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Nano-network Ru with definite lattice defects on amorphous Co nanosheets is obtained for the first time. Amorphous Co support can promote the surface Ru to obtain special morphology and modified electronic structure, thus improving HER activity in alkaline solution. A current density of 10 mA cm−2 can be obtained only with an overpotential of 33.5 mV. [ABSTRACT FROM AUTHOR]

AuIr alloy nanoparticles were successfully prepared without using surfactants for the first time despite Au and Ir being immiscible according to phase diagrams. The lattice parameters of the AuIr alloy can be adjusted arbitrarily. The oxygen reduction reaction (ORR) activity of Au5Ir5 alloy is better than that of Au or Ir, and the oxygen evolution reaction (OER) activity of the Au5Ir5 alloy is as good as that of Ir in alkaline solution. [ABSTRACT FROM AUTHOR]

Electrolyzing water is an environmentally friendly and renewable way to obtain high purity hydrogen. Ruthenium has strong water dissociation ability and suitable hydrogen adsorption energy, so it is considered as one of the candidates of excellent electrocatalysts for hydrogen evolution in alkaline solution. The dynamic hydrogen bubble template (DHBT) is a good electrodeposition technology, which can obtain the 3D metal foams. However, as far as we know, there is no report on the preparation of Ru electrocatalyst by the DBHT method. In this work, the trumpet-shaped Ru on amorphous cobalt support (T-Ru/a-Co) is prepared by the DHBT electrodeposition for the first time. The defect locations are uniformly distributed on the surface of amorphous cobalt (a-Co), which can effectively lead to the formation of nano-bubble template in the DHBT process. However, this special morphology cannot be obtained on the surface of crystalline Co (c-Co). In addition, the electronic structure of T-Ru/a-Co has also been obviously modified, in which the proportion of Ru4+/Ru0 in T-Ru/a-Co has increased, accompanied by the change of binding energy of Ru. It only needs an overpotential of 49 mV to obtain a current density of 10 mA cm−2 for the T-Ru/a-Co. The specific activity (SA), turnover frequency (TOF) and mass activity (MA) of T-Ru/a-Co are 0.23 mA cm−2, 0.48 s−1 and 0.24 A mg−1, which are both higher than those of Pt/C, the disk-shaped Ru on the c-Co support (D-Ru/c-Co) and Ru/C, respectively. • The trumpet-shaped Ru is prepared by the dynamic hydrogen bubble template (DHBT) electrodeposition for the first time. • The amorphous Co can form nano-bubble template in DHBT process, but it can't be realized on the surface of crystalline Co. • The electronic structure of trumpet-shaped Ru has also been obviously modified. • The specific activity, turnover frequency and mass activity of trumpet-shaped Ru are both higher than those of Pt/C. [ABSTRACT FROM AUTHOR]

With the demand of renewable hydrogen energy, electrocatalytic water splitting is considered as the most promising method for hydrogen production. Herein, a simple synthesis of the nanoporous RuO 2 (NP-RuO 2) characterized by RuO(OH) 2 surface phase was reported. The physical characterization of the materials are achieved by transmission electron microscope (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray fluorescence (XRF) and X-ray photoelectron spectrometer (XPS). For HER activity, the NP-RuO 2 –450 electrode only needs 87 mV overpotential to obtain a current density of 10 mA cm−2, while RuO 2 generates the same current density at a relatively large overpotential (η = 142 mV). Notably, the HER activity of NP-RuO 2 –450 is also higher than that of Pt (10 mA cm−2, η = 103 mV). The specific activity of NP-RuO 2 –450 is still 2.4 times higher than that of RuO 2 reflecting the enhancement of the intrinsic activity. The OER activity of NP-RuO 2 –450 electrode has outperformed that of RuO 2. The apparent activity of NP-RuO 2 –450 is 3.5 times that of RuO 2 at an overpotential of 270 mV. For the specific activity, NP-RuO 2 –450 is still 1.9 times higher than that of RuO 2. Therefore, NP-RuO 2 –450 electrode could be used as a bifunctional catalyst for overall water splitting. The excellent HER and OER activities of the NP-RuO 2 –450 electrode could be attributed to the enhancement of electrochemical surface area of electrode material. However, the more important reason is that the new surface phase creation of hydroxides and the electronic structure modification of Ru. Unlabelled Image • A simple synthesis of the nanoporous RuO 2 (NP-RuO 2) characterized by RuO(OH) 2 surface phase was reported. • NP-RuO 2 electrode can be used as a bifunctional catalyst for overall water splitting for its good HER and OER activities. • The good activity of NP-RuO 2 electrode is attributed to the hydroxide formation and electronic structure modification. [ABSTRACT FROM AUTHOR]