Enhanced electron transport through a nanoforest-like structure of CoNi nanoalloy@nitrogen-doped carbon nanotubes for highly efficient catalysis of overall water splitting

• Published in: Applied surface science Vol. 517; p. 145841
• Main Authors: Li, Rui, Li, Xiaodong, Liu, Chunjiao, Ye, Min, Yang, Qiang, Liu, Zhongping, Xie, Lifeng, Yang, Guangcheng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2020
• Subjects: Bifunctional electrocatalyst; Cobalt-nickel nanoalloy; Fast electron transfer; Nitrogen-doped carbon tubes; Unique architecture; Water splitting; Bifunctional electrocatalyst; Water splitting; Fast electron transfer; Nitrogen-doped carbon tubes; Cobalt-nickel nanoalloy; Unique architecture
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.145841

[Display omitted] •Nanoforest-like structure of CoNi@NC-NCNTs was designed and prepared.•Nanoforest-like structure provides a 3D fast and continuous conductive network.•The hierarchical nanowires structure increases the quantity of active sites.•The CoNi@NC-NCNTs exhibits an excellent performance in overall water splitting. A major challenge of water splitting is to develop a robust bifunctional electrocatalyst. However, the catalytic effect of the reported materials is still unsatisfactory due to discrete electron transport, poor conductivity and limited active site. Herein, the nanoforest-like structure of CoNi@NC-NCNTs is fabricated by a facile carbonization-induced in situ growth strategy with nitrogen-doped carbon layer coated CoNi alloy nanowires (CoNi@NC) as trunks and intertwined nitrogen-doped carbon nanotubes as branches (NCNTs). The intertwined NCNTs grown on CoNi@NC nanowires not only build a highway of the electron transport between CoNi@NC nanowires, but also provide a continuous 3D conductive network for the whole electrocatalyst. Meantime, such structure increases the electrical conductivity and the catalytic activity site of CoNi@NC-NCNTs. Combined with the above advantages, the nanoforest-like CoNi@NC-NCNTs electrode exhibits high HER and OER catalytic performance in 1 M KOH solution with low overpotentials of 85 mV and 263 mV at 10 mA cm−2 and outstanding durability, respectively. The two-electrode electrolyzer assembled by CoNi@NC-NCNTs only requires 1.62 V to reach the current density of 10 mA cm−2. This paper provides a well-defined model for constructing highly efficient catalyst toward overall water splitting.