Efficient Hydrogen Evolution Electrocatalysis Using Cobalt Nanotubes Decorated with Titanium Dioxide Nanodots.

TiO2 Co nanotubes decorated with nanodots (TiO2 NDs/Co NSNTs-CFs) are reported as high-performance earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) in alkaline solution. TiO2 NDs/Co NSNTs can promote water adsorption and optimize the free energy of hydrogen adsorption. More importantly, the absorbed water can be easily activated in the presence of the TiO2 -Co hybrid structure. These advantages will significantly promote HER. TiO2 NDs/Co NSNTs-CFs as electrocatalysts show a high catalytic performance towards HER in alkaline solution. This study will open up a new avenue for designing and fabricating low-cost high-performance HER catalysts.

FeOOH/Co/FeOOH Hybrid Nanotube Arrays as High-Performance Electrocatalysts for the Oxygen Evolution Reaction.

Herein, we developed FeOOH/Co/FeOOH hybrid nanotube arrays (HNTAs) supported on Ni foams for oxygen evolution reaction (OER). The inner Co metal cores serve as highly conductive layers to provide reliable electronic transmission, and can overcome the poor electrical conductivity of FeOOH efficiently. DFT calculations demonstrate the strong electronic interactions between Co and FeOOH in the FeOOH/Co/FeOOH HNTAs, and the hybrid structure can lower the energy barriers of intermediates and thus promote the catalytic reactions. The FeOOH/Co/FeOOH HNTAs exhibit high electrocatalytic performance for OER, such as low onset potential, small Tafel slope, and excellent long-term durability, and they are promising electrocatalysts for OER in alkaline solution.

In Situ Derived NixFe1-xOOH/NiFe/NixFe1-xOOH Nanotube Arrays from NiFe Alloys as Efficient Electrocatalysts for Oxygen Evolution.

Herein, NixFe1-xOOH/NiFe/NixFe1-xOOH sandwich-structured nanotube arrays (SNTAs) supported on carbon fiber cloth (CFC) (NixFe1-xOOH/NiFe/NixFe1-xOOH SNTAs-CFC) have been developed as flexible high-performance oxygen evolution reaction (OER) catalysts by a facile in situ electrochemical oxidation of NiFe metallic alloy nanotube arrays during oxygen evolution process. Benefiting from the advantages of high conductivity, hollow nanotube array, and porous structure, NixFe1-xOOH/NiFe/NixFe1-xOOH SNTAs-CFC exhibited a low overpotential of ∼220 mV at the current density of 10 mA cm-2 and a small Tafel slope of 57 mV dec-1 in alkaline solution, both of which are smaller than those of most OER electrocatalysts. Furthermore, NixFe1-xOOH/NiFe/NixFe1-xOOH SNTAs-CFC exhibits excellent stability at 100 mA cm-2 for more than 30 h. It is believed that the present work can provide a valuable route for the design and synthesis of inexpensive and efficient OER electrocatalysts.