TY - JOUR
T1 - Highly Efficient Silver-Cobalt Composite Nanotube Electrocatalysts for Favorable Oxygen Reduction Reaction
AU - Yu, Areum
AU - Lee, Chongmok
AU - Lee, Nam Suk
AU - Kim, Myung Hwa
AU - Lee, Youngmi
N1 - Funding Information:
This work was financially supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (2014R1A2A2A05003769 for Y.L.) and (2014R1A1A2059791 for M.H.K.).
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/12/7
Y1 - 2016/12/7
N2 - This paper reports the synthesis and characterization of silver-cobalt (AgCo) bimetallic composite nanotubes. Cobalt oxide (Co3O4) nanotubes were fabricated by electrospinning and subsequent calcination in air and then reduced to cobalt (Co) metal nanotubes via further calcination under a H2/Ar atmosphere. As-prepared Co nanotubes were then employed as templates for the following galvanic replacement reaction (GRR) with silver (Ag) precursor (AgNO3), which produced AgCo composite nanotubes. Various AgCo nanotubes were readily synthesized with applying different reaction times for the reduction of Co3O4 nanotubes and GRR. One hour reduction was sufficiently long to convert Co3O4 to Co metal, and 3 h GRR was enough to deposit Ag layer on Co nanotubes. The tube morphology and copresence of Ag and Co in AgCo composite nanotubes were confirmed with SEM, HRTEM, XPS, and XRD analyses. Electroactivity of as-prepared AgCo composite nanotubes was characterized for ORR with rotating disk electrode (RDE) voltammetry. Among differently synthesized AgCo composite nanotubes, the one synthesized via 1 h reduction and 3 h GRR showed the best ORR activity (the most positive onset potential, greatest limiting current density, and highest number of electrons transferred). Furthermore, the ORR performance of the optimized AgCo composite nanotubes was superior compared to pure Co nanotubes, pure Ag nanowires, and bare platinum (Pt). High ethanol tolerance of AgCo composite nanotubes was also compared with the commercial Pt/C and then verified its excellent resistance to ethanol contamination.
AB - This paper reports the synthesis and characterization of silver-cobalt (AgCo) bimetallic composite nanotubes. Cobalt oxide (Co3O4) nanotubes were fabricated by electrospinning and subsequent calcination in air and then reduced to cobalt (Co) metal nanotubes via further calcination under a H2/Ar atmosphere. As-prepared Co nanotubes were then employed as templates for the following galvanic replacement reaction (GRR) with silver (Ag) precursor (AgNO3), which produced AgCo composite nanotubes. Various AgCo nanotubes were readily synthesized with applying different reaction times for the reduction of Co3O4 nanotubes and GRR. One hour reduction was sufficiently long to convert Co3O4 to Co metal, and 3 h GRR was enough to deposit Ag layer on Co nanotubes. The tube morphology and copresence of Ag and Co in AgCo composite nanotubes were confirmed with SEM, HRTEM, XPS, and XRD analyses. Electroactivity of as-prepared AgCo composite nanotubes was characterized for ORR with rotating disk electrode (RDE) voltammetry. Among differently synthesized AgCo composite nanotubes, the one synthesized via 1 h reduction and 3 h GRR showed the best ORR activity (the most positive onset potential, greatest limiting current density, and highest number of electrons transferred). Furthermore, the ORR performance of the optimized AgCo composite nanotubes was superior compared to pure Co nanotubes, pure Ag nanowires, and bare platinum (Pt). High ethanol tolerance of AgCo composite nanotubes was also compared with the commercial Pt/C and then verified its excellent resistance to ethanol contamination.
KW - bimetallic nanotubes
KW - cobalt
KW - electrocatalyst
KW - electrospinning
KW - oxygen reduction reaction
KW - silver
UR - http://www.scopus.com/inward/record.url?scp=85003003005&partnerID=8YFLogxK
U2 - 10.1021/acsami.6b11073
DO - 10.1021/acsami.6b11073
M3 - Article
AN - SCOPUS:85003003005
SN - 1944-8244
VL - 8
SP - 32833
EP - 32841
JO - ACS Applied Materials and Interfaces
JF - ACS Applied Materials and Interfaces
IS - 48
ER -