title: Creation of Ge-Nx-Cy Configures in Carbon Nanotubes: Origin of Enhanced Electrocatalytic Performance for Oxygen Reduction Reaction.
abstract: High-performance nitrogen and germanium codoped carbon nanotubes (N-Ge-CNTs) were synthesized as oxygen reduction reaction (ORR) catalysts by one-step sintering of carboxyethyl germanium sesquioxide and multiwalled CNTs in NH3 atmosphere. The ORR electrocatalytic activity evaluation was performed by using limited current density, selective reaction pathway, onset potential, H2O2 yields, and kinetic current density. In comparison with Ge or N solely doped CNTs, the codoped samples display more excellent ORR catalytic performance. It was observed that the codoped GeN3C, GeN4, and GeN4 + NC3 microstructures in N-Ge-CNTs are crucial to improving ORR catalytic performance, such as ideal 4 electron pathway (3.95) and positive onset potential (-0.08 V). The high ORR performance is attributed to the synergistic effect of N and Ge doping, which is capable of activating the π electrons of sp(2) hybridized orbital around carbon nantotubes. The ORR catalytic synergistic effect has also been verified by calculating the work function on the basis of density functional theory (DFT).
authors.affiliation: School of Environmental Science and Engineering, Collaborative Innovation Center for Marine Biomass Fibers, Qingdao University , Qingdao, 266071, P R China.
authors.forename: Xilin
authors.initials: X
authors.lastname: She
authors.affiliation: School of Environmental Science and Engineering, Collaborative Innovation Center for Marine Biomass Fibers, Qingdao University , Qingdao, 266071, P R China.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Li
authors.affiliation: School of Environmental Science and Engineering, Collaborative Innovation Center for Marine Biomass Fibers, Qingdao University , Qingdao, 266071, P R China.
authors.forename: Na
authors.initials: N
authors.lastname: Ma
authors.affiliation: School of Environmental Science and Engineering, Collaborative Innovation Center for Marine Biomass Fibers, Qingdao University , Qingdao, 266071, P R China.
authors.forename: Jin
authors.initials: J
authors.lastname: Sun
authors.affiliation: International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University , Xi'an, 710049, P R China.
authors.forename: Dengwei
authors.initials: D
authors.lastname: Jing
authors.affiliation: Key Laboratory of Carbon Materials Institute of Coal Chemistry, Chinese Academy of Sciences , Taiyuan, 030001, P R China.
authors.forename: Chengmeng
authors.initials: C
authors.lastname: Chen
authors.affiliation: Key Laboratory of Mesoscopic Chemistry of MOE and Jiangsu Provincial Lab for Nanotechnology, Institute of Theoretical and Computational Chemistry, School of Chemistry and Chemical Engineering, Nanjing University , Nanjing, 210046, P R China.
authors.forename: Lijun
authors.initials: L
authors.lastname: Yang
authors.affiliation: School of Environmental Science and Engineering, Collaborative Innovation Center for Marine Biomass Fibers, Qingdao University , Qingdao, 266071, P R China.|Queensland Micro- and Nanotechnology Centre (QMNC), Griffith University , Nathan, Brisbane, QLD 4111, Australia.
authors.forename: Dongjiang
authors.initials: D
authors.lastname: Yang
keywords: Ge/N codoping; carbon nanotubes; oxygen reduction reaction; synergistic effect