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 similar to 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 x 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.

Automated summary

An amperometric sensor for the determination of Cr(VI) was fabricated using a titanium dioxide-reduced graphene oxide composite as the sensing element. The composite showed good responses to Cr(VI) in the concentration range of 50 to 500 ppb, with no signal interference from other ions present in the solution.