Preparation And Electrochemical Investigation Of PdAgCo And AgCo Alloy Electroactyst

The excessive consumption of fossil fuel and the lack of natural resources make it extremely urgent to develop sustainable energy. Though Li-battery occupies the most share of the market, there are still many technical problems to be resolved. While the fuel cells only need to fill the fuel regularly and it can convert the chemical energy directly to electricity. And it can also provide energy continuously at a high conversion rate without any pollution, which is an ideal way of energy conversion. As is well known that catalyst is the key to the proton exchange membrane fuel cells (PEMFCs). But the content of precious metal Pt and Pd are aways high in the main catalysts, which is a great limition to the development and application of the fuel cells. Hence,regarding the high catalytic and low cost catalyst as a goal, we prepared high catalytic and low cost Co-doped PdAgCo and AgCo nanoparticles.Firstly, we text the cyclic voltammograms by electrochemical workstation,then we also test the performance of direct formic acid oxidation (FAO)of PdAgCo and AgCo. Through the transmission electron microscopy(TEM), high power electron microscopy (HRTEM), X-ray diffraction(XRD) we characterized and analyzed the phase, morphology, structure and components of these two catalysts,(1) This paper synthesized monodisperse PdAgCo and PdAg nanoparticles by adding the surface of reducing agent oil amine (OA) to the reaction system. Under the transmission electron microscopy (TEM)as you can see, the diameter size of PdAg nanoparticles are about 6 nm and they are uniform spherical particles, the diameter size of PdAgCo nanoparticles are about 8 nm and the particles size is relatively uniform.The data of XRD show that PdAg nanoparticles mainly exist in the form of plane ( 11). Though only a little bit Co doped into PdAgCo nanoparticles, they are also the ternary metal. Our results show that the catalytic activity of PdAgCo/C (1133.249 mA/mgPd) for formic acid oxidation (FAO) is approximately 2.4 times larger than the commercial Pd/C (483.563 mA/mgPd) and 1.7 times larger than the PdAg/C (680.741 mA/mgPd). This study indicates that as some Co element dope in PdAg bimetallic NPs the FAO activity can be improved significantly. The oleylamine is a kind of long chain organic reductant in this experiment,it's not only control the morphology of PdAgCo and PdAg nanoparticles,but also have the effect of end capping agent.(2) In the organic oleylamine, we prepared a series of AgCo with different calcination temperature and different support to compare their electric catalytic. The XRD data indicate that the prepared catalysts are Face-centered cubic (fcc). Electrochemical tests show that changing the support for ZIF-8 at the best calcination temperature 550?, we can get AgCo/ZIF-8-550? whose electrochemical activity is better than AgCo/C at the same temperature.(3) Combining the guidance of the theoretical calculation with the experiments, we obtained the best catalytic performance of AgCo catalysts by controlling the speed of calcination temperature. We calcined the AgCo/ZIF-8 nanoparticles catalyst at the speed of 5?/min?8?/min and 10 ? /min, separately. The results show that the synthesed AgCo/ZIF-8-550? which is calcined at the speed of 8?/min has the better ORR activity and stability.