Based On The Preparation Of Coordination Complexes Electrocatalyst And Its Electrochemical Property For OER/ORR

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are the core reaction of many energy storage and conversion systems. The development and preparation of highly efficient and low-cost electrocatalysts of OER and ORR for energy storage and conversion systems play a vital role in commercialization. In this work, we prepared coordination complexes and the derivants of coordination complexes electrocatalysts. We mainly used XRD, XPS, FT-IR, TEM, N2 adsorption-desorption, TG, Raman to characterize the structure of the electrocatalysts, and studied the ORR and OER performance of the electrocatalysts in the alkaline electrolyte.The MIL-101(Cr) catalysts were prepared by a hydro thermal method, and then the Co-Fe/MIL-101(Cr) catalysts were prepared by a impregnation process with different molar ratio of Co and Fe. The Co-Fe/MIL-101(Cr) catalysts displayed superior OER/ORR catalytic activities than original sample in the alkaline electrolyte, and the activities of examples affected by the specific surface area, pore volume and molar ratio of Co/Fe. In the alkaline electrolyte 80Co-20Fe/MIL-101(Cr) showed good OER catalytic activity, at 0.9 V (vs. Ag/AgCl), the current density of OER was 36.5 mA·cm-2; 50Co-50Fe/MIL-101(Cr) showed good ORR catalytic activity, at -0.3 V the current density of OER was -1.85 mA·cm-2, and showed a good stability of ORR, in the 50000 s, ORR activity rate was about 82%.We used nitric acid cobalt as metal salt and use 2-methylimidazole as ligands to prepare precursor via a simple ligand synthetic process. The derivants of monometal coordination complexes were synthesized via carbonizing precursor under nitrogen protecting. After nitriding treatment, the OER/ORR catalytic activities and stabilities of derivants of monometal coordination complexes catalysts increased significantly compared with the pristine samples. Especially catalyst treated in nitrogen at 900? has the best OER catalytic performance. At 0.9 V (vs. Ag/AgCl), its OER current density of OER was 98.06 mA·cm-2. Catalyst treated in nitrogen at 700? owned the best ORR catalytic performance. Its onset potential at 0.020 V. At -0.3 V its current density reached the limit of the value of -4.15 mA·cm-2. In all catalysts, the catalyst treated in nitrogen at 700? has the best bifunctional OER/ORR catalytic performance and its bifunctional stability was also excellent. After carbonizing, the samples has improved activity and stability, because after carbonizing the precursor internal cobalt reduced to metallic cobalt and some of the carbon structure was generated to promote bifunctional catalytic activity and stability of the samples.With Co/Zn molar ratio was 3:2, and 2-methylimidazole as ligands, we prepared bimetal complexes and used the bimetal complexes as a precursor. The derivants of bimetal coordination complexes were synthesized via carbonizing precursor under nitrogen protecting. After nitriding treatment, the OER/ORR catalytic activities and stabilities of derivants of monometal coordination complexes catalysts increased significantly compared with the pristine samples. Especially catalyst treated in nitrogen at 700? has the best OER/ORR catalytic performance. At 0.9 V (vs. Ag/AgCl), its OER current density of OER was 100.71 mA·cm-2. Its onset potential at -0.085 V. At -0.3 V its current density has reached the limit of the value of -4.93 mA·cm-2. In all catalysts, the catalyst treated in nitrogen at 700? has the best bifunctional OER/ORR catalytic performance and its bifunctional stability was also excellent. After carbonizing, the samples has improved activity and stability, because after carbonizing the precursor internal cobalt reduced to metallic cobalt and cobalt metal particles outside wrapped generate cobalt oxide and some of the carbon structure, promote bifunctional catalytic activity of the samples.