Electrocatalytic C-N coupling for urea synthesis represents a sustainable alternative to conventional production methods. Copper clusters have demonstrated remarkable catalytic activity in both CO2 reduction and nitrate (NO3-) reduction reactions. However, on a single copper cluster, intense competition between different substrate reactions significantly constrains the ability to execute multistep co-reduction reactions. Herein, we report the first complementary heterocopper-cluster-based covalent metal-organic framework (Cu4Cu3-CMOF), constructed by covalently linking two structurally and catalytically distinct copper cluster units, which preserves the inherent catalytic properties of each cluster. Compared with single-copper-cluster-based CMOFs, the heteronuclear Cu4Cu3-CMOF exhibits superior catalytic activity for the efficient conversion of CO2 and NO3-into urea, owing to the separation of catalytic role and their synergistic collaboration within the integrated framework. It achieves a urea yield of 22.3 mmol g-1 h-1 with a faradaic efficiency of 41.6%, ranking among the highest performances reported for metal-cluster-based electrocatalysts. Experimental and theoretical calculation results confirm that the orderly connected hetero-copperclusters play a crucial role in separately activating CO2 and NO3-into key intermediates that promote C-N bond formation. This study establishes a novel design model for high-performance, metal-cluster-based catalysts, showing great potential for urea synthesis.
Narrow bandgap polymers with short-wavelength infrared (SWIR, 1400-3000 nm) light absorption are rare but promising for optical and optoelectronic applications. A general strategy for designing narrow bandgap polymers involves the synthesis of donor-acceptor (D-A) type conjugated polymers in which donor and acceptor units are alternately copolymerized. In this study, we propose atomic-level D-A type conjugated polymers as a new molecular design strategy to develop conjugated polymers with SWIR photoresponse. The resonant N-B-N bond in 4,4 '-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) induces spatial separation between the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO), that is, on atomic-level D-A characteristics. Therefore, BODIPY was used as a building block to construct atomic-level D-A type conjugated polymers by connecting units via the alpha-positions and introducing electron-deficient substituents at the meso-positions. As a result, these polymers exhibit a maximum absorption wavelength of 1612 nm and an onset absorption wavelength of 2010 nm. When employed as photoactive layers in SWIR photodetectors, they enable a photoresponse wavelength up to 2000 nm with a responsivity of 1.4 & times; 104 A W-1 and a specific detectivity of 2.3 & times; 1010 Jones at 1550 nm. This work not only provides a new design strategy for SWIR semiconductors but also demonstrates their application in highperformance SWIR photodetectors.
Aerogels, macroscopic assemblies of low-dimensional nanomaterials in three-dimensional space, serve as a critical bridge to translate the extraordinary physicochemical properties of such nanoscale building blocks into practical macroscopic applications. However, their highly exposed reaction surfaces render them susceptible to drastic chemical and multiphase interfacial fluctuations during synthesis, hindering uniform, efficient nanoscale-to-mesoscale design and synthesis, thus limiting broader practical use. Herein, we report a solid-acid-mediated interfacial slow-release regulation strategy for silica aerogel hydrophobization, enabling 10-times faster ambient drying synthesis [diameter >3 cm, thickness similar to 1 cm, peak transmittance 96% between 380 and 760 nm, <14 h vs >145 h (hours) for state-ofthe-art strategy] of centimeter-scale monoliths. In-situ Fourier transform infrared, CT characterizations and molecular dynamics simulations reveal that local acid concentration regulation ensures uniform hydrophobic group grafting and preserves the integrity of the aerogel network. Aerogels exhibit ultralow thermal conductivity (0.034 W/m & centerdot; K at 50 degrees C) and high compressive strength (806 kPa at complete failure). A solar-thermal device based on the aerogels achieves 165 degrees C heat-collection temperature and 79.5 W/m(2) power density under 1 kW/m(2) solar radiation, outperforming most reported photothermalthermoelectric devices under equivalent conditions. This work establishes a conceptually-new interfacial regulation paradigm for construction of high-performance inorganic aerogels and other low dimensional inorganic materials.
