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To meet the ever-growing clean energy technology, developing effective catalysts for the oxygen evolution reaction (OER) is imperative for boosting the efficiency of electrochemical water splitting. This work reports Pd nanoparticle-interspersed nickel cobalt hydroxide carbonate nanothorn-coated copper hydroxide nanotube arrays grown on a copper foam (CH@NCHC NT-Pd/CF) as highly efficient OER electrocatalytic electrodes. The nanothorns and open-structured nanotubes have large surface areas and plenty of active sites. Particularly, the interfacial interaction between Pd nanoparticles and NCHC nanothorns causes charge transfer and redistribution, which are highly beneficial to promoting OER. The unique 3D integrated construction also can accelerate the electron and mass transfer and improve structural stability. Owing to the above merits, CH@NCHC NT-Pd/CF shows excellent OER electrocatalytic activity and stability in alkaline solution, delivering a current density of 100 mA cm–2 at a low overpotential of 20...

Unique octahedral yolk‐shell Cu2O@Co(OH)2 nanocages are synthesized by a facile Cu2O self‐templated strategy as efficient glucose oxidation electrocatalysts. Amorphous Co(OH)2 nanoflakes are formed as octahedral shells through coordinating etching conversion from part of Cu2O templates. The un‐etched crystalline Cu2O octahedrons are then remained as cores and voids exist between the cores and shells. The special structure endow these yolk‐shell heterostructure nanocages with abundant active sites, large surface area, and synergistic effect between Cu2O and Co(OH)2. The octahedral yolk‐shell Cu2O@Co(OH)2 nanocages demonstrate superior electrocatalytic activity for glucose oxidation in terms of high sensitivity of 1340 μA cm−2 mM−1, low detection limit of 2 μM, wide linear sensing range, and long‐term stability. This strategy might shed lights on the synthesis of various yolk‐shell heterostructure nanocages with controllable structures and enhanced catalytic performances.

Although integrated energy storage devices, such as in-plane micro-supercapacitors (MSCs), are attractive for powering portable microelectronic devices, it is still challenging to develop patterning techniques with high practicability and to rationally design and fabricate electrochemically active materials using feasible procedures. Here, we propose a facile solution-immersion method of fabricating interdigitated copper electrodes with an in situ converted array of Cu(OH)2@FeOOH nanotubes (NTs). A copper current collector can be patterned together with widely employed copper circuits by a facile copper-patterning approach based on cost-effective electroless catalytic deposition of copper with patterned Ag catalysts, which is greatly conducive to the integration of in-plane energy storage devices into microelectronic systems. Furthermore, the rationally designed array of Cu(OH)2@FeOOH NTs, which was converted in situ from the patterned copper electrodes, was demonstrated to be an excellent electrochemically active material with advantages that included a porous structure with a large specific surface area, excellent wettability by the electrolyte, short ion diffusion lengths and one-dimensional electron transport pathway. The resulting MSC devices that were fabricated with the interdigitated Cu(OH)2@FeOOH/Cu electrodes exhibited a high specific capacitance (58.0 mF cm−2 at 0.1 mA cm−2), a high energy density (18.07 μW h cm−2), excellent cycling stability and desirable flexibility.

Developing highly efficient and low-cost oxygen evolution reaction (OER) electrocatalysts is highly demanded, as the OER is recognized as a key half-reaction in water splitting for producing hydrogen; however, this still remains a great challenge. Herein, we design three-dimensional (3D) tubular hierarchical core–shell electrocatalysts for the OER using a simple and highly controllable two-step method. The large-scale tubular Cu(OH)2 arrays are directly grown on Cu foam (CF) at room temperature, followed by the growth of highly porous CoNi carbonate hydroxides (CH) via a low-temperature hydrothermal method on the walls of these Cu(OH)2 nanotubes (NTs). The hollow and open-structured core–shell hierarchical Cu(OH)2@CoNiCH NTs/CF electrode with a large surface area and numerous mesoporous and short diffusion paths can provide many active sites, fast electron transport and easy accessibility of water, leading to an excellent OER activity in an alkaline electrolyte with an overpotential of 288 mV and 326 mV at a current density of 30 mA cm−2 and 100 mA cm−2, respectively, also with robust durability. This new structure would open an avenue for the advancement of highly efficient OER electrocatalysts.

Porous octahedral PdCu alloy nanocages are prepared by templating against Cu2O together with the disproportionation and displacement reactions at room temperature. Through tuning the molar ratios of the Pd/Cu precursors (PdCl42−/Cu2O), the morphology and the electrocatalysis of the octahedral PdCu nanocages can be controlled. The PdCu-5 (Pd/Cu precursor ratio of 1 : 5) nanocages exhibit superior electrocatalytic activity (1090 mA mgPd−1) towards the methanol oxidation reaction, 2.9 times higher than that of the commercial Pd/C catalyst, with remarkable durability. The combined characterization by SEM, TEM, XRD and XPS demonstrated that the excellent performance and durability of the PdCu-5 nanocages can be ascribed to their excellent hollow and porous structures as well as the electronic effect between the noble metal Pd and the cheap metal Cu. Herein, this kind of nanomaterial with novel cage-like structures is a promising catalyst for direct methanol fuel cells (DMFCs).