The novel Ti2-containing, sandwich-type 18-tungsto-2-arsenate(III) [(Ti(IV)O)2(α-As(III)W9O33)2](14-) (1) was successfully synthesized by the reaction of [TiO](2+) species with [α-As(III)W9O33](9-). The monolacunary polyanion 1 is solution-stable, and a further reaction with 1 equiv of phenylantimony(III) dichloride resulted in [C6H5Sb(III)(Ti(IV)O)2(α-As(III)W9O33)2](12-) (2). Both polyanions 1 and 2 were structurally characterized in the solid state and solution. Electrochemical studies were also performed on both polyanions.

The molecular self-assembled nanohybrids CdS QDs-POM-Au NPs can be synthesized by a convenient, efficient and environmentally friendly strategy. The POMs, which function as the reducing, encapsulating molecules and bridging molecules, not only successfully realize the strong coupling of the different nanoparticles, but also enhance the electron transfer among the components of the nanohybrids. More importantly, the present nanohybrids can effectively harvest visible light and show synergistic photocatalytic activity both in photoproduction of hydrogen and degradation of organic pollutants. This synthesis method is versatile and promising for the design and development of other new solar energy hybrid systems.

The oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are key catalytic processes for sustainable energy technologies, such as water electrolysis or fuel cells. Here, a novel metal oxide− nanostructured carbon composite is reported, which acts as OER and ORR electrocatalyst under technologically relevant conditions. A facile synthetic process allows the deposition of a molecular manganese vanadium oxide precursor, [Mn 4 V 4 O 17 (OAc) 3 ] 3− , on reduced graphene oxide. Simultaneously, the precursor is converted into insoluble nanostructured solid-state Mn−Voxide catalysts. Control of the synthetic conditions allows tuning of the electrocatalytic properties of the composites, leading to excellent and stable electrochemical reactivity. The electrocatalytic ORR and OER activity was evaluated in alkaline aqueous electrolyte and showed performance comparable with commercial Pt/C electrocatalysts. The study thus demonstrates how polyoxometalate precursors based on earth-abundant elements can be deposited on nanostructured carbon to give highperformance OER/ORR catalysts for alkaline water electrolysis. A new class of composite catalysts can in future be accessed by a facile fabrication route.

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