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To improve the complexity and low catalytic performance and reduce the high cost of the traditional electrode preparation process for the sodium borohydride electro-oxidation reaction (BOR), in this work, a self-supported and efficient electrode material grown on nickel foam (CoNi/Co3O4/NF) was successfully designed using a simple hydrothermal synthesis method accompanied by the electrodeposition process. Benefiting from the three-dimensional nanoarray structure of CoNi/Co3O4/NF and the uniform distribution of Co and Ni modulating active sites by electrodeposition, the catalytic activity towards NaBH4 exhibits high efficiency. CoNi/Co3O4 exhibits excellent catalytic performance (up to 2157 mA cm−2 in 2 mol L−1 NaOH and 0.3 mol L−1 NaBH4), a high electrochemically active surface area (62.5 cm−2), and a low activation energy (15.56 kJ mol−1). The CoNi/Co3O4/NF electrode was further investigated on a direct sodium borohydride–hydrogen peroxide fuel cell (DBHPFC), which exhibited a maximum power density of 108.5 mW cm−2 and excellent stability. The excellent performance is mainly due to its unique nanoarray structure and electrodeposition distribution of Co and Ni active sites, which increases the electrochemical surface area and enhances the contact between the electrode and the electrolyte. [ABSTRACT FROM AUTHOR]

A novel polyoxometalate-based metal–organic framework templated by twin-Dawson clusters, [{Cu3(μ3-O)}2(trz)6Cu2(H2O)13][H1.73P2As1.73W16.27O62]·8.25H2O (1) (trz = 1,2,4-triazole), has been synthesized under hydrothermal conditions. In 1, there are two crystal distinct motifs: a 3D metal–organic nanotube framework and seven-connected Dawson clusters. It is worth mentioning that the 3D framework possesses nanotube-like channels. The twin-H1.73P2As1.73W16.27O62 clusters (abbreviated as P2(As/W)18 clusters) as templates occupy channels of the nanotube framework. To the best of our knowledge, this represents the first metal–organic nanotube framework templated by twin-Dawson clusters. The electrochemical experiments indicate that the 1-based glassy carbon electrode (1-GCE) possesses high catalytic efficiency and high stability toward reduction of inorganic bromate molecules and oxidation of the biological molecule ascorbic acid. The electrocatalytic efficiency towards the reduction of bromate in 1 M H2SO4 solution and oxidation of AA in N2 purged solution is ca. 848.4% and 896.8% (catalytic substrate: 0.5 mM), respectively. The current signal after 100 cycles exhibits almost no loss for 1-GCE. [ABSTRACT FROM AUTHOR]

A new polyoxovanadate-based metal–organic framework, [Cu(Pz)](V4O10) (1) (Pz = Pyrazine) has been synthesized under hydrothermal conditions. Single crystal X-ray diffraction analysis reveals that compound 1 displays a 3D framework with a rare reduced V4O102− layer. The electrochemical study shows that 1 exhibits bifunctional electrocatalytic activities toward reduction of iodate and oxidation of ascorbic acid. Surface photovoltage spectroscopy (SPS) and electric field induced surface photovoltage spectroscopy (EFISPS) measurements reveal that 1 has the behavior of an n-type semiconductor. In addition, 1 shows excellent photocatalytic activity for the decomposition of Rhodamine-B dye under visible light. [ABSTRACT FROM AUTHOR]