Surface properties and electrochemical performance of nanostructured gold coatings electrodeposited on Au/SPCE for glucose detection / Mohammad Hafizudden Mohd Zaki

Screen-printed carbon electrode (SPCE) has been extensively employed as a matrix for sensing application. However, the SPCE still has a poor electrochemical activity to be used as a sensing electrode due to its lower conductivity and electrochemical properties than gold. Therefore, in this study, surface modification of SPCE with gold nanostructures coating and their respective electrochemical application as a nonenzymatic sensor for detection of glucose was investigated. Prior to gold nanostructures coating, SPCE was pre-treated by cleaning with H2SO4 followed by coating with a gold underlayer (Au/SPCE) to enhance the adhesion of the nanostructured gold coating to the SPCE surface. Two synthesis strategies were used to produce high surface area of gold coatings where first strategy involved the deposition of nanostructured gold using a hydrogen bubbles dynamic template and the second strategy was through dealloying of gold-copper alloy. The deposition parameters such as deposition potentials, deposition time of gold, the molar ratio of alloy electrolytes and also immersion time of the chemical dealloying were optimized to produce gold-based coatings. The modified SPCEs were characterized for their surface morphology, elemental composition, crystallite structures and surface roughness by FESEM, EDX, XRD and AFM, respectively, and their electrochemical and electrocatalytic properties by CV and EIS. The electrochemical performance of the gold electrode for glucose detection was analyzed by CV and CA in 0.1 M NaOH solution.