Co(OH)2 Nanoparticle‐Encapsulating Conductive Nanowires Array: Room‐Temperature Electrochemical Preparation for High‐Performance Water Oxidation Electrocatalysis

• Published in: Advanced materials (Weinheim) 2018-03, Vol.30 (9), p.n/a
• Main Authors: Wu, Dan, Wei, Yicheng, Ren, Xiang, Ji, Xuqiang, Liu, Yiwei, Guo, Xiaodong, Liu, Zhiang, Asiri, Abdullah M., Wei, Qin, Sun, Xuping
• Format: Article
• Language: English
• Subjects: Catalysis; Catalytic activity; Co(OH)2 nanoparticles; Cobalt; conductive nanowire arrays; Conductivity; Electrocatalysis; Encapsulation; Materials science; Metal foams; Nanoparticles; Nanowires; Oxidation; Room temperature; room‐temperature anodization; Tetracyanoquinodimethane; water oxidation
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.201705366

It is highly desired but still remains challenging to design and develop a Co‐based nanoparticle‐encapsulated conductive nanoarray at room temperature for high‐performance water oxidation electrocatalysis. Here, it is reported that room‐temperature anodization of a Co(TCNQ)2 (TCNQ = tetracyanoquinodimethane) nanowire array on copper foam at alkaline pH leads to in situ electrochemcial oxidation of TCNQ− into water‐insoluable TCNQ nanoarray embedding Co(OH)2 nanoparticles. Such Co(OH)2‐TCNQ/CF shows superior catalytic activity for water oxidation and demands only a low overpotential of 276 mV to drive a geometrical current density of 25 mA cm−2 in 1.0 m KOH. Notably, it also demonstrates strong long‐term electrochemical durability with its activity being retrained for at least 25 h, a high turnover frequency of 0.97 s−1 at an overpotential of 450 mV and 100% Faradic efficiency. This study provides an exciting new method for the rational design and development of a conductive TCNQ‐based nanoarray as an interesting 3D material for advanced electrochemical applications. A Co(OH)2 nanoparticle‐encapsulating conductive tetracyanoquinodimethane (TCNQ) nanowire array on copper foam is prepared using an in situ electrochemical oxidation method to form a water‐insoluable conductive TCNQ nanoarray. This array effectively entraps Co(OH)2 nanoparticles at alkaline pH. Such Co(OH)2‐TCNQ/CF requires an overpotential as low as 276 mV to drive a geometrical current density of 25 mA cm−2 in 1.0 M KOH, with strong long‐term electrochemical durability.