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) (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) nanoparticles. Such Co(OH) -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 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 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.

It is highly desired to develop efficient earth-abundant electrocatalysts for the oxygen evolution reaction (OER) in alkaline media. In this communication, we report the in situ electrochemical conversion of a nanoarray of Cu(tetracyanoquinodimethane), Cu(TCNQ), an inorganic-organic hybrid, on Cu foam into CuO nanocrystals confined in a highly conductive nanoarray via anode oxidation. As a 3D catalyst electrode, the resulting CuO-TCNQ/CF shows high OER activity and demands an overpotential of only 317 mV to drive a geometrical catalytic current density of 25 mA cm. Notably, this catalyst also demonstrates strong long-term electrochemical durability. This study provides us with a universal strategy toward topotactic room-temperature preparation of conductive nanoarrays with confined transition metal nanocatalysts for practical applications.

Energy conversion and storage systems such as water splitting metal-air batteries require high-performance and durable oxygen evolution reaction (OER) catalysts. Herein, we report the in situ development of self-standing CoO nanorods array on Co foil (CoO NA/CF) as a 1D OER catalyst electrode. Such CoO NA/CF only needs overpotential of 308 mV to drive a geometrical catalytic current density of 15 mA cm in 1.0 M KOH with good long-term electrochemical durability. In addition, this catalyst achieves a high turnover frequency of 0.646 mol O s at overpotential of 410 mV.

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