Fabrication of a ZnO Hexagonal Plates/rGO Composite for Application in Nitrite Sensing and Photocatalytic Hydrogen Production

Abstract

Recently, design and fabrication of electrochemical sensors have received huge attention because of their high sensitivity, cost-effectiveness, good selectivity, simple processing, and low detection limit. Herein, we have fabricated zinc oxide (ZnO) hexagonal plates/reduced graphene oxide (rGO) composite under benign approach. Different characterization techniques and approaches such as XRD, SEM, EDX, UV-vis, and XPS were utilized to authenticate the formation and phase purity of ZnO/rGO composite. Further, we have modified active surface area (3 mm) of bare glassy carbon electrode using ZnO/rGO as electro-catalyst (electrode material) for the construction of nitrite sensor. This modified electrode (ZnO/rGO/GCE) demonstrated low-limit of detection (DL) of 0.1 μM with good sensitivity of 2.47 μA/μMcm2. Moreover, fabricated ZnO/rGO/GCE exhibited excellent selectivity, stability and repeatability towards the detection of nitrite. Additionally, ZnO/rGO was also applied as photo-catalyst towards photo-catalytic hydrogen (H2) generation. The ZnO/rGO showed good H2 generation rate of 650.3 μmolg−1h−1 compared to the pristine rGO or ZnO.