电活性石墨烯凝胶材料的构筑及传感性能研究

发布时间：2019-04-26 09:02

【摘要】：石墨烯具备优异的电学、光学、物理化学等特性,然而,由于层间作用力的影响,导致现有的石墨烯材料比表面积小、导电性低,固有优越性质未能充分体现。凝胶化方法是破解上述问题的有效策略,近年,石墨烯凝胶在传感、催化和能源等领域得到广泛应用,但目前构筑的石墨烯凝胶往往大而空,性能并不理想,进一步提高其电子传导性是亟待解决的问题。此外,石墨烯凝胶不具备特殊的催化活性以及功能性,因此,对其进行功能化具有重要意义。于此,我们通过构筑氮硫共掺杂多重石墨烯气凝胶,并复合硫化镍钴、核壳型钯金纳米粒子,实现了石墨烯凝胶材料在电子传导性、电解质传输速率和催化活性等方面的显著提升和功能化,拓展其在传感领域中的应用。构筑氮硫共掺杂多重石墨烯凝胶以提高材料电子传导率和电解质亲和力。以氧化石墨为原料,硫脲、对苯二胺为氮源和硫源,水热还原制备单重石墨烯气凝胶;而后置于与之大小相契合的容器中,在凝胶上方刺孔以打通内部封闭孔,并从孔道中引入氧化石墨烯的混合分散液,继续凝胶化反应获得二重气凝胶;重复上述过程,构筑多重石墨烯气凝胶;以磷酸进行活化,最后在Ar/H_2氛围中热处理得到氮硫共掺杂多重石墨烯凝胶(N,S-MGA-n)。该凝胶呈现独特三维网络多孔结构,比表面积高达1106.8 m~2/g,展示出比普通石墨烯凝胶更高密度、导电性和电化学活性,且电化学特性能通过改变凝胶化次数进行调控。制备Ni Co_2S_4/N,S-MGA复合材料并采用电容为模型研究材料电化学性能。以叔丁醇为“软模板”,在N,S-MGA内部原位生长Ni Co LDH,经硫化钠硫化后得Ni Co_2S_4/N,S-MGA-5复合材料;其比表面积为76.3 m~2g~(-1),比电容达822.5 F/g(1A/g下),电流密度增至60 A/g后,电容仍达244.4 F/g;两电极体系中能量密度达122 Wh/kg(P为800 W/kg),在连续循环充放电3000次后,比电容量衰减不到0.62%。数据结果表明Ni Co_2S_4/N,S-MGA具备极高电活性、电子传导性和优异的电化学稳定性。研究Ni Co_2S_4/N,S-MGA复合材料对葡萄糖的催化作用并构建生物传感器。以Ni Co_2S_4/N,S-MGA为传感材料、葡萄糖氧化酶充当识别因子,构建葡萄糖生物传感器;该传感器对葡萄糖展示出良好的电化学响应,浓度线性范围为1.0×10~(-5)~1.5×10~(-3 )M,检测限为3.0×10~(-6 )M,这得益于复合材料良好的电解质亲和力、电子传导性和电催化活性。方法重现性和稳定性好,成功应用于实际样品中葡萄糖的测定。合成Pd@Au/N,S-MGA复合材料并应用于多巴胺的检测。制备规整的Pd纳米立方体,以之为“核”合成Pd@Au纳米多面体,再与N,S-MGA-5复合并构建多巴胺传感器。其线性响应范围为1.0×10~(-9)~4.0×10~(-5) M,检测限为3.6×10~(-10) M(S/N=3),超灵敏的电化学响应归功于Pd@Au优异电催化活性和复合材料间的电化学协同效应。方法重现性、稳定性好,抗干扰性强,成功用于实际样品中多巴胺的测定,回收率为96.0%~100.9%。
[Abstract]:Graphene has excellent electrical, optical, physical and chemical properties. However, due to the influence of interlayer forces, the existing graphene materials have small specific surface area and low conductivity, and their inherent superior properties have not been fully reflected. Gelation is an effective strategy to solve these problems. In recent years, graphene gels have been widely used in the fields of sensing, catalysis and energy, but the graphene gels constructed at present are often large and empty, and their properties are not ideal. The further improvement of its electronic conductivity is an urgent problem to be solved. In addition, graphene gel has no special catalytic activity and function, so it is of great significance to functionalize it. By constructing N-S co-doped multiple graphene aerogels and Ni-Co sulphide and core-shell palladium-gold nanoparticles, we have realized the electronic conductivity of graphene gel materials. The electrolyte transport rate and catalytic activity have been greatly improved and functionalized, and their applications in sensing field have been expanded. Nitrogen-sulfur co-doped graphene gels were constructed to improve the electronic conductivity and electrolyte affinity of the materials. Using graphite oxide as raw material, thiourea and p-phenylenediamine as nitrogen and sulfur sources, single graphene aerogel was prepared by hydrothermal reduction. Then it is placed in a container which fits the size of the gel, piercing the hole above the gel to open the internal sealing hole, and introducing the mixed dispersion solution of graphene oxide from the pore channel to continue the gelation reaction to obtain the double aerogel. The polygraphene aerogel was prepared by repeating the above process, activated by phosphoric acid, and heat treated in Ar/H_2 atmosphere to obtain N, S co-doped poly-graphene gel (N, S _ (x) MGA _ (a) 路n ~ (- 1). The gel exhibits a unique three-dimensional network porous structure with a specific surface area of 1106.8 mg / 2 g, showing higher density, conductivity and electrochemical activity than the normal graphene gel. The electrochemical properties of the gel are regulated by changing the gelation times. The electrochemical properties of Ni Co_2S_4/N,S-MGA composites were studied by capacitance model. Using tert-butanol as "soft template", Ni Co_2S_4/N,S-MGA-5 composites were prepared by in-situ growth of Ni Co LDH, in-situ in the presence of sodium sulfide. The specific surface area is 76.3m 路2g ~ (- 1), the specific capacitance is 822.5 F 路g ~ (- 1), the current density is 60 A 路g ~ (- 1), the capacitance is 244.4 F 路g ~ (- 1), and the specific capacitance is 822.5 F 路g ~ (- 1). The energy density of the two-electrode system is 122 Wh/kg (P = 800 W/kg). After 3000 cycles of charge and discharge, the specific capacitance decreases less than 0.62%. The results show that Ni Co_2S_4/N,S-MGA has very high electrical activity, electronic conductivity and excellent electrochemical stability. The catalytic effect of Ni Co_2S_4/N,S-MGA composite on glucose was studied and the biosensor was constructed. Glucose biosensor was constructed by using Ni Co_2S_4/N,S-MGA as sensing material and glucose oxidase as recognition factor. The sensor showed a good electrochemical response to glucose. The linear range of the sensor was 1.0 脳 10 ~ (- 5) ~ 1.5 脳 10 ~ (- 3) M, and the detection limit was 3.0 脳 10 ~ (- 6) M, which was due to the good electrolyte affinity of the composite, and the linear range was 1.0 脳 10 ~ (- 5) ~ 1.5 脳 10 ~ (- 3) M. Electronic conductivity and electrocatalytic activity. The method has good reproducibility and stability and has been successfully applied to the determination of glucose in practical samples. Pd@Au/N,S-MGA composite was synthesized and applied to the detection of dopamine. The regular Pd nano-cube was prepared and used as "nucleus" to synthesize Pd@Au nano-polyhedron. Then, the Pd@Au nano-polyhedron was combined with N, S-MGA-O-5 and the dopamine sensor was constructed. The linear response range is 1.0 脳 10 ~ (- 9) ~ 4.0 脳 10 ~ (- 5) M, and the detection limit is 3.6 脳 10 ~ (- 10) M (S/N=3. The ultra-sensitive electrochemical response is attributed to the excellent electrocatalytic activity of Pd@Au and the electrochemical synergistic effect between composites. The method has the advantages of good reproducibility, good stability and strong anti-interference. The method has been successfully applied to the determination of dopamine in practical samples with a recovery of 96.0% and 100.9%.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ427.26;TP212

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