钴氮原位共掺杂SiO_2@C修饰电极同时检测邻苯二酚和对苯二酚

Cobalt and Nitrogen in Situ Co-Doped SiO_2@C for Simultaneous Detection of Catechol and Hydroquinone

本文利用多巴胺易聚合、易还原和较强金属配位能力的特性,制备了聚多巴胺(PDA)包覆SiO_2,表面键合Co2+,在氮气氛围条件下,于800℃煅烧制备钴氮原位共掺杂SiO_2@C(SiO_2@C/N-Co)复合材料。分别应用扫描电镜、透射电镜、电化学方法对该材料进行结构和电化学性能表征。与氮掺杂SiO_2@C相比,钴掺杂后检测100μmol/L邻苯二酚(CC)和对苯二酚(HQ),其氧化峰电流值分别由-39.17μA和-24.0μA增加到-119.4μA和-110.8μA,即分别提高3.05和4.62倍。SiO_2@C/N-Co修饰电极可同时检测CC和HQ,其检出限分别为0.17、0.09μmol/L,线性范围分别为1.0~200μmol/L、0.5~400μmol/L。应用该方法检测九龙江水,对CC和HQ的回收率范围为96%~101.5%,相对标准偏差小于5%。

Polydopamine was used simultaneously as nitrogen-doped carbon precursors, adsorbent and reducing agent of COC12. Nitrogen and Co nanoparticles could be in situ doped and surface modified successively into/onto SiO2 @C spheres, i. e. , SiO2 @C/N-Co, via a facile and one-step calcination under nitrogen protection. The conductivity, electron transfer ability, and electrocatalytic activity of SiO2 @C sphere were improved by the synergistic effect of surface modification with Co nanoparticles and nitrogen doping. The sensitivity of this electrochemical sensor was enhanced. Compared with SiO2 @ C/N, the oxidation peak current of SiO2 @C/N-Co was increased from --39.17 A to --119.4 μA for 100 μmol/L of catechol （CC） and from --24.0 μA to --110.8 μA for 100 μmol/L of hydroquinone（HQ）. The sensitivity of SiO2@C/N-Co was improved 3.05 and 4.62 times for CC and HQ,respectively. Both CC and HQ could be detected simultaneously by SiO2 @ C/N-Co modified electrode with differential pulse voltammetry. With wide linear range（1.0-200 and 0.5-400μmol/L for CC and HQ,respectively） and low detection limit （0. 17 and 0. 09 μmol/L for CC and HQ, respectively）, this proposed method was successfully applied for simultaneous detection of CC and HQ in Jiulong River water.