| 4-Chlorophenol is a kind of organic pollutant with highly toxic to environment, owing to a low concentration and stable structure. Detection of 4-chlorophenol is an important research topic. Electrochemical detection technology has an advantage in the detection of 4-chlorophenol due to its rapid, sensitive, and efficient characteristics. In this paper, a series of single metal/graphene and bimetal/graphene materials were prepared and fully characterized. And glass carbon electrodes modified with these prepared materials were constructed and applied for the detection of 4-chlorophenol in water.An improved method was used to prepare graphene oxide. Then three monometal/graphene materials including Cu/graphene, Pd/graphene, Au/graphene were synthesized by one-step chemical reduction. Two bimetal/graphene materials including Cu-Pd/graphene and Cu-Au/graphene were prepared by two-step chemical reduction. Cyclic voltammetry results showed that the best test conditions were 100 mV/s of sweep speed, pH 6.5 in phosphate buffer. By using Specific surface area, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and electrochemical impedance these methods, mental elements relative concentration, chemical composition, valence spectral line and structure in the five kinds of prepared metals/graphene materials were characterized. The results showed that the specific surface area of the prepared catalysts were 300?460 m2/g, which the specific surce of Cu-Pd/graphene, Cu-Au/graphene, Cu/graphene, Pd/graphene, Au/graphene reached 386.036 m2/g,456.339 m2/g,302.706 m2/g,320.539 m2/g,362.738 m2/g, respectively. The specific surface area of Cu-Pd/graphene and Cu-Au/graphene reached 386.036 m2/g and 456.339 m2/g, respectively, which were larger than that of monometal/graphene materials. The metal particles in graphene were distributed evenly. The size of particles was between 5?10 nm without obvious agglomeration,which Cu/graphene was 7.89±0.30 nm, Pd/graphene was 7.27±0.28 nm, Au/graphene was 7.33±0.27 nm, Cu-Pd/graphene was 6.96±0.30 nm, Cu-Au/graphene was 6.92±0.30 nm. Electrochemical impedance spectroscopy showed the resistance of Cu-Au/graphene was a minimum of 205 ?, the followed were Au/graphene, Pd-Cu/graphene, Pd/graphene, Cu/graphene.A series of glass carbon electrods(GCE) modified with prepared metal/graphene materials were parepared and used to detect 4-Chlorophenol in water. Cyclic voltammetry test results showed that -0.9-0.9 V of voltage,100 mV/s of sweep speed, pH 6.5 of phosphate buffer were the best test conditions. These modified electrodes had good electrochemical responses to 4-chlorophenol. The linear range of Pd/graphene/GCE was 1?100 ?mol/L, and the detection limit was 0.34 ?mol/L (S/N=3). The linear range of Au/graphene/GCE was 0.5?80 ?mol/L, the detection limit was 0.17 ?mol/L (S/N=3). Compared with the detection results of monometal/graphene/GCE, Cu-Pd/graphene/GCE and Cu-Au/graphene/GCE had lower detection limits and broader linear ranges. Au-Cu/graphene/GCE had the lowest detection limit 0.10 mol/L and the linear range was 0.5-85 mol/L, which showed that the catalyst prepared in this experiment has good catalytic characteristics for 4-chlorophenols. It indicates that prepared metal/graphene electrodes show good potential application in the electrochemistry detection of 4-chlorophenol. |
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