Achieving large-scale electrochemical CO₂ reduction to multicarbon products with high selectivity using membrane electrode assembly (MEA) electrolyzers in neutral electrolyte is promising for carbon neutrality. However, the unsatisfactory multicarbon products selectivity and unclear reaction mechanisms in an MEA have hindered its further development. Here, we report a strategy that manipulates the interfacial microenvironment of Cu nanoparticles in an MEA to suppress hydrogen evolution reaction and enhance C₂H₄ conversion. In situ multimodal characterizations consistently reveal well-stabilized Cu^δ+-OH species as active sites during MEA testing. The OH radicals generated in situ from water create a locally oxidative microenvironment on the copper surface, stabilizing the Cu^δ+ species and leading to an irreversible and asynchronous change in morphology and valence, yielding high-curvature nanowhiskers. Consequently, we deliver a selective C₂H₄ production with a Faradaic efficiency of 55.6% ± 2.8 at 316 mA cm⁻² in neutral media.

Electromagnetic pollution presents growing challenges due to the rapid expansion of portable electronic and communication systems, necessitating lightweight materials with superior shielding capabilities. While prior studies focused on enhancing electromagnetic interference (EMI) shielding effectiveness (SE), less attention is given to absorption‐dominant shielding mechanisms, which mitigate secondary pollution. By leveraging material science and engineering design, a layered structure is developed comprising rGOnR/MXene‐PDMS nanocomposite and a MXene film, demonstrating exceptional EMI shielding and ultra‐high electromagnetic wave absorption. The 3D interconnected network of the nanocomposite, with lower conductivity (10 ⁻³ –10 ⁻² S/cm), facilitates a tuned impedance matching layer with effective dielectric permittivity, and high attenuation capability through conduction loss, polarization loss at heterogeneous interfaces, and multiple scattering and reflections. Additionally, the higher conductivity MXene layer exhibits superior SE, reflecting passed electromagnetic waves back to the nanocomposite for further attenuation due to a π/2 phase shift between incident and back‐surface reflected electromagnetic waves. The synergistic effect of the layered structures markedly enhances total SE to 54.1 dB over the K _u ‐band at a 2.5 mm thickness. Furthermore, the study investigates the impact of hybridized layered structure on reducing the minimum required thickness to achieve a peak absorption (A) power of 0.88 at a 2.5 mm thickness.

5-hydroxymethyl furfural (HMF) is an important biomass-derived material for alkane bio-oil production. HMF is currently produced from edible glucose and fructose. Until recently, some researchers successfully applied ionic liquids to convert cellulose, a type of inedible biomass, to HMF. However, ionic liquids usually are toxic and/or require sophisticated skills to prepare. It would be more cost-effective if water can be employed as the reaction media. This paper studied hydrothermal conversion of cellulose to HMF under acidic, neutral and alkaline conditions. The results showed that, at 275–320°C and the reaction residence time of 0–30 min, the order of HMF yields followed the order of acidic, neutral and alkaline conditions. In terms of HMF purity, the order changed to neutral, acidic and alkaline conditions. Moreover, high temperatures (>300°C) and long reaction residence time had negative effects on the HMF yields in acidic and neutral solutions, mostly because of the promoted decomposition and the polymerization of HMF to levulinic acid and char, respectively. Therefore, the conditions of acidic aqueous solutions, medium range temperatures and short reaction residence time were recommended for hydrothermal conversion of cellulose to HMF. On the other hand, this study revealed that cellulose can also be converted to HMF under alkaline conditions. With the carboxylic acids produced from cellulose under alkaline conditions, the initial alkaline hydrothermal condition can gradually become acidic.