scholarly journals Hypercrosslinked Ionic Polymers with High Ionic Content for Efficient Conversion of Carbon Dioxide into Cyclic Carbonates

Catalysts ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 62
Author(s):  
Xu Liao ◽  
Baoyou Pei ◽  
Ruixun Ma ◽  
Lingzheng Kong ◽  
Xilin Gao ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Reaction Times ◽  
Large Specific Surface Area ◽  
Cyclic Carbonates ◽  
Ionic Polymers ◽  
Ionic Content ◽  
Metal Free

The effective conversion of carbon dioxide (CO2) into cyclic carbonates requires porous materials with high ionic content and large specific surface area. Herein, we developed a new systematic post-synthetic modification strategy for synthesizing imidazolium-based hypercrosslinked ionic polymers (HIPs) with high ionic content (up to 2.1 mmol g−1) and large specific surface area (385 m2 g−1) from porous hypercrosslinked polymers (HCPs) through addition reaction and quaternization. The obtained HIPs were efficient in CO2 capture and conversion. Under the synergistic effect of high ionic content, large specific surface area, and plentiful micro/mesoporosity, the metal-free catalyst [HCP-CH2-Im][Cl]-1 exhibited quantitative selectivities, high catalytic yields, and good substrate compatibility for the conversion of CO2 into cyclic carbonates at atmospheric pressure (0.1 MPa) in a shorter reaction time in the absence of cocatalysts, solvents, and additives. High catalytic yields (styrene oxide, 120 °C, 8 h, 94% yield; 100 °C, 20 h, 93% yield) can be achieved by appropriately extending the reaction times at low temperature, and the reaction times are shorter than other porous materials under the same conditions. This work provides a new strategy for synthesizing an efficient metal-free heterogeneous catalyst with high ionic content and a large specific surface area from HCPs for the conversion of CO2 into cyclic carbonates. It also demonstrates that the ionic content and specific surface area must be coordinated to obtain high catalytic activity for CO2 cycloaddition reaction.

scholarly journals Nanocomposite Materials Based on Electrochemically Synthesized Graphene Polymers: Molecular Architecture Strategies for Sensor Applications

Chemosensors ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 149
Author(s):  
André Olean-Oliveira ◽  
Gilberto A. Oliveira Brito ◽  
Celso Xavier Cardoso ◽  
Marcos F. S. Teixeira
Keyword(s):  
Conducting Polymers ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Electrochemical Sensors ◽  
Structural Characteristics ◽  
Low Cost ◽  
Large Specific Surface Area ◽  
Molecular Architecture ◽  
Sensor Applications

The use of graphene and its derivatives in the development of electrochemical sensors has been growing in recent decades. Part of this success is due to the excellent characteristics of such materials, such as good electrical and mechanical properties and a large specific surface area. The formation of composites and nanocomposites with these two materials leads to better sensing performance compared to pure graphene and conductive polymers. The increased large specific surface area of the nanocomposites and the synergistic effect between graphene and conducting polymers is responsible for this interesting result. The most widely used methodologies for the synthesis of these materials are still based on chemical routes. However, electrochemical routes have emerged and are gaining space, affording advantages such as low cost and the promising possibility of modulation of the structural characteristics of composites. As a result, application in sensor devices can lead to increased sensitivity and decreased analysis cost. Thus, this review presents the main aspects for the construction of nanomaterials based on graphene oxide and conducting polymers, as well as the recent efforts made to apply this methodology in the development of sensors and biosensors.

Three-dimensional graphene encapsulated hollow CoSe2-SnSe2 nanoboxes for high performance asymmetric supercapacitors

2022 ◽  
Author(s):  
Kainan Li ◽  
Ke Zheng ◽  
Zhifang Zhang ◽  
Kuan Li ◽  
Ziyao Bian ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Active Sites ◽  
Specific Capacity ◽  
Three Dimensional ◽  
Hollow Structure ◽  
Large Specific Surface Area ◽  
Composite Aerogel

Abstract Construction of metal selenides with a large specific surface area and a hollow structure is one of the effective methods to improve the electrochemical performance of supercapacitors. However, the nano-material easily agglomerates due to the lack of support, resulting in the loss of electrochemical performance. Herein, we successfully design a three-dimensional graphene (3DG) encapsulation-protected hollow nanoboxes (CoSe2-SnSe2) composite aerogel (3DG/CoSe2-SnSe2) via a co-precipitation method coupled with self-assembly route, followed by a high temperature selenidation strategy. The obtained aerogel possesses porous 3DG conductive network, large specific surface area and plenty of reactive active sites. It could be used as a flexible and binder-free electrode after a facile mechanical compression process, which provided a high specific capacitance of 460 F g-1 at 0.5 A g-1, good rate capability of 212.7 F g-1 at 10 A g-1, and excellent cycle stability due to the fast electron/ion transfer and electrolyte diffusion. With the as-prepared 3DG/CoSe2-SnSe2 as positive electrodes and the AC (activated carbon) as negative electrodes, an asymmetric supercapacitor (3DG/CoSe2-SnSe2//AC) was fabricated, which delivered a high specific capacity of 38 F g-1 at 1A g-1 and an energy density of 11.89 W h kg-1 at 749.9 W kg-1, as well as a capacitance retention of 91.1% after 3000 cycles. This work provides a new method for preparing electrode material.

In-situ controlled synthesis of NiFe MOF materials with excellent electrocatalytic performances for water splitting

2021 ◽  
Vol 14 (02) ◽  
pp. 2151011
Author(s):  
Jingwen Jia ◽  
Longfu Wei ◽  
Ziting Guo ◽  
Fang Li ◽  
Changlin Yu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Water Splitting ◽  
Specific Surface Area ◽  
High Performance ◽  
Alkaline Condition ◽  
High Porosity ◽  
Large Specific Surface Area ◽  
Electrocatalytic Performance

Metal–organic frameworks (MOFs) are the electrocatalytic materials with large specific surface area, high porosity, controllable structure and monodisperse active center, which is a promising candidate for the application of electrochemical energy conversion. However, the electrocatalytic performance of pure MOFs is seriously limited its poor conductivity and stability. In this work, high-performance electrocatalyst was fabricated through combining NiFe/MOF on nickel foam (NF) via in-situ growth strategy. Through rational control of the time and ratio in reaction precursors, we realized the effective manipulation of the growth behavior, and further investigated the electrocatalytic performance in water splitting. The catalyst presented excellent electrocatalytic performance for water splitting, with low overpotential of 260 mV in alkaline condition at a current density of 50 mA[Formula: see text], which is benefited from the large specific surface area and active sites. This study demonstrates that the rational design of NiFe MOF/NF plays a significant role in high-performance electrocatalyst.

Safe disposal of radioactive iodide ions from solutions by Ag2O grafted sodium niobate nanofibers

2016 ◽  
Vol 45 (2) ◽  
pp. 753-759 ◽  
Author(s):  
Wanjun Mu ◽  
Xingliang Li ◽  
Guoping Liu ◽  
Qianhong Yu ◽  
Xiang Xie ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Radioactive Iodine ◽  
Large Specific Surface Area ◽  
Sodium Niobate ◽  
Safe Disposal ◽  
Iodide Ions

To capture radioactive iodine from wastewater, Ag2O particles are anchored firmly onto Nb2Na2O6·H2O nanofibers with a large specific surface area that allows them to disperse sufficiently without forming aggregates.

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