水熱法/溶劑熱法合成二硒化鎢應用於電容去離子技術

Hydrothermal/Solvothermal Synthesis of Tungsten Diselenide (WSe2) For Capacitive Deionization

董明叡(Ming-Ruel Dong)

指導教授 ： 彭晴玉

共同指導教授 ： 許世杰

淡江大學/工學院/水資源及環境工程學系碩士班/碩士(2019年)

https://doi.org/10.6846/TKU.2019.00655

摘要

過渡金屬硫化物(Transition metal dichalcogenides, TMD)擁有非凡的電化學、光學和電催化性能，近年受到科學界矚目。作為TMD的關鍵成員之一，二硒化鎢(Tungsten Diselenide, WSe2) 具有1.2 eV的間接帶隙並且在單層中具有1.7 eV的直接帶隙、超低導熱率(0.05 W m-1 k-1)、邊緣位置提供更多活性位點等優勢；本研究之目的即以水熱法或溶劑熱法合成高質量少層數的WSe2，並應用WSe2於電容去離子系統。
電容去離子(Capacitive Deionization, CDI)是深具潛力的低能耗脫鹽技術，透過在兩個電極之間施加電壓從鹽水中去除離子。本研究以二硒化鎢以作為CDI的電極材料。WSe2表現出良好的循環穩定性，50 mg/L NaCl溶液，施加1.2 V電壓，鈉離子電吸附容量為1.8 mg Na+/g WSe2 (水熱合成法)與2.9 mg Na+/g WSe2 (溶劑熱合成法)。
本研究的另一個目的是製備WSe2/rGO複合材料，石墨烯可以提高WSe2的比電容值(116.6 F/g)。於50 mg / L NaCl溶液中，施加1.2 V，WSe2/rGO具有更高的鈉離子電吸附容量(3.1 mg Na+/g WSe2/rGO)。

關鍵字

水熱法 ； 溶劑熱法 ； 過渡金屬硫化物 ； 二硒化鎢 ； 電容去離子

並列摘要

Layered transition metal dichalcogenides (TMDs) have attracted much attention from the scientific community due to their extraordinary electrical, optical and electrocatalytic properties. As a key member of TMDs, WSe2 has indirect bandgap of 1.2 eV in bulk and direct one of 1.7 eV in monolayer, ultralow thermal conductivities (0.05W m-1 k-1), more exposed edges providing active sites. Therefore, the objective of this study is to synthesize high quality and few-layered WSe2 nanosheets by hydrothermal or solvothermal method and then apply it to the capacitive deionization system.
Capacitive deionization (CDI) is a promising technology for removal of ions from saline water upon applying a voltage between two electrodes. In this study, Tungsten Diselenide (WSe2) has been employed as electrode material for CDI. Tungsten Diselenide (WSe2) demonstrates a good cycling stability, high sodium electrosorption capacity of 1.8 mg Na+/g WSe2 (hydrothermal synthesized) and 2.9 mg Na+/g WSe2 (solvothermal synthesized) at 1.2 V applied voltage in 50 mg/L NaCl solution.
Another purpose of this study is to prepare WSe2/rGO composites, which can improve specific capacitance to 116.6 F/g by adding graphene. Higher sodium electrosorption capacity of 3.1 mg Na+/g WSe2/rGO was found with WSe2/rGO composites at 1.2 V applied voltage in 50 mg/L NaCl solution.

並列關鍵字

Capacitive Deionization ； Transition Metal Dichalcogenides ； Tungsten Diselenide (WSe2) ； Hydrothermal ； Solvothermal

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