It is of high importance to design efficient electrocatalysts for the oxygen evolution reaction (OER) at alkaline pH. In this communication, we report the development of a Zn-doped NiS nanosheet array on Ni foam (Zn-NiS/NF) as a high-performance and durable electrocatalyst for the OER. Such Zn-NiS/NF drives a catalytic current density of 100 mA cm with the requirement of an OER overpotential of 330 mV, 90 mV less than that for NiS/NF. Furthermore, Zn-NiS/NF demonstrates excellent long-term electrochemical durability maintaining its activity at an overpotential of 300 mV for 20 h.

It is highly desired to enhance the catalytic activity of oxygen evolution reaction (OER) electrocatalysts made of earthabundant elements. In this Letter, we report that the OER activity of a CuO nanoarray can be largely enhanced by Co doping. In 1.0 M KOH, the Co-CuO nanoarray on copper foam requires a current densities of 50 and 100 mA cm −2 at overpotentials of only 299 and 330 mV, respectively. It also shows superior long-term durability over 15 h with a turnover frequency of 0.056 mol O 2 s −1 at an overpotential of 300 mV.

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.

Developing earth-abundant and high-performance electrocatalysts toward the alkaline hydrogen evolution reaction (HER) is highly desired. In this communication, we report a Mn-doped NiP nanosheet array on nickel foam (Mn-NiP/NF) as a high-efficiency electrocatalyst for the HER in alkaline solutions. This Mn-NiP/NF can drive 20 mA cm at an overpotential of 103 mV in 1.0 M KOH, which is 82 mV less than that for NiP/NF. In addition, it also demonstrates excellent long-term electrochemical durability for at least 25 h. This work offers us a promising catalyst material for water-splitting devices for large-scale production of hydrogen fuels.

In 1.0 M KOH, CoP–CeO2 nanosheets film on Ti mesh (CoP–CeO2/Ti) attains 10 mA cm−2 at overpotential of 43 mV due to its lower water dissociation free energy and more optimal hydrogen adsorption free energy than CoP.