Ag-modified carbon fiber as a stable sensor

Abstract

Carbon Fiber (CF) electrode has a wide range of applications as an electric field sensor. However, its use is limited because of its poor stability. In this paper, the CF was pretreated by thermal oxidation (400 °C, 1 h) to remove surface impurities, resulting in 2.3% mass reduction, which means the increase of effective specific surface area. XRD and EDS confirmed the nano-silver coating was chemically modified on the surface of CF by electroplating. Charging current density differences and Tafel slope showed 6.19 mF cm−2 and 77 mV dec−1, respectively, which implied outstanding electrochemical performance. As a sensor, the Ag-modified CF electrode-pair has small potential difference drift of 29 μV/24 h and excellent response property to low frequency electric field signal, along with lower AC impedance (1.42 Ω@1 Hz) and electrochemical self-noise (1.38 nV/rt (Hz)@1 Hz). The novel Ag-modified CF electrodes provided a potential choice for the design of high-sensitivity marine electric field sensor.