화학공학소재연구정보센터
Journal of Catalysis, Vol.377, 20-27, 2019
Highly active M2P2O7@NC (M = Co and Zn) for bifunctional electrocatalysts for ORR and HER
Tuning the coordination environment between metal centers and organic ligands is a promising way to design of the precursors of electrocatalysts for water splitting or other renewable energy options. In this work, a novel coordinated polymer was prepared feasibly in polyvinyl pyrrolidone (PVP) aqueous solution using aminotrimethylene phosphonic acid (ATMP, L-1) and 2-methylimidazole (MeMI, L-2) as ligands with the ratio of 2:5, Co2+ and Zn2+ as metal centers. Based on the concept of acid-base neutralization reaction, the proton-transfer induced "deprotonation and protonation" for L-1 and L-2, respectively. Thus, the coordination was dominated by the deprotonated L-1. Owing to also partial of protonated L-2 adsorbed as "counter ions", carbonization of the obtained precursor at 800 degrees C under N-2 atmosphere endows the pyrolysis product with nitrogen-doped carbon supported metal pyrophosphate (M2P2O7@NC). Thus, the resulting M2P2O7@NC exhibits the enhanced and durable ORR and HER performance. For ORR in 0.1 M KOH, an enhanced onset potential (0.925 V vs. RHE), half wave potential (0.793 V vs. RHE) and diffusion limiting current (6.132 mA cm(-2)) can be obtained comparable to those of Pt/C. For HER in 0.5 M H2SO4, it only needs an over potential of 180 mV to realize a current density of 10 mA cm(-2). (C) 2019 Elsevier Inc. All rights reserved.