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2024 Volume 43 Issue 3
2024, 43(3): 100209
doi: 10.1016/j.cjsc.2023.100209
Abstract:
Porous materials have garnered significant attention in recent years. Understanding the intrinsic relationship between their structures and properties requires precise knowledge of their atomic structures. Single-crystal X-ray diffraction (SCXRD) has traditionally been the primary method for elucidating such structures, but it demands large, high-quality crystals, often exceeding 5 μm in size. The growth of these crystals can be a time-consuming process, especially for one- and two-dimensional materials. To explore structures at the nanoscale, MicroED (microcrystal electron diffraction (ED)) offers unprecedented insights into the realm of nanomaterials. This revolutionary technique enables researchers to uncover intricate details within nanoscale structures, promising to reshape our fundamental understanding of materials. In this review, we delve into the applications of MicroED in the study of various porous materials, including zeolites, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs). We emphasize the pivotal role of MicroED in nanomaterial characterization, enabling precise crystallographic analysis and phase identification.
Porous materials have garnered significant attention in recent years. Understanding the intrinsic relationship between their structures and properties requires precise knowledge of their atomic structures. Single-crystal X-ray diffraction (SCXRD) has traditionally been the primary method for elucidating such structures, but it demands large, high-quality crystals, often exceeding 5 μm in size. The growth of these crystals can be a time-consuming process, especially for one- and two-dimensional materials. To explore structures at the nanoscale, MicroED (microcrystal electron diffraction (ED)) offers unprecedented insights into the realm of nanomaterials. This revolutionary technique enables researchers to uncover intricate details within nanoscale structures, promising to reshape our fundamental understanding of materials. In this review, we delve into the applications of MicroED in the study of various porous materials, including zeolites, metal-organic frameworks (MOFs), and covalent organic frameworks (COFs). We emphasize the pivotal role of MicroED in nanomaterial characterization, enabling precise crystallographic analysis and phase identification.
2024, 43(3): 100240
doi: 10.1016/j.cjsc.2024.100240
Abstract:
Porphyrin and phthalocyanine compounds belong to a class of large and aromatic macrocyclic compounds. Owing to their unique structures and electronic properties, they have found widespread applications in optoelectronic devices. In recent years, the doping of porphyrins and phthalocyanines into perovskite solar cells (PSCs) has emerged as an effective strategy to enhance device performance and stability. This doping strategy enables the modulation of perovskite film crystallization and surface defects, thereby improving charge transfer and enhancing the photo-conversion efficiency. As sensitizers, porphyrins and phthalocyanines absorb light in the visible and near-infrared spectral ranges, providing an advantage to the light absorption characteristics of PSCs. Additionally, their roles in interface modification and defect repair contribute to the long-term stability of the devices. The central metal of porphyrin can also adsorb ions and prevent the migration of harmful ions. This review summarizes the recent progress in the research on porphyrin and phthalocyanine-doped PSCs, emphasizing their potential value in enhancing optoelectronic performance, increasing stability and expanding the application scope of these devices.
Porphyrin and phthalocyanine compounds belong to a class of large and aromatic macrocyclic compounds. Owing to their unique structures and electronic properties, they have found widespread applications in optoelectronic devices. In recent years, the doping of porphyrins and phthalocyanines into perovskite solar cells (PSCs) has emerged as an effective strategy to enhance device performance and stability. This doping strategy enables the modulation of perovskite film crystallization and surface defects, thereby improving charge transfer and enhancing the photo-conversion efficiency. As sensitizers, porphyrins and phthalocyanines absorb light in the visible and near-infrared spectral ranges, providing an advantage to the light absorption characteristics of PSCs. Additionally, their roles in interface modification and defect repair contribute to the long-term stability of the devices. The central metal of porphyrin can also adsorb ions and prevent the migration of harmful ions. This review summarizes the recent progress in the research on porphyrin and phthalocyanine-doped PSCs, emphasizing their potential value in enhancing optoelectronic performance, increasing stability and expanding the application scope of these devices.
2024, 43(3): 100244
doi: 10.1016/j.cjsc.2024.100244
Abstract:
Achieving high heat-resisting room temperature phosphorescence (RTP) performance and robust white emission from pure small molecules is a meaningful but challenging work. Herein, a simple donor-acceptor (D-A) molecule, 9-(1H-benzotriazol-1-ylmethyl)-9H-carbazole (CzBtrz), was investigated. This simple molecule not only exhibits multiple emissions including white light, thermally activated delayed fluorescence (TADF) and ultralong RTP with a lifetime of 988.54 ms at 545 nm, but also shows superhigh heat-resisting phosphorescence property which can maintain stability in a large temperature region from 77 to 350 K (ΔT = 273 K), exceeding those of other RTP systems. Meanwhile, this molecule shows the time-evolved dynamic RTP. The experimental and theoretical analyses from CzBtrz crystal demonstrate that the intramolecular charge transfer (ICT) interaction and molecular stacking play an important role in the generation of RTP. Therefore, this work provides an efficient strategy to design ultrahigh heat-resistant RTP, ultralong RTP and single-phased white-light emitting materials.
Achieving high heat-resisting room temperature phosphorescence (RTP) performance and robust white emission from pure small molecules is a meaningful but challenging work. Herein, a simple donor-acceptor (D-A) molecule, 9-(1H-benzotriazol-1-ylmethyl)-9H-carbazole (CzBtrz), was investigated. This simple molecule not only exhibits multiple emissions including white light, thermally activated delayed fluorescence (TADF) and ultralong RTP with a lifetime of 988.54 ms at 545 nm, but also shows superhigh heat-resisting phosphorescence property which can maintain stability in a large temperature region from 77 to 350 K (ΔT = 273 K), exceeding those of other RTP systems. Meanwhile, this molecule shows the time-evolved dynamic RTP. The experimental and theoretical analyses from CzBtrz crystal demonstrate that the intramolecular charge transfer (ICT) interaction and molecular stacking play an important role in the generation of RTP. Therefore, this work provides an efficient strategy to design ultrahigh heat-resistant RTP, ultralong RTP and single-phased white-light emitting materials.
2024, 43(3): 100245
doi: 10.1016/j.cjsc.2024.100245
Abstract:
Sunlight-induced photocatalytic carbon dioxide (CO2) reduction to energy-rich chemicals by metal-free polymeric carbon nitride (CN) semiconductor is a promising tactic for sustained solar fuel production. However, the reaction efficiency of CO2 photoreduction is restrained seriously by the rapid recombination of photogenerated carriers on CN polymer. Herein, we incorporate 2-aminopyridine molecule with strong electron-withdrawing group into the skeleton edge of CN layers through a facile one-pot thermal polymerization strategy using urea as the precursor, which renders a modified carbon nitride (ACN) with extended optical harvesting, abundant nitrogen defects and ultrathin nanosheet structure. Consequently, the ACN photocatalyst with desirable structural features attains enhanced separation and migration of photoexcited charge carriers. Under visible light irradiation with Co(bpy)32+ as a cocatalyst, the optimized ACN sample manifests a high CO2 deoxygnative reduction activity and high stability, providing a CO yielding rate of 17 μmol h-1, which is significantly higher than that of pristine CN. The key intermediates engaged in CO2 photoreduction reaction are determined by the in situ diffuse reflectance infrared Fourier transform spectroscopy, which sponsors the construction of the possible photocatalytic CO2 reduction mechanism on ACN nanosheets.
Sunlight-induced photocatalytic carbon dioxide (CO2) reduction to energy-rich chemicals by metal-free polymeric carbon nitride (CN) semiconductor is a promising tactic for sustained solar fuel production. However, the reaction efficiency of CO2 photoreduction is restrained seriously by the rapid recombination of photogenerated carriers on CN polymer. Herein, we incorporate 2-aminopyridine molecule with strong electron-withdrawing group into the skeleton edge of CN layers through a facile one-pot thermal polymerization strategy using urea as the precursor, which renders a modified carbon nitride (ACN) with extended optical harvesting, abundant nitrogen defects and ultrathin nanosheet structure. Consequently, the ACN photocatalyst with desirable structural features attains enhanced separation and migration of photoexcited charge carriers. Under visible light irradiation with Co(bpy)32+ as a cocatalyst, the optimized ACN sample manifests a high CO2 deoxygnative reduction activity and high stability, providing a CO yielding rate of 17 μmol h-1, which is significantly higher than that of pristine CN. The key intermediates engaged in CO2 photoreduction reaction are determined by the in situ diffuse reflectance infrared Fourier transform spectroscopy, which sponsors the construction of the possible photocatalytic CO2 reduction mechanism on ACN nanosheets.
2024, 43(3): 100249
doi: 10.1016/j.cjsc.2024.100249
Abstract:
Herein, we introduce a redox conjugated covalent organic polymer (p-HATN, HATN = hexaazatrinaphthylene) anode bearing HATN species for long-lifespan aqueous alkaline and acidic batteries. The p-HATN features intriguing superhydrophilicity and unique wide pH adaptability, while the conjugated network and amorphous cross-linked structure further endow p-HATN with improved electron transport, facile ion diffusion and superior acid-alkali tolerability. As a result, p-HATN exhibits fast surface-controlled redox activity and superior stability for K+ and H+ ions storage with remarkable capacity retentions in three-electrode cells (88% capacity retention in 13 M KOH over 30000 cycles; nearly 100% capacity retention in 0.5 M H2SO4 over 54000 cycles). Moreover, the assembled p-HATN//Ni(OH)2 cell with 13 M KOH and p-HATN//PbO2 cell with 0.5 M H2SO4 also achieve capacity retentions of 83% retention over 55000 cycles and 92% over 15000 cycles, respectively, outperforming most similar systems. This work sheds light on the rational design of advanced polymer anodes for long-lifespan alkaline and acidic batteries.
Herein, we introduce a redox conjugated covalent organic polymer (p-HATN, HATN = hexaazatrinaphthylene) anode bearing HATN species for long-lifespan aqueous alkaline and acidic batteries. The p-HATN features intriguing superhydrophilicity and unique wide pH adaptability, while the conjugated network and amorphous cross-linked structure further endow p-HATN with improved electron transport, facile ion diffusion and superior acid-alkali tolerability. As a result, p-HATN exhibits fast surface-controlled redox activity and superior stability for K+ and H+ ions storage with remarkable capacity retentions in three-electrode cells (88% capacity retention in 13 M KOH over 30000 cycles; nearly 100% capacity retention in 0.5 M H2SO4 over 54000 cycles). Moreover, the assembled p-HATN//Ni(OH)2 cell with 13 M KOH and p-HATN//PbO2 cell with 0.5 M H2SO4 also achieve capacity retentions of 83% retention over 55000 cycles and 92% over 15000 cycles, respectively, outperforming most similar systems. This work sheds light on the rational design of advanced polymer anodes for long-lifespan alkaline and acidic batteries.
2024, 43(3): 100251
doi: 10.1016/j.cjsc.2024.100251
Abstract:
The need for high-performance and cost-effective gas sensors in industrial and domestic settings has led to advancements in gas sensors based on metal-organic frameworks (MOFs). However, challenges remain in the design and synthesis of MOFs with customized structure and affinity toward targeted gases and their integration onto miniaturized electronic devices. The deliberate design of MOFs with desired characteristics is hindered by limited understanding of the interactions between MOFs and analytes. Furthermore, there is a lack of customization of relevant MOF-based sensors with salient sensing performance and their integration into sensor arrays to align with different application scenarios. The combination of machine learning or artificial intelligence (AI) with gas sensors also represents a promising avenue for future research. Herein, we provide a mini-review of recent accomplishments in MOF-based gas sensors, covering materials design and device integration. The challenges of miniaturization and building smart sensing systems with anomaly detection, self-calibration, and lifetime prediction are also discussed.
The need for high-performance and cost-effective gas sensors in industrial and domestic settings has led to advancements in gas sensors based on metal-organic frameworks (MOFs). However, challenges remain in the design and synthesis of MOFs with customized structure and affinity toward targeted gases and their integration onto miniaturized electronic devices. The deliberate design of MOFs with desired characteristics is hindered by limited understanding of the interactions between MOFs and analytes. Furthermore, there is a lack of customization of relevant MOF-based sensors with salient sensing performance and their integration into sensor arrays to align with different application scenarios. The combination of machine learning or artificial intelligence (AI) with gas sensors also represents a promising avenue for future research. Herein, we provide a mini-review of recent accomplishments in MOF-based gas sensors, covering materials design and device integration. The challenges of miniaturization and building smart sensing systems with anomaly detection, self-calibration, and lifetime prediction are also discussed.
Te-doped Fe3O4 flower enabling low overpotential cycling of Li-CO2 batteries at high current density
2024, 43(3): 100253
doi: 10.1016/j.cjsc.2024.100253
Abstract:
Li-CO2 batteries (LCBs) suffer from high overpotentials caused by sluggish CO2 reaction kinetics. This work designs a Te-doped Fe3O4 (Te-Fe3O4) flower-like microsphere catalyst to lower the overpotential and improve the reversibility of LCBs. Experimental results reveal that Te doping modifies the electronic structure of Fe3O4 and reduces the overpotential. The stable Te-O bond between Te and C2O42- could effectively inhibit the disproportionation reaction of the latter, enabling the Te-Fe3O4 cathodes to exhibit a remarkable capacity (9485 mAh g-1) and a long cycling life (155 cycles) with an overpotential of 1.21 V and an energy efficiency of about 80% at a high current density (2000 mA g-1). Through the interaction between Te and Li2C2O4 to inhibit the disproportionation reaction, this work successfully achieves long-term cycling of LCBs with low overpotential at high current density.
Li-CO2 batteries (LCBs) suffer from high overpotentials caused by sluggish CO2 reaction kinetics. This work designs a Te-doped Fe3O4 (Te-Fe3O4) flower-like microsphere catalyst to lower the overpotential and improve the reversibility of LCBs. Experimental results reveal that Te doping modifies the electronic structure of Fe3O4 and reduces the overpotential. The stable Te-O bond between Te and C2O42- could effectively inhibit the disproportionation reaction of the latter, enabling the Te-Fe3O4 cathodes to exhibit a remarkable capacity (9485 mAh g-1) and a long cycling life (155 cycles) with an overpotential of 1.21 V and an energy efficiency of about 80% at a high current density (2000 mA g-1). Through the interaction between Te and Li2C2O4 to inhibit the disproportionation reaction, this work successfully achieves long-term cycling of LCBs with low overpotential at high current density.
2024, 43(3): 100255
doi: 10.1016/j.cjsc.2024.100255
Abstract:
In summary, Cu-based bimetallic catalysts exhibit outstanding activity and selectivity in CO2RR, attributed to the distinctive electronic structure and adsorption energy of key intermediates. Furthermore, the leaching and re-deposition mechanism of the amphoteric metal (Zn, Al), influenced by the strong alkaline electrolyte and reduction potentials, has been demonstrated to play a crucial role in the performance of Cu-based bimetallic catalysts. In conclusion, this study not only introduces an effective strategy for designing efficient Cu-based catalysts for CO2RR towards C2+ products but also provides new insights into the surface reconstruction of amphoteric metal-doped Cu2O catalysts.
In summary, Cu-based bimetallic catalysts exhibit outstanding activity and selectivity in CO2RR, attributed to the distinctive electronic structure and adsorption energy of key intermediates. Furthermore, the leaching and re-deposition mechanism of the amphoteric metal (Zn, Al), influenced by the strong alkaline electrolyte and reduction potentials, has been demonstrated to play a crucial role in the performance of Cu-based bimetallic catalysts. In conclusion, this study not only introduces an effective strategy for designing efficient Cu-based catalysts for CO2RR towards C2+ products but also provides new insights into the surface reconstruction of amphoteric metal-doped Cu2O catalysts.
2024, 43(3): 100268
doi: 10.1016/j.cjsc.2024.100268
Abstract:
Five new semiconductors Pb5Sb12+xBi6-xSe32 (x = 0, 1, 2, 3, and 4) have been synthesized for the first time, which adopt pavonite-type structure and crystallize in monoclinic C2/m space group. The crystal structure is composed of two different types of polyhedral slabs. Slab-I is a galena-like structure motif that forms with [MSe6] (M = Pb, Sb, and Bi) octahedra and slab-II contains one octahedral [MSe6] block and paired squared pyramids [MSe5]. Pb5Sb12+xBi6-xSe32 exhibits n-type semiconductor behaviors and the remarkable Seebeck coefficient from -64.1 μV K-1 for x = 0 sample to -242 μV K-1 for x = 4 sample at 300 K. Moreover, the Pb5Sb12Bi6Se32 has the highest carrier concentration of 1.35 × 1020 cm-3 in pavonite-type materials. The complex compositions, mixed occupancies of the cations, and quasi-two-dimensional structure lead to the low lattice thermal conductivity (κlat) less than 0.48 W m-1 K-1 from 300 to 723 K, at which Pb5Sb16Bi2Se32 especially shows the ultralow value of 0.25 W m-1 K-1. As a result, the thermoelectric figure of merit, ZT ∼0.34 at 723 K, is obtained for the intrinsic Pb5Sb12Bi6Se32.
Five new semiconductors Pb5Sb12+xBi6-xSe32 (x = 0, 1, 2, 3, and 4) have been synthesized for the first time, which adopt pavonite-type structure and crystallize in monoclinic C2/m space group. The crystal structure is composed of two different types of polyhedral slabs. Slab-I is a galena-like structure motif that forms with [MSe6] (M = Pb, Sb, and Bi) octahedra and slab-II contains one octahedral [MSe6] block and paired squared pyramids [MSe5]. Pb5Sb12+xBi6-xSe32 exhibits n-type semiconductor behaviors and the remarkable Seebeck coefficient from -64.1 μV K-1 for x = 0 sample to -242 μV K-1 for x = 4 sample at 300 K. Moreover, the Pb5Sb12Bi6Se32 has the highest carrier concentration of 1.35 × 1020 cm-3 in pavonite-type materials. The complex compositions, mixed occupancies of the cations, and quasi-two-dimensional structure lead to the low lattice thermal conductivity (κlat) less than 0.48 W m-1 K-1 from 300 to 723 K, at which Pb5Sb16Bi2Se32 especially shows the ultralow value of 0.25 W m-1 K-1. As a result, the thermoelectric figure of merit, ZT ∼0.34 at 723 K, is obtained for the intrinsic Pb5Sb12Bi6Se32.
