Constructing hollow coordination polymers such as metalorganic frameworks, and Prussian blue analogs (PBAs) to fulfill diverse applications still remains a great challenge and requires extensive investigations. Here, we report a straightforward one-step strategy to construct hollow bimetallic CoFe-PBA. The morphology evolution process is carefully investigated as a function of aging time and relative reactant ratio, proving that the Co 2+ -to-[Fe(CN) 6 ] 3− (Co/Fe) ratio is crucial for obtaining the hollow structure, which is revealed as an orientated dissolution− recrystallization process driven by supersaturation. The hollow CoFe-PBA acts as an ideal precursor for the derived synthesis of ternary Co-Fe-P, which provides promising performance for the oxygen evolution reaction, with a low η 10 = 235 mV vs reversible hydrogen electrode and a Tafel slope of 34 mV dec −1 . This study proposes a new method for the design and construction of hollow PBAs for further conversion into highly efficient catalyst materials.

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Graphene quantum dots (GQDs) have wide prospective applications for optoelectronic fields owing to their unique characteristics, such as tunable bandgaps, high chemical and optical stability, as well as good biocompatibility. In this work, we offered a convenient proposal to obtain uniform blue-green emissive GQDs and modified efficient orange-emitting graphene quantum dots (D-GQDs) derived from fullerene (C60) under acid-free conditions. The as-prepared D-GQDs demonstrate remarkable conversion efficiency, for which the quantum yield is up to 52.4% with an emission peak of 617 nm. Also, GQDs and D-GQDs were blended with poly­(vinyl alcohol) (PVA) to prepare transparent photoluminescent films, which show excellent flexibility and preferable white emission property meeting the requirements of commercial white LEDs.

MgO/NiFe/MgO trilayers, the new development in highly sensitive anisotropic magnetoresistance (AMR) sensor film materials, exhibit severely reduced magnetoresistance ratios at small NiFe thicknesses. By inserting ultrathin NiFe(І) layers into the top and bottom MgO layers of MgO/NiFe/MgO trilayers, films with a structure of MgO/NiFe(І)/MgO/NiFe/MgO/NiFe(І)/MgO were designed and synthesized. The AMR value can be significantly enhanced for thin NiFe films due to the improved specular reflections of electrons at both NiFe/MgO interfaces. For a thin NiFe film with the structure of MgO/NiFe(І)(1.5 nm)/MgO/NiFe(5 nm)/MgO/NiFe(І)(1.5 nm)/MgO, the AMR value was greatly enhanced to as high as 2.71%, an increase of 37% over MgO/NiFe(5 nm)/MgO film.

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