Taking the increasing issue of electromagnetic waves (EMW) pollution and the necessity for applications in extreme environments, there is a pressing requirement to create multifunctional microwave absorption materials (MAMs) to meet the current challenges. In this work, we achieved the successful combination of MXene sheets and metal organic framework (MOFs) derived CoNi@C magnetic alloys onto the three-dimensional (3D) melamine foam (MF) skeleton using vacuum impregnation and electrostatic self-assembly techniques. The obtained MF@MXene/CoNi@C composite foams achieved outstanding MA performance, with an optimal reflection loss (RL) value of –24.1 dB and a maximum effective absorption bandwidth (EAB) of 6.88 GHz at a thickness of 1.68 mm, effectively covering the whole Ku band. The superior MA performance is ascribed to the composite foams’ multi-component architecture, distinctive 3D porous structure, and the synergistic impact of multiple loss mechanisms. Moreover, the MF@MXene/CoNi@C composite foams demonstrate exceptional photothermal conversion, thermal insulation, and infrared stealth capabilities, effectively coping with the demands of applications in extreme environments. This work serves as a valuable resource and source of inspiration for the development of lightweight-broadband, multifunctional efficient MAMs.

At present, the research on highly active and stable nitrogen reduction reaction catalysts is still challenging work for the electrosynthesis of ammonia (NH₃). Herein, we synthesized atomically dispersed zinc active sites supported on N-doped carbon nanosheets (Zn/NC NSs) as an efficient nitrogen reduction reaction catalyst, which achieves a high ammonia yield of 46.62 μg h⁻¹ mg_cat.⁻¹ at −0.85 V (vs RHE) and Faradaic efficiency of 95.8% at −0.70 V (vs RHE). In addition, Zn/NC NSs present great stability and selectivity, and there is no significant change in NH₃ rate and Faradaic efficiencies after multiple cycles. The structural characterization shows that the active center in the nitrogen reduction reaction process is the Zn–N₄ sites in the catalyst. DFT calculation confirms that Zn/NC with Zn–N₄ configuration has a lower energy barrier for the formation of *NNH intermediate compared with pure N-doped carbon nanosheets (N-C NSs), thus promoting the hydrogenation kinetics in the whole nitrogen reduction reaction process.

2D-layered graphitic carbon nitride (g-C₃N₄) is regarded as a great prospect as a photocatalyst for H₂ generation. However, g-C₃N₄'s photocatalytic hydrogen evolution (HER) activity is significantly restricted by the recombination of photocarriers. We find that cobalt sulfide (CoS₂) as a cocatalyst can promote g-C₃N₄ nanosheets (NSs) to realize very efficient photocatalytic H₂ generation. The prepared CoS₂/g-C₃N₄ hybrids display highly boosted photocatalytic H₂ generation performance and outstanding cycle stability. The optimized 7%-CoS₂/g-C₃N₄ hybrids show a much improved photocatalytic H₂ generation rate of 36.2 ​μmol⁻¹ ​h⁻¹, which is about 180 times as much as bare g-C₃N₄ (0.2 ​μmol⁻¹ ​h⁻¹). In addition, the apparent quantum efficiency (AQE) of all the samples was computed under light at λ=370 ​nm, in which the AQE of 7%-CoS₂/g-C₃N₄ hybrids is up to 5.72%. The experimental data and the DFT calculation suggest that the CoS₂/g-C₃N₄ hybrid's excellent HER activity is attributable to the lower overpotential and the smaller Co-H bond activation energy for HER. Accordingly, the CoS₂ cocatalyst loading effectively boosts the photocatalytic performance of g-C₃N₄ for H₂ evolution. The project promotes fast development of high-efficiency photocatalysts and low-cost for photocatalytic H₂ generation.