NiS₂@MoS₂ Nanospheres Anchored on Reduced Graphene Oxide: A Novel Ternary Heterostructure with Enhanced Electromagnetic Absorption Property

A Highly Efficient Electromagnetic Wave Absorption System with Graphene Embedded in Hybrid Perovskite

To cope with the explosive increase in electromagnetic radiation intensity caused by the widespread use of electronic information equipment, high-performance electromagnetic wave (EMW)-absorbing materials that can adapt to various frequency bands of EMW are also facing great demand. In this paper, CH3NH3PbI3/graphene (MG) high-performance EMW-absorbing materials were innovatively synthesized by taking organic-inorganic hybrid perovskite (OIHP) with high equilibrium holes, electron mobility, and accessible synthesis as the main body, graphene as the intergranular component, and adjusting the component ratio. When the component ratio was 16:1, the thickness of the absorber was 1.87 mm, and MG's effective EMW absorption width reached 6.04 GHz (11.96-18.00 GHz), achieving complete coverage of the Ku frequency band. As the main body of the composite, CH3NH3PbI3 played the role of the polarization density center, and the defects and vacancies in the crystal significantly increased the polarization loss intensity; graphene, as a typical two-dimensional material distributed in the crystal gap, built an efficient electron transfer channel, which significantly improved the electrical conductivity loss strength. This work effectively broadened the EMW absorption frequency band of OIHP and promoted the research process of new EMW-absorbing materials based on OIPH.

MoS2 decorated on one-dimensional MgFe2O4/MgO/C composites for high-performance microwave absorption

Advanced microwave absorption (MA) materials have attracted widespread attention to meet the challenges of electromagnetic (EM) pollution. Herein, MgFe₂O₄/MgO/C fibers were successfully prepared via electrospinning technology and carbonization, and their surfaces were coated by MoS₂ via hydrothermal method. The EM wave absorption performance of composites was enhanced due to the introduction of MoS₂. The results showed that the EM wave absorption performance of MgFe₂O₄/MgO/C could not meet the requirements due to low dielectric loss and poor impedance matching. The performance of the composites was improved after coating of MoS₂, which showed the strong wave absorption capability and the broad absorption bandwidth. The optimal reflection loss (RL) is -56.94 dB at 9.5 GHz and the effective absorption bandwidth is 3.9 GHz (8.08-11.98 GHz) with a thickness of 2.7 mm. The excellent MA performance can be mainly attributed to excellent synergistic effect between MgFe₂O₄/MgO/C and MoS₂. Furthermore, MoS₂ also contributes to dielectric loss and ideal impedance matching. MgFe₂O₄/MgO/C@MoS₂ composites may be utilized for lightweight and high-efficient MA materials.

Fabrication of one-dimensional ZnFe2O4@carbon@MoS2/FeS2 composites as electromagnetic wave absorber

In this work, one-dimensional (1D) ZnFe₂O₄@carbon@MoS₂/FeS₂ composites were synthesized by hydrothermal method, magnetic-field-induced distillation-precipitation polymerization and high-temperature carbonization. The structure, morphology, composition, magnetic performance and electromagnetic (EM) wave absorbing properties of the composites were systematically studied. The composites show strong microwave absorption (MA) capacity with a minimum reflection loss (RL_min) value of -52.5 dB at 13.2 GHz, and have an effective absorption frequency range of 10.10-15.08 GHz with a bandwidth of 4.98 GHz when the thickness is 2.23 mm. It is expected that as-synthesized 1D ZnFe₂O₄@carbon@MoS₂/FeS₂ composites can be a promising EM wave absorption material.

Polypyrrole Chains Decorated on CoS Spheres: A Core-Shell Like Heterostructure for High-Performance Microwave Absorption

Cobalt sulfide composites have exhibited great potential in terms of microwave absorption, owing to their low price, relatively high capacitance, and excellent electrocatalytic activity. Thus, a novel core-shell like structure comprising cobalt sulfide@polypyrrole (CoS@PPy) composite was synthesized by a facile solvothermal synthesis method and in situ polymerization. When coated by the heterostructure polypyrrole aerogel, CoS@PPy composite exhibited excellent microwave absorption properties with an optimal reflection loss (RL) of -41.8 dB at 6.96 GHz. Furthermore, the absorption bandwidth (RL < -10 dB) of 5.4 GHz could be reached at a coating thickness of 2.05 mm, probably attributing to the synergistic effect of good impedance matching, interfacial polarization, dipole polarization, and conductivity loss. Moreover, this work proposed a loss mechanism mode which probably occurred in the CoS@PPy composites. It was demonstrated that the CoS@PPy composite is a promising material in the field of electromagnetic wave absorption.

Ni–Mo modified metal–organic frameworks for high-performance supercapacitance and enzymeless H2O2 detection

The growth process for A(B)-Ni_xMo_y-MOFs@AAC hybrids.

Retracted Article: The influence of gradient and porous configurations on the microwave absorbing performance of multilayered graphene/thermoplastic polyurethane composite foams

Single-layer graphene/TPU composite foams with different graphene content were prepared through a thermally induced phase separation (TIPS) process. Multilayer graphene/TPU composite foams were fabricated by bonding single-layer foams together. The arrangement of single-layer graphene/TPU composite foams in different orders could realize a gradient distribution of the graphene to endow the multilayer foams with good impedance matching characteristics. Facile regulation of the effective absorption bandwidth (EB) value and minimum reflection loss (RLmin) have been realized by adjusting the thickness and layer number or altering the combinatorial mode of single-layer foams with different graphene contents to endow these multilayered composite foams with optimal microwave-absorbing (MA) properties. In addition, the mechanism of microwave dissipation by gradient multilayers and porous structures has been elucidated. The EB values of the multilayer foams were all wider than those of their corresponding single-layer foams with the same graphene content and multilayer foams displayed much lower RLmin than single-layer foams. Among all the multilayer foams, 2L graphene/TPU composite foams with a thickness of 5 mm exhibit the widest EB value of 9.9 GHz and the lower RLmin (-36.7 dB) while 5L graphene/TPU composite foams with a thickness of only 2.5 mm show the lowest RLmin of -43.7 dB and wider EB values (5.3 GHz).

NiS2@rGO Nanosheet Wrapped with PPy Aerogel: A Sandwich-Like Structured Composite for Excellent Microwave Absorption

To reduce electromagnetic pollution as well as increase the accuracy of high-precision electronic equipment, more attention has been paid to new electromagnetic wave (EMW) absorbing materials, which have the advantages of strong absorption, wide absorption bands, and a narrow thickness. In this study, a novel ternary type of the NiS2@rGO/polypyrrole (PPy) sandwich-like structured composites was synthesized via a facile two-step method, in which the hydrothermal method was used to prepare NiS2@rGO binary composites and then the in situ polymerization method was used to synthesize the PPy, which acted as the outer layer of the sandwich-like structure. The morphologies and electromagnetic absorption performance of the NiS2@rGO/PPy were measured and investigated. A sample with 6 wt% NiS2@rGO/PPy loading paraffin-composite obtained an outstanding reflection loss (RL) of -58.7 dB at 16.44 GHz under a thickness of 2.03 mm. Simultaneously, the effective electromagnetic wave absorption bandwidth for RL < -10 dB, which covered 7.04 to 18.00 GHz (10.96 GHz), was achieved by changing the thickness of the absorber from 2.0 to 3.5 mm. The results not only suggest that the NiS2@rGO/PPy composite has excellent performance in the field of EMW absorption but also prove that the novel sandwich-like structure can contribute to appropriate impedance matching through multiple relaxation and interfacial polarization processes.