In addition, we present an outlook that summarizes the research challenges and opportunities associated with the hydrogenation of CO2 to hydrocarbon products.

A Carbon Catalyst Co-Doped with P and N for Efficient and Selective Oxidation of 5-Hydroxymethylfurfural into 2,5-Diformylfuran.

A newly designed N and P co-doped carbon material has been developed to catalyze the conversion of 5-hydroxymethylfurfural (HMF) to 2,5-furandialdehyde (DFF) with unprecedented yield and selectivity and demonstrating a synergistic effect between the heteroatoms. The desired catalyst was first synthesized via a pyrolysis method using urea as the nitrogen and carbon source followed by calcination with phytic acid solution as the phosphorus source. The mass ratio of phytic acid to C3 N4 and calcination temperature were varied to investigate their effects on catalyst synthesis and microstructure as well as subsequent catalytic activity in simple reaction systems under oxygen. The effect of reaction conditions on the final HMF conversion and DFF selectivity were also investigated systematically. The P-C-N-5-800 catalyst obtained with the optimized annealing temperature of 800 °C and mass ratio of phytic acid/C3 N4 of 5 enabled a 99.5 % DFF yield at 120 °C for 9 h under 10 bar oxygen pressure, being the highest among any reported metal-free heterogeneous catalyst to date. The excellent performance of P-C-N-5-800 could be ascribed to the synergy between N and P heteroatoms as well as the high content of graphitic-N and the P-C species within the carbon structure. Reusability studies show that the P-C-N-5-800 catalyst was stable and reusable without deactivation. These results strongly suggest that P-C-N-5-800 is a promising catalyst for large-scale production of DFF in a green manner.

Built-In Catalysis in Confined Nanoreactors for High-Loading Li-S Batteries.

A cathode host with strong sulfur/polysulfide confinement and fast redox kinetics is a challenging demand for high-loading lithium-sulfur batteries. Recently, porous carbon hosts derived from metal-organic frameworks (MOFs) have attracted wide attention due to their unique spatial structure and customizable reaction sites. However, the loading and rate performance of Li-S cells are still restricted by the disordered pore distribution and surface catalysis in these hosts. Here, we propose a concept of built-in catalysis to accelerate lithium polysulfide (LiPSs) conversion in confined nanoreactors, i.e., laterally stacked ordered crevice pores encompassed by MoS2-decorated carbon thin layers. The functions of S-fixability and LiPS catalysis in these mesoporous cavity reactors benefit from the 2D interface contact between ultrathin catalytic MoS2 and conductive C pyrolyzed from Al-MOF. The integrated function of adsorption-catalysis-conversion endows the sulfur-infused C@MoS2 electrode with a high initial capacity of 1240 mAh g-1 at 0.2 C, long life cycle stability of at least 1000 cycles at 2 C, and high rate endurance up to 20 C. This electrode also exhibits commercial potential in view of considerable capacity release and reversibility under high sulfur loading (6 mg cm-2 and ∼80 wt %) and lean electrolyte (E/S ratio of 5 µL mg-1). This study provides a promising design solution of a catalysis-conduction 2D interface in a 3D skeleton for high-loading Li-S batteries.

Adenine Derivative Host with Interlaced 2D Structure and Dual Lithiophilic-Sulfiphilic Sites to Enable High-Loading Li-S Batteries.

How to simultaneously restrain the loss of active species and facilitate the conversion reaction under high S loading condition is the key to solve the commercialization of Li-S batteries. For this system, the availability of raw materials and simplicity (high efficiency) of synthetic strategies are also important factors. Herein, we propose an interlaced two-dimensional (2D) carbon material as advanced Li-S cathode host characterized by corrugated monolithic morphology and Co/N dopants as dual lithiophilic-sulfiphilic sites. This 2D structure is derived from a cheap biomass precursor, adenine, with bonding interaction with a MgCl2 hydrate template via a facile ionothermal method. It allows a homogeneous spatial distribution of S/Li2S deposits and strong adsorbability and enhanced conversion kinetics for polysulfides. Benefiting from the synergistic effects of corrugated 2D conductive matrix and embedded heteroatom/nanodot catalyst, the resultant sulfur cathode releases a high specific capacity of 1290.4 mA h g-1 at 0.2 C, small capacity fading rate of 0.029% per cycle over 600 cycles at 2 C, superior rate performance up to 20 C, and considerable areal capacity retention of 6.0 mA h cm-2 even under an ultrahigh sulfur loading up to 9.7 mg cm-2.

Rapid, non-invasive characterization of the dispersity of emulsions via microwaves.

A rapid and non-invasive method to determine the dispersity of emulsions is developed based on the interrelationship between the droplet size distribution and the dielectric properties of emulsions. A range of water-in-oil emulsions with different water contents and droplet size distributions were analysed using a microwave cavity perturbation technique together with dynamic light scattering. The results demonstrate that the dielectric properties, as measured by non-invasive microwave cavity analysis, can be used to characterise the dispersity of emulsions, and is also capable of characterizing heavy oil emulsions. This technique has great potential for industrial applications to examine the sedimentation, creaming and hence the stability of emulsions.