Doped Carbon Materials Based On Nanodiamond And Boron Carbide As Non Platinum Electrocatalysts

With the development of society and the growth of global economic, the demand for energy is growing. Renewable hydrogen fuel cell used hydrogen as original material is constituted with water electrolysis system and fuel cell system. The oxygen electrode is an important restricting factor in both oxygen evolution reaction and oxygen reduction reaction. The high cost and short life of precious metals such as platinum and platinum alloy catalysts have hindered its further development. Therefore, the development and preparation of a high activity non-precious metal catalyst with low cost and good stability has become the key to solve this problem. In this article the non-platinum catalysts based on high stability of nanodiamonds and nano boron carbide have been prepared.In this study, a bifunctional catalyst with a nano diamond core, cobalt nitrogen co-doped graphite carbon layer shell(Co-N-C/ND) has been prepared. First, the nanodiamond was vacuum heated to obtain a graphitized layer shell to form C/ND, the cobalt particles was loaded on the surface of C/ND using a microwave glycol method. Then the material was washed and dried. The resulting material was mixed with melamine sufficiently, the obtained powder was heat treated at 600 ?C under the environment of N2 protection. The Co-N-C/ND has been prepared. The average electron transfer number between the potential of-0.4 V and-0.7 V is 3.82, the oxygen reduction reaction catalytic activity is close to commercial Pt/C. It also shows better catalytic activity for oxygen evolution reaction with a starting overpotential of 0.43 V and a current density of 3.19 mA cm-2 at 0.7 V. It shows better stability compared with the Co-N-C catalyst based on XC72 prepared in the same situation.A novel boron-nitrogen co-doped carbon material non-platinum catalyst(B-N-C/ B4C) based on nano boron carbide was prepared. The B4 C was mixed with cobalt using a microwave glycol method. The obtained powder was heat treated at 600 ?C under the environment of N2 protection. The B-N-C/ B4 C has been prepared. As a non-metal catalyst, it shows a good oxygen reduction reaction catalytic performance under alkaline conditions, the average electron transfer number between the potential of-0.4 V and-0.7 V is 3.82, the oxygen reduction reaction catalytic activity is close to commercial Pt/C. After cycling scaning under alkaline conditions, it exhibits excellent stability. After the same testing in acidic electrolyte, it also shows oxygen reduction reaction catalytic performance and an excellent stability.