摘要
According to the Rourke＇s model, graphene oxide（GO） synthesized from the oxidation of graphite actual- ly consisted of partly oxidized graphene sheets and highly oxidized debris（OD）. The OD was strongly adhered to the surface of graphene sheets, while they could be facilely removed by a base-washing procedure. The existence and removal by base-washing of OD were characterized by means of thermogravimetric analysis（TGA）, FTIR spectros- copy, X-ray photoelectron spectroscopy（XPS）, transmission electron microscopy（TEM） and Raman spectroscopy. The adsorption of O13 not only made a great difference to the physical and chemical properties of GO, but also af- fected its electrochemical behavior when it was employed as an electrode material. In this article, we demonstrated that the electrochemical deposition and the subsequent voltammetric stripping analysis of mercury were significantly influenced by the presence of OD. The conseqnence suggests that the presence of OD on the sheets of GO restricts the electrochemical deposition behavior of mercury and further lowers the sensitivity of the voltammetric stripping responses. The sensitivity was observed as 0.78A·L·mo1^-1 at base-washed（bw）-GO/GC（glassy carbon） better than that at as-prepared GO（a-GO）/GC for 0.28 A·L·mo1^-1. The limit of detection was calculated as 2.95 and 0.83 μmol/L before and after removing the OD, respectively. The availability of both electrodes was evaluated by detecting Hg^2＋ in lake water specimens using standard samples recovery.
According to the Rourke＇s model, graphene oxide（GO） synthesized from the oxidation of graphite actual- ly consisted of partly oxidized graphene sheets and highly oxidized debris（OD）. The OD was strongly adhered to the surface of graphene sheets, while they could be facilely removed by a base-washing procedure. The existence and removal by base-washing of OD were characterized by means of thermogravimetric analysis（TGA）, FTIR spectros- copy, X-ray photoelectron spectroscopy（XPS）, transmission electron microscopy（TEM） and Raman spectroscopy. The adsorption of O13 not only made a great difference to the physical and chemical properties of GO, but also af- fected its electrochemical behavior when it was employed as an electrode material. In this article, we demonstrated that the electrochemical deposition and the subsequent voltammetric stripping analysis of mercury were significantly influenced by the presence of OD. The conseqnence suggests that the presence of OD on the sheets of GO restricts the electrochemical deposition behavior of mercury and further lowers the sensitivity of the voltammetric stripping responses. The sensitivity was observed as 0.78A·L·mo1^-1 at base-washed（bw）-GO/GC（glassy carbon） better than that at as-prepared GO（a-GO）/GC for 0.28 A·L·mo1^-1. The limit of detection was calculated as 2.95 and 0.83 μmol/L before and after removing the OD, respectively. The availability of both electrodes was evaluated by detecting Hg^2＋ in lake water specimens using standard samples recovery.
