Multiferroic bismuth ferrite-based materials for multifunctional applications: Ceramic bulks, thin films and nanostructures

A p-type Ti(IV)-based metal–organic framework with visible-light photo-response

Recent progress in metal-organic frameworks-based hydrogels and aerogels and their applications

Synthesis, properties and applications of ZnO nanomaterials with oxygen vacancies: A review

Reported herein are two new polymorphic Co-MOFs (CTGU-5 and -6) that can be selectively crystallized into the pure 2D or 3D net using an anionic or neutral surfactant, respectively. Each polymorph contains a H2O molecule, but differs dramatically in its bonding to the framework, which in turn affects the crystal structure and electrocatalytic performance for hydrogen evolution reaction (HER). Both experimental and computational studies find that 2D CTGU-5 which has coordinates water and more open access to the cobalt site has higher electrocatalytic activity than CTGU-6 with the lattice water. The integration with co-catalysts, such as acetylene black (AB) leads to a composite material, AB&CTGU-5 (1:4) with very efficient HER catalytic properties among reported MOFs. It exhibits superior HER properties including a very positive onset potential of 18 mV, low Tafel slope of 45 mV dec−1, higher exchange current density of 8.6×10−4 A cm−2, and long-term stability.

Surfactant-Assisted Phase-Selective Synthesis of New Cobalt MOFs and Their Efficient Electrocatalytic Hydrogen Evolution Reaction.

We report the correlated d(0) ferromagnetism and photoluminescence in undoped single-crystalline ZnO nanowires synthesized by using a vapor transport method. We systematically tune the oxygen deficiency in the ZnO nanowires from 4% to 20% by adjusting the growth conditions, i.e., selecting different catalyst (Au or Ag) and varying the growth temperature. Our study suggests that oxygen vacancies induce characteristic photoluminescence and significantly boost the room-temperature ferromagnetism. Such undoped ZnO nanowires with tunable magnetic and optical properties are promising to find applications in multifunctional spintronic and photonic nanodevices.

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Correlated d 0 ferromagnetism and photoluminescence in undoped ZnO nanowires

Tuning metal–carboxylate coordination in crystalline metal–organic frameworks through surfactant media

Here, we report on a surfactant-thermal method to prepare four new 3-D crystalline heterometal–organic frameworks (HMOFs). The results indicate that our new strategy for growing crystalline materials in surfactant media has great potential for the synthesis of novel MOFs with various structures.

A surfactant-thermal method to prepare four new three-dimensional heterometal-organic frameworks.

A systematic study on the magnetic and electrical transport properties of single-phase wurtzite Zn1−xCuxO is performed. Efros variable range hopping dominates the conduction, which is accompanied by a ferromagnetic order up to 700 K for x>1%. Both the first-principles calculations and Cu/Al co-doping experiments suggest that the spontaneous spin polarization originates from the p-d exchange interaction between O 2p and Cu 3d orbitals. Furthermore, our results are consistent with the scenario that the intrinsic ferromagnetism is established through indirect interactions between bound magnetic polarons mediated by magnetic impurities.

Bound magnetic polarons and p-d exchange interaction in ferromagnetic insulating Cu-doped ZnO

We report that room-temperature ferromagnetism emerges at the interface formed between ZnO nanowire core and Al2O3 shell although both constituents show mainly diamagnetism. The interface-based ferromagnetism can be further enhanced by annealing the ZnO/Al2O3 core-shell nanowires and activating the formation of ZnAl2O4 phase as a result of interfacial solid-state reaction. High-temperature measurements indicate that the magnetic order is thermally stable up to 750 K. Transmission electron microscopy studies reveal the annealing-induced jagged interfaces, and the extensive structural defects appear to be relevant to the emergent magnetism. Our study suggests that tailoring the spinterfaces in nanostructure-harnessed wide-band-gap oxides is an effective route towards engineered nanoscale architecture with enhanced magnetic properties.

/pdf/emergent-ferromagnetism-in-zno-al2o3-core-shell-nanowires-2y9agnuc05.pdf

Mi He

Papers

Correlated d 0 ferromagnetism and photoluminescence in undoped ZnO nanowires

Tuning metal–carboxylate coordination in crystalline metal–organic frameworks through surfactant media

A surfactant-thermal method to prepare four new three-dimensional heterometal-organic frameworks.

Bound magnetic polarons and p-d exchange interaction in ferromagnetic insulating Cu-doped ZnO

Emergent ferromagnetism in ZnO/Al2O3 core-shell nanowires: Towards oxide spinterfaces