用于检测六价铬的二氧化钛-石墨烯复合电化学传感器

六价铬 (Cr(VI)) 化合物可用于各种行业，但具有毒性和致癌性。本文使用二氧化钛 (TiO-₂) -还原氧化石墨烯 (rGO) 复合材料作为传感元件，制造了一种用于测定 Cr(VI) 的电流传感器。该复合材料是按照溶胶?凝胶化学合成的，产生尺寸约为 50 nm 的 TiO₂ 纳米颗粒，固定在化学剥离的 rGO 片材上。该复合材料用于三电极电化学电池并以电流模式运行，对 50?500 ppb Cr(VI) 表现出良好的响应。对 pH 3 Mcilvane 缓冲介质的最佳结果显示灵敏度为 9.12 × 10?4 ppb?1，检测限为 6 ppb，200 ppm Ca(II)、150 ppm Mg(II) 和 50 ppb Pb(II) 没有信号干扰。TiO₂-rGO 传感器的优异结果可归因于TiO₂和 rGO 之间的协同效应，这是由于 n-p 异质结的存在和 rGO 上TiO₂ 纳米颗粒的形成。

Titanium dioxide-graphene composite electrochemical sensor for detection of hexavalent chromium

Hexavalent chromium (Cr(VI)) compound is useful to various industries but is toxic and carcinogenic. In this research work, we fabricate an amperometric sensor for the determination of Cr(VI), using a titanium dioxide (TiO2)-reduced graphene oxide (rGO) composite as the sensing element. The composite was synthesized following sol?gel chemistry, yielding TiO2 nanoparticles of ~50 nm in size, immobilized on chemically exfoliated rGO sheets. The composite was employed in a 3-electrode electrochemical cell and operated in an amperometric mode, exhibiting good responses to the 50 to 500 ppb Cr(VI). Our best result from pH 3 Mcilvane’s buffer medium reveals the sensitivity of 9.12 × 10?4 ppb?1 and a detection limit of 6 ppb with no signal interference from 200 ppm Ca(II), 150 ppm Mg(II), and 50 ppb Pb(II). The excellent results of the TiO2-rGO sensor can be attributed to synergic effects between TiO2 and rGO, resulting from the presence of n-p heterojunctions and the formation of the TiO2 nanoparticles on rGO.