Based On Palladium Metal Nanometer Materials Without Enzyme Sensor And Its Application

The development of metal nanoparticles has been making a greatprogress, which is currently regarded as the new generation of industrialrevolution in the field of metal materials, and thus has attracted manyresearchers’ attention in the scientific, social and application fields.Compared with the corresponding bulk materials, metal nanoparticlespossess of many attractive properties, such as large surface area, highsurface reactivity, and strong adsorption ability, which makes it widelyused as electrical, catalytic, magnetic and photo-catalytic materials invarious applications. It is well agreed that chemical/electrochemicalsensor is one of the most promising application for metal nanoparticles,while the research and development of metal nanoparticles is wellaligned with the development direction of sensor miniaturization.Currently, non-enzymatic electrochemical sensor based on metalnanomaterials has caused more and more attention and become oneof the hot topics in electroanalytical chemistry. People have recentlyshifted the sensor focus from using single type of metal nanomaterials tousing metal nanoparticles-based nanocomposites, which is mainlybecause the nanocomposites may bring the advantage of combiningmulti reactive properties and/or functional properties from multi metalnanoparticles and/or functional polymers and metal oxides and thuspromote the detection performance of electrochemical sensors.Palladium (Pd) as one of the novel metal materials has shown the highcatalytic activity, while Pd nanoparticles has been extensively used inthe areas of gas/chemical sensors, diverse catalysis and organicsynthesis etc.. However, due to the novelty and scarcity of Pd materials,a plenty of efforts have been spent to reduce the loading of Pdmaterials while keeping its high catalytic performance. A typicalexample is that Pd alloy materials, with much small amount of Pd, have been proved to be a good example with higher activity toward somesmall organic molecules. The motivation of this study is to develop thenon-enzymatic electrochemical sensor constructed with minimalloading of Pd nanomaterials, while keeping the high electrocatlyticproperties toward the detection of hydrogen peroxide, dopamine andascorbic acid. Multi-wall carbon nanotubes and metal oxides havebeen used to construct the Pd nanoparticles based nanocompositesfor electrochemical sensing application.1Electrocatalytic reduction of hydrogen peroxide on palladiumnanoparticles modified electrodePalladium nanoparticles were electrochemically deposited ontomulti-walled carbon nanotube (MWCNTs) modified electrode throughpotential step method. The synergic effect of palladium nanoparticlesand MWCNTs well contributed to the excellent electrochemicalresponse towards the electrochemical reduction of hydrogen peroxide.The results showed that the as-prepared electrode possessed of highstability, good reproducibility and high selectivity for theelectrochemical reduction of hydrogen peroxide. The as-developedmethod has been employed to determine H2O2concentration indisinfectant sample.2Selective and simultaneous detection of dopamine andascorbic acid using bimetallic Pd–Cu modified electrodePalladium and copper bimetallic nanoparticles have beensuccessfully loaded onto the multi-walled carbon nanotubes modifiedglassy carbon electrode using electrochemical deposition method.Electrochemical behaviors of DA and AA on the surface of the electrode were studied. The Pd–Cu alloy modified electrode obtainedin the Pd: Cu=1:2solution showed good performance for thesimultaneous detection of DA and AA. The linear range for DA and AArespectively were8.0×10-7-9.2×10-5M and4.0×10-5-1.1×10-3M. Thedetection limits for these two molecules were3.0×10-7M and1.1×10-5M (S/N=3), respectively.3Layer-by-layer construction of multi-walled carbon nanotubes,manganese oxide and palladium nanoparticles integrated compositeelectrode for hydrogen peroxide detectionWe have successfully fabricated an electrochemical hydrogenperoxide sensor based on the electrodeposition of Pd nanoparticlesand MnO2thin film onto MWCNTs modified GC electrode by cyclicvoltammetry. The prior electrodeposition of manganese oxide onto thecarbon nanotube surface helps achieved the deposition of moreuniform palladium nanoparticles on the electrode surface. Thesynergistic effect of high reactivity, electron promotor, and highconductivity of Pd, MnO2and MWCNTs has greatly increased theelectrochemical response and reduced the overpotential towards theelectrochemical oxidation of hydrogen peroxide. The as-preparedelectrode possessed high stability, good reproducibility, low detectionlimit and wide linear range, and has been used for the detection ofhydrogen peroxide in disinfectant sample.