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.

FeOOH/CeO2 heterolayered nanotubes supported on Ni foam as efficient oxygen evolution electrocatalysts are reported. The hybrid structure can obviously promote the catalytic performance for the oxygen evolution reaction, such as low onset potential, high electroactivity, and excellent long-term durability. This study provides a new route to the design and fabrication of electrocatalysts with high electroactivity and durability for oxygen evolution.

Low-cost transition-metal dichalcogenides (MS) have attracted great interest as alternative catalysts for hydrogen evolution. However, a significant challenge is the formation of sulfur-hydrogen bonds on MS (S-H), which will severely suppress hydrogen evolution reaction (HER). Here we report Cu nanodots (NDs)-decorated NiS nanotubes (NTs) supported on carbon fibers (CFs) (Cu NDs/NiS NTs-CFs) as efficient electrocatalysts for HER in alkaline media. The electronic interactions between Cu and NiS result in Cu NDs that are positively charged and can promote water adsorption and activation. Meanwhile, NiS NTs are negatively charged and can weaken S-H bonds formed on catalyst surfaces. Therefore, the Cu/NiS hybrids can optimize H adsorption and desorption on electrocatalysts and can promote both Volmer and Heyrovsky steps of HER. The strong interactions between Cu and NiS cause the Cu NDs/NiS NTs-CFs electrocatalysts to exhibit the outstanding HER catalytic performance with low onset potential, high catalytic activity, and excellent stability.

Iron-substituted CoOOH porous nanosheet arrays grown on carbon fiber cloth (denoted as Fe Co OOH PNSAs/CFC, 0≤x≤0.33) with 3D hierarchical structures are synthesized by in situ anodic oxidation of α-Co(OH) NSAs/CFC in solution of 0.01 m (NH ) Fe(SO ) . X-ray absorption fine spectra (XAFS) demonstrate that CoO octahedral structure in CoOOH can be partially substituted by FeO octahedrons during the transformation from α-Co(OH) to Fe Co OOH, and this is confirmed for the first time in this study. The content of Fe in Fe Co OOH, no more than 1/3 of Co, can be controlled by adjusting the in situ anodic oxidation time. Fe Co OOH PNSAs/CFC shows superior OER electrocatalytic performance, with a low overpotential of 266 mV at 10 mA cm , small Tafel slope of 30 mV dec , and high durability.

The search for high active, stable, and cost-efficient hydrogen evolution reaction (HER) electrocatalysts for water electrolysis has attracted great interest. The coordinated water molecules in the hydronium ions will obviously reduce the positive charge density of H and hamper the ability of H to receive electrons from the cathode, leading to large overpotential of HER on nonprecious metal catalysts. Here we realize Pt-like hydrogen evolution electrocatalysis on polyaniline (PANI) nanodots (NDs)-decorated CoP hybrid nanowires (HNWs) supported on carbon fibers (CFs) (PANI/CoP HNWs-CFs) as PANI can effectively capture H from hydronium ions to form protonated amine groups that have higher positive charge density than those of hydronium ions and can be electro-reduced easily. The PANI/CoP HNWs-CFs as low-cost electrocatalysts show excellent catalytic performance toward HER in acidic solution, such as super high catalytic activity, small Tafel slope, and superior stability.