Congshan Zhou’s research while affiliated with Hunan Institute of Science and Technology and other places

With the widespread use of gold as a precious metal, the recovery of gold has become an urgent problem to be solved. Therefore, the design and preparation of a sorbent with better adsorbability and higher selectivity for Au(iii) is of great significance for recovering gold resources and protecting the environment. In order to obtain an efficient and stable gold ion sorbent, N1,N1′-(1,4-phenylene)bis(N1-(4-aminophenyl)benzene-1,4-diamine) and 2,4,6-tricarboxylisophene were cross-linked by a solvent thermal reaction to synthesize a double-functional covalent organic polymer (N-TPCOP). The N-TPCOP has a very high gold uptake capacity of 3400.38 mg g⁻¹, because it reduces Au(iii) to elemental gold by sequestration and redox reactions between functional atoms (N and O) and Au(iii). In summary, we have verified the adsorption potential of a novel covalent organic polymer for Au(iii), which provides a strong reference for the recycling of precious metal gold in secondary resources and the protection of environmental resources.

Covalent organic frameworks (COFs), as a new type of porous crystalline materials, are suitable for selective adsorption and separation of various heavy metal ions due to their stable framework structure,...

Due to a high operating voltage and theoretical capacity, P2-type layered Mn-based metal oxides are considered to be promising cathodes in sodium-ion batteries, but their poor structural stability in the process of Na⁺ insertion/deinsertion severely hinders their practical application. Here, an interesting K⁺ pre-intercalation is used to expand the interlayer distance and enhance the electrochemical reversibility of KsFexAlyMnzO2. With a suitable K⁺ content, the optimized electrode shows a high specific capacity of 135 mAh g⁻¹ at 0.1 C, a good rate capability of 80 mAh g⁻¹ at 5 C and an excellent cycling performance of 76.4% capacity retention after 200 cycles at a high rate of 5 C. This work proves the feasibility of a K⁺ pre-intercalation strategy in a P2-type layered cathode.

The second recovery of gold has fundamental environmental and economic significance. In this study, an enaminone covalent organic polymer (COP) was synthesized and used to recover gold from secondary resources. The ketene covalent organic polymer (COP) possessed good gold adsorption performance, and the best adsorption capacity could reach up to 1945 mg g-1 at 298 K, which was superior to traditional adsorbents. Meanwhile, the synthesized COP exhibited excellent adsorption selectivity and renewability of Au3+. The pseudo-second-order kinetic equation and Langmuir equation were suggested for describing the adsorption process. Moreover, this gold adsorption behavior was intended to be a spontaneous, endothermic, and entropy increasing process.

A copper-catalyzed [4+1] cycloannulation of 2-aminochalcones with ethyl 2-diazo-2-phenylacetate has been developed in this paper, along with migration of ester group, which provided a simple and effective method for the...

Thermally stable and well‐defined hydrocarbon polymers prepared via anionic alternating copolymerization of 1,3‐pentadiene (P monomer: trans (TP) and cis (CP) mixture) and styrene derivatives (S monomer: styrene (St) and 1,1‐diphenylethylene (DPE)) and subsequent hydrogenation and cationic cyclization modifications are reported. The TP/S/CP terpolymerization reveals that an incorporation of S‐alt‐CP sequence into the alternating chain is more favorable, while the S‐alt‐TP insertion is also possible especially under high temperature owing to their competitive energy barriers and thermodynamic properties. Then the resultant copolymers with equimolar amount of the two monomers and predominant linear units are intramolecularly cyclized with CF3SO3H, or hydrogenated with p‐toluenesulfonyl hydrazide, to afford soluble and thermally stable hydrocarbon polymers with controlled Mns and narrow ĐMs. The Tg of cylized polymer increases dramatically (ΔTg > 100 °C) on cyclization between the adjacent CC bond in the P structure and the aromatic ring of S unit through the intramolecular Friedel–Crafts alkylation. On the other hand, the Tg of hydrogenated product slightly decreases (ΔTg ≈ 10 °C) after 98% hydrogenation due to the increasing flexibility of the saturated main‐chain, while the Td increases about 60 °C due to the loss of CC bonds under oxygen atmosphere. A simple but practical method for synthesizing the thermally stable and well‐defined hydrocarbon polymers prepared via anionic alternating copolymerization of 1,3‐pentadiene (P monomer: trans and cis mixture) and styrene derivatives (S monomer: styrene (St) and 1,1‐diphenylethylene (DPE)) and followed by hydrogenation and cationic cyclization modifications.

Catalytic activities of Zn-promoted Hβ zeolite for gas-phase aza-heterocyclic-aromatization of acrolein dimethyl acetal and aniline to quinolines were investigated. the Zn/Hβ catalyst showed better selectivity to quinoline than the parent Hβ one. Characterization results demonstrated that the Zn/Hβ catalyst prepared via deposition precipitation method existed the isolated Zn²⁺ cations as well as the highly dispersed ZnO clusters, which not only decreased concentration of strong acid sites but also enhanced enhance aromatization process. As a result, the decrease of strong acid sites restrained the cracking of acrolein to acetaldehyde as well as the alkylation of quinoline to ethylquinoline effectively; and the Zn species of catalyst further improved aromatization process of dihydroquinoline to quinoline. Moreover, the Zn/Hβ catalyst presented relatively enhanced ability of anti-activation and excellent regenerability, owing to decrease strong acid-induced polymerization of active intermediates to form the coking. Under the optimized operating conditions, more than 51 % yield of quinoline was achieved over Zn/Hβ catalyst; which far exceeded quinoline yield (28 %) over the pure Hβ one. Besides, a plausible reaction routes in vapor-phase acrolein diethyl acetal with aniline to quinolines were suggested in this paper.