Controllable synthesized diamond/CNWs film as a novel nanocarbon electrode with wide potential window and enhanced S/B ratio for electrochemical sensing

Abstract Ultra-low background current and wide potential window are simultaneously achieved on the diamond/carbon nanowalls (D/CNWs) films albeit with high sp2-C content. The morphology and composition of D/CNWs consisting of diamond nanoplatelets and vertically aligned CNWs are mainly modulated by changing the ratio of methane to hydrogen during deposition. D/CNWs electrodes exhibit controllable electrochemical properties related to various microstructures and sp2/sp3-C ratios. Impressively, it is unusual that the background of a series of D/CNWs is extremely low at the range of 2.34–3.56 μF/cm2. And the potential window remains wide from 2.45 to 2.72 V. The existence of the sp3-C, low C O content and hydrophobic surface of D/CNWs are beneficial to above electrochemical behaviors. Moreover, abundant graphene edges of D/CNWs guarantee good electrochemical activity. Finally, D/CNWs-3% electrode with thinner graphene layers was successfully applied in the simultaneous detection of Cd(II) and Pb(II) as low as 10 µg L−1 (practical limit of detection). D/CNWs-3% electrode exhibits enhanced signal to background (S/B) ratio compared to graphite and boron-doped diamond electrode. The simultaneous determination also confirms wide linear range of D/CNWs-3% from 10 to 1000 µg L−1. Hence, D/CNWs electrode with outstanding electrochemical properties is promising for electrochemical sensing.