Antibiotic pollution in aqueous solutions seriously endangers the natural environment and public health. In this work, Mo-doped transition metal FeCo–Se metal aerogels (MAs) were investigated as bifunctional catalysts for the removal of sulfamethazine (SMT) in solution. The optimal Mo_0.3Fe₁Co₃–Se catalyst can remove 97.7% of SMT within 60 min (SMT content: 10 mg/L, current intensity: 10 mA/cm²). The unique porous cross-linked structure of aerogel confered the catalyst sufficient active sites and efficient mass transfer channels. For the anode, Mo_0.3Fe₁Co₃–Se MAs exhibits superior oxygen evolution reaction (OER) property, with an overpotential of only 235 mV (10 mA/cm²). Compared with Fe₁Co₃ MAs or Mo_0.3Fe₁Co₃ MAs, density functional theory (DFT) demonstrated that the better catalytic capacity of Mo_0.3Fe₁Co₃–Se MAs is attributed to the doping of Mo species and selenization lowers the energy barrier for the ^*OOH to O₂ step in the OER process. Excellent OER performance ensures the self-oxygenation in this system, avoiding the addition of air or oxygen in the traditional electro-Fenton process. For the cathode, Mo doping can lead to the lattice contraction and metallic character of CoSe₂, which is beneficial to accelerate electron transfer. The adjacent Co active sites effectively adsorb ^*OOH and inhibit the breakage of the O–O bond. Rotating ring disk electrode (RRDE) test indicated that Mo_0.3Fe₁Co₃–Se MAs has an excellent 2e⁻ ORR activity with H₂O₂ selectivity up to 88%, and the generated H₂O₂ is activated by the adjacent Fe site through heterogeneous Fenton process to generate ·OH.

High-performance electromagnetic interference (EMI) shielding materials with flexibility, excellent mechanical property, and thermal conductivity are highly desired for fifth-generation communications devices. Graphene exhibits tremendous potential due to its high electrical conductivity and unique lamellar structure. However, the construction of densified graphene structure in polymer matrix is still challenging. Herein, we develop a graphene/waterborne polyurethane (G/WPU) flexible film with densified and ordered layer-structure for using as an EMI shielding material. By virtue of the polyvinylpyrrolidone modified strategy and facile liquid phase ball-milling treatment, the graphene nanosheets can be efficiently dispersed into the WPU substrate and tightly connected between each other via internal interactions. Benefiting from the relatively low defects and densified structure of graphene, the resultant G/WPU film yields a high electrical conductivity of 1,004.5 S/m, and a tensile strength of around 48.5 MPa. As a consequence, it achieves an average EMI shielding effectiveness of over 30 dB in the X-band with a thickness of merely 0.15 mm and the value is further enhanced to 73.4 dB at 0.9 mm with a low density of 1.4 g/cm³, offering over 99.99999% shielding of incident electromagnetic waves. More importantly, this G/WPU film also exhibits a high cross-plane thermal conductivity of about 1.13 W/(m·K). Thus, this work develops a high-performance EMI shielding material with both good capacity of heat transmission, but also provides a facile strategy for designing next-generation advanced, lightweight, flexible, and multifunction shielding materials.

A novel Ni doped carbon quantum dots (Ni-CQDs) fluorescence probe was synthesized by facile electrolysis of monoatomic Ni dispersed porous carbon (Ni–N–C). The obtained Ni-CQDs showed a high quantum yield of 6.3% with the strongest excitation and emission peaks of 360 nm and 460 nm, and maintained over 90% of the maximum fluorescence intensity in a wide pH range of 3–12. The metal ions detectability of Ni-CQDs was enhanced by Ni doping and functional groups modification, and the rapid and selective detection of Fe³⁺ and Cu²⁺ ions was achieved with Ni-CQDs through dynamic and static quenching mechanism, respectively. On one hand, the energy band gap of Ni-CQDs was regulated by Ni doping, so that excited electrons in Ni-CQDs were able to transfer to Fe³⁺ easily. On the other hand, the abundant functional groups promoted the generation of static quenching complexation between Cu²⁺ and Ni-CQDs. In metal ions detection, the linear quantitation range of Fe³⁺ and Cu²⁺ were 100–1000 μM (R² = 0.9955) and 300–900 μM (R² = 0.9978), respectively. The limits of detection (LOD) were calculated as 10.17 and 7.88 μM, respectively. Moreover, the fluorescence quenched by Cu²⁺ could be recovered by EDTA²⁻ due to the destruction of the static quenching complexation. In this way, Ni-CQDs showed the ability to identify the two metal ions to a certain degree under the condition of Fe³⁺ and Cu²⁺ coexistent. This work paves the way of facile multiple metal ion detection with high sensitivity.

Despite enormous efforts in actuators, most researches are only limited to various actuation behaviors and demonstrations of soft materials. It has not yet been reported to capture and monitor its movement status in an invisible environment. Therefore, it is of great significance to develop a self-sensing and self-actuating dual-function hydrogel actuator system to realize real-time monitoring. Here, we report a bifunctional hydrogel system with self-actuating and self-monitoring abilities, which combines the functions of photothermal actuation and electrical resistance sensing into a single material. The bilayer tough conductive hydrogel synthesized by unconventional complementary concentration recombination and cryogenic freezing technique presents a dense conductive network and high-porosity structure, achieving high toughness at 190.3 kPa of tensile strength, high stretchability (164.3% strain), and the toughness dramatically (1,471.4 kJ·m⁻³). The working mechanism of the monitoring and self-sensing system is accomplished through the integrated monitoring device of surface temperature–bending angle–electron current, to solve the problem of not apperceiving actuator motion state when encountering obstacles in an invisible environment. We demonstrated for the first time a photothermal actuator’s motion of a football player and goalkeeper to finish the penalty and a soft actuator hand, which can achieve the action of sticking to grab and release under photo-thermal actuation. When connected to the control closed circuit, the actuator realized closed-loop monitoring and sensing feedback. The development of bifunctional hydrogel systems may bring new opportunities and ideas in the fields of material science, circuit technology, sensors, and mechanical engineering.

To enhance the catalytic activity by designing metal particles combined with atomically dispersed non-noble metal catalyst is a huge challenge, which yet has not been studied widely in organic reactions. Herein, we describe a simple and efficient method to synthesize Fe_xC combined with Fe single atoms anchored on the N-doped porous carbon by regulating pyrolysis temperature. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and extended X-ray absorption fine structure (EXAFS) spectroscopy corroborate the existence of atomically dispersed Fe and the coordination number between Fe and N atoms. The Fe–N–C-800 catalyst exhibits the highest catalytic activity giving the 97% yield of quinoline in dehydration of 1,2,3,4-tetrahydroquinoline (THQ) reaction at a mild condition (60 ℃, O₂ balloon), and it shows good stability with 80% isolated yield after five consecutive dehydration reactions. Moreover, density functional theory (DFT) calculations reveal that coexistence of Fe_xC and FeN_x structure exhibits high activity owing to the lowest adsorption energy of co-adsorbed O₂ and THQ and the longest N–H bond length of THQ, that is because the existence of Fe_xC induces the charges transfer. Our work may open a new route to design metal particles combined with atomically dispersed non-noble metal catalysts with high activity in organic synthesis.