Wearable thermoelectric devices show promises to generate electricity in a ubiquitous, unintermittent and noiseless way for on-body applications. Threedimensional thermoelectric textiles (TETs) outperform other types in smart textiles owing to their out-of-plane thermoelectric generation and good structural conformability with fabrics. Yet, there has been lack of efficient strategies in scalable manufacture of TETs for sustainably powering electronics. Here, we fabricate organic spacer fabric shaped TETs by knitting carbon nanotube yarn based segmented thermoelectric yarn in large scale. Combing finite element analysis with experimental evaluation, we elucidate that the fabric structure significantly influences the power generation. The optimally designed TET with good wearability and stability shows high output power density of 51.5 mW/m 2 and high specific power of 173.3 µW/(g·K) at ∆T= 47.5 K. The promising on-body applications of the TET in directly and continuously powering electronics for healthcare and environmental monitoring is fully demonstrated. This work will broaden the research vision and provide new routines for developing high-performance and large-scale TETs toward practical applications.
Low-cost, non-noble-metal electrocatalysts are required for direct methanol fuel cells,b ut their development has been hindered by limited activity,high onset potential, low conductivity,a nd poor durability.Asurface electronic structure tuning strategy is presented, which involves doping of aforeign oxophilic post-transition metal onto transition metal aerogels to achieve an on-noble-metal aerogel Ni 97 Bi 3 with unprecedented electrocatalytic activity and durability in methanol oxidation. Trace amounts of Bi are atomically dispersed on the surface of the Ni 97 Bi 3 aerogel, which leads to an optimum shift of the d-band center of Ni, large compressive strain of Bi, and greatly increased conductivity of the aerogel. The electrocatalyst is endowed with abundant active sites, efficient electron and mass transfer,r esistance to CO poisoning, and outstanding performance in methanol oxidation. This work sheds light on the design of high-performance non-noblemetal electrocatalysts.
Insufficient catalytic activity and stability and high cost are the barriers for Pt‐based electrocatalysts in wide practical applications. Herein, a hierarchically porous PtNi nanoframe/N‐doped graphene aerogel (PtNiNF‐NGA) electrocatalyst with outstanding performance toward methanol oxidation reaction (MOR) in acid electrolyte has been developed via facile tert‐butanol‐assisted structure reconfiguration. The ensemble of high‐alloying‐degree‐modulated electronic structure and correspondingly the optimum MOR reaction pathway, the structure superiorities of hierarchical porosity, thin edges, Pt‐rich corners, and the anchoring effect of the NGA, endow the PtNiNF‐NGA with both prominent electrocatalytic activity and stability. The mass and specific activity (1647 mA mgPt−1, 3.8 mA cm−2) of the PtNiNF‐NGA are 5.8 and 7.8 times higher than those of commercial Pt/C. It exhibits exceptional stability under a 5‐hour chronoamperometry test and 2200‐cycle cyclic voltammetry scanning.
Nanogap plasmonic structures, which can strongly enhance electromagnetic fields, enable widespread applications in surface-enhanced Raman spectroscopy (SERS) sensing. Although the directed self-assembly strategy has been adopted for the fabrication of micro/nanostructures on open surfaces, fabrication of nanogap plasmonic structures on complex substrates or at designated locations still remains a grand challenge. Here, a switchable self-assembly method is developed to manufacture 3D nanogap plasmonic structures by combining supercritical drying and capillary-force driven selfassembly (CFSA) of micropillars fabricated by laser printing. The polymer pillars can stay upright during solvent development via supercritical drying, and then can form the nanogap after metal coating and subsequent CFSA. Due to the excellent flexibility of this method, diverse patterned plasmonic nanogap structures can be fabricated on planar or nonplanar substrates for SERS. The measured SERS signals of different patterned nanogaps in fluidic environment show a maximum enhancement factor ≈8 × 10 7 . Such nanostructures in microchannels also allow localized sensing for anticancer drugs (doxorubicin). Resulting from the marriage of top-down and self-assembly techniques, this method provides a facile, effective, and controllable approach for creating nanogap enabled SERS devices in fluidic channels, and hence can advance applications in precision medicine.
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