Crumpled graphene oxide decorated SnO2 nanocolumns for the electrochemical detection of free chlorine

Abstract

A crumpled graphene oxide-SnO 2 nanocolumn (CGO-SnO 2 ) composite electrode was fabricated using aerosol-based techniques. First, SnO 2 nanocolumn thin films were fabricated using an aerosol chemical vapor deposition (ACVD) technique. The surface of the nanocolumn was then decorated with CGO by electrospray deposition. The CGOSnO 2 electrode was utilized for the electrochemical detection and determination of the free chlorine concentration in aqueous solutions using linear sweep voltammetry (LSV) and amperometric i-t curve techniques. The CGO-SnO 2 electrodes worked through the direct electrochemical reduction of hypochlorite ions (ClO -) on the surface of the electrode, which was used to determine the free chlorine concentration. The electrodes operate over a wide linear range of 0.1-10.08 ppm, with a sensitivity of 2.69 lA lM -1 cm -2 . Further, selectivity studies showed that these electrodes easily conquer the electrochemical signals of other common ions in drinking water distribution systems, and only shows the electrochemical reduction signals of free chlorine. Finally, the CGO-SnO 2 electrodes were successfully employed for the detection of free chlorine in tap water solutions (St. Louis, MO 63130, USA) with a sensitivity of 5.86 lA lM -1 cm -2 . Overall, the sensor fabricated using simple and scalable aerosol-based techniques showed a comparable performance to previous studies on amperometric chlorine sensing using carbonbased electrodes.

Electrospraying an enabling technology for pharmaceutical and biomedical applications: A review

“…A low cost conductometric sensor was fabricated by electrospray printing of graphene oxide (GO) flakes onto an IC chip for the detection of gas (ammonia) molecules and relative humidity (Taylor & Velasquez-Garcia, 2015). For the electrochemical detection of free chlorine in water, a crumpled graphene oxide - tin oxide (CGO-SnO 2 ) composite electrode was fabricated by ES of GO sheets on chemical vapor deposited SnO 2 nanocolumns (Soundappan, Haddad, Kavadiya, Raliya, & Biswas, 2017). A humidity sensor with linear responsivity and capability of recording relative humidity from 0 to 90% was fabricated as bi-layered thin films by ES exfoliated chromium carbide (Cr 3 C 2 ) flakes dispersed in polyacrylamide (PAM) (Kim, Sajid, Kim, Na, & Choi, 2017).…”

Detection of free chlorine in water using graphene-like carbon based chemiresistive sensors

“…Detection limits around 10 ppb are comfortably achievable, but all these methods require the use of fresh reagents for each sample point. Electrochemical methods are mainly based on amperometry, 4,32,33,[74][75][76] and linear sweep voltammetry. 30,77,78 They work reagent-less and can also achieve detection limits around 10 ppb, (3 ppb in the best case 33 ) but depend on maintenance-intensive reference electrodes.…”

Potentiometric Sensor Based on Carbon Paste Electrode for Monitoring Total Residual Chlorine in Electrolytically-Treated Ballast Water

“…Up to now, various analytical methods for determination of TRC, such as spectrophotometric methods [ 10 ], titration [ 11 ], chromatography coupled to mass spectrometry [ 12 ], chemiluminescence [ 13 , 14 ], and electrochemical methods [ 15 , 16 , 17 , 18 ], have been established. The spectrophotometric methods based on o-toluidine (DMB) [ 19 ] and N, N-diethyl-p-phenylenediamine (DPD) [ 20 , 21 ] and titration method are widely used for detection of TRC in water.…”