Herein, the advances in low-dimensional core-shell EM wave absorption materials are outlined and a selection of the most remarkable examples is discussed. The derived key information regarding dimensional design, structural engineering, performance, and structure-function relationship are comprehensively summarized. Moreover, the investigation of the cuttingedge mechanisms is given particular attention. Additional applications, such as oxidation resistance and self-cleaning functions, are also introduced. Finally, insight into what may be expected from this rapidly expanding field and future challenges are presented.

Two-dimensional materials, especially the newly emerging MXene, have attracted numerous interests in the fields of energy conversion/storage and electromagnetic shielding/absorption. However, the inherently inevitable aggregation and absence of magnetic loss of MXene considerably limit its electromagnetic absorption application. The introduction of magnetic component and favorable structural engineering are the alternatives to improve the microwave absorption (MA) performance. Herein, we report a spheroidization strategy to assemble double-shell MXene@Ni microspheres, where the commonly lamellar MXene are reshaped into three-dimensional microspheres that provide the substrate for oriented growth of Ni nanospikes. Whereas this structural feature offers massive accessible active surfaces that effectively promote the dielectric loss ability, the introduction of magnetic Ni nanospikes enables the additional magnetic loss capacity. Benefiting from these merits, the synthesized 3D MXene@Ni microspheres exhibit superior MA performance with the minimum reflection loss value of −59.6 dB at an ultrathin thickness (∼1.5 mm) and effective absorption bandwidth of 4.48 GHz. Moreover, the electron holography results reveal that the high-density anisotropy magnetism plays an important role in the improvement of MA performance, which provides an insight for the design of MXene-based materials as high-efficient microwave absorbers.

Hollow nanostructures with mesoporous shells are attractive for their advantageous structure-dependent high-efficiency electrochemical catalytic performances. In this work, a novel nanostructure of Fe-doped CoP hollow triangle plate arrays (Fe-CoP HTPAs) with unique mesoporous shells is designed and synthesized through a room-temperature postsynthetic ligand exchange reaction followed by a facile phosphorization treatment. The mild postsynthetic ligand exchange reaction of the presynthesized ZIF-67 TPAs with K [Fe(CN) ] in an aqueous solution at room temperature is of critical importance in achieving the final hollow nanostructure, which results in the production of CoFe(II)-PBA HTPAs that not only determine the formation of the interior voids in the nanostructure, but also provide the doping of Fe atoms to the CoP lattice. As expected, the as-prepared mesoporous Fe-CoP HTPAs exhibit pronounced activity for water splitting owing to the advantages of abundant active reaction sites, short electron and ion pathways, and favorable hydrogen adsorption free energy (ΔG ). For the hydrogen and oxygen evolution reactions with the Fe-CoP HTPAs in alkaline medium, the low overpotentials of 98 and 230 mV are observed, respectively, and the required cell voltage toward overall water splitting is only as low as 1.59 V for the driving current density of 10 mA cm .

A self-templating strategy was used to prepare novel mesoporous Cu-doped Co9S8 rectangular nanotube arrays (Cu-Co9S8 NTAs) as an advanced electrode for all-solid-state asymmetric supercapacitors, which deliver a high energy density of 71.93 W h kg−1 at a power density of 750 W kg−1.