Investigation of nickel slag waste as a modifier on graphene-TiO₂ microstructure for sensing phenolic compound

In the present work, the potential of nickel slag waste (NSW) was performed as a modifier of graphene-TiO₂ material for sensing phenolic compound under an electrochemical system. It was provided to produce variations of mineral components to improve electrochemical sensing in its application for a sensor device. Preparation of composite material (slag-graphene-TiO₂) was prepared through solid-state reaction by mixing of NSW, graphene, and TiO₂ anatase crystal. Based on these results, we discover the composition of NSW with various mineral contents and produced anatase TiO₂ crystal prepared via thermal method at 500 °C for 3 h. Subsequently, the slag-G-TiO₂ composite has been homogeneous and characterized using SEM–EDX shows the microstructure formed with the variation of elements content. Moreover, the electrochemical test for sensing phenol compound exhibits the exceptionally sensitivity towards phenol detection in electrolyte solution by the limit of detection (LoD) is 0.0367 ppm and % RSD value of 0.016%. The electrode also produce excellent stability properties by repeatability of 1 to 21 times and the average of oxidation current at 183.57 µA. Finally, we test with a real sample to obtain the ability of phenol detection.