Abstract:Catalysis with single-atom
catalysts (SACs) exhibits outstanding
reactivity and selectivity. However, fabrication of supports for the
single atoms with structural versatility remains a challenge to be
overcome, for further steps toward catalytic activity augmentation.
Here, we demonstrate an effective synthetic approach for a Pt SAC
stabilized on a controllable one-dimensional (1D) metal oxide nano-heterostructure
support, by trapping the single atoms at heterojunctions of a carbon
nitride/SnO2 heterostructure… Show more
“…In the XRD patterns of S-C 3 N 4 /SnO 2 -SnS 2 and S-C 3 N 4 /SnS 2 , the diffraction peaks at 15.0°, 28.2°, 32.1°, 41.9°, 50.0°and 52.5°belong to hexagonal SnS 2 (JCPDS 23-0677), while the diffraction peaks belonging to SnO 2 tend to be weaker and disappear with the amount increase of sulfur powder (Fig. S1), indicating the successful transformation of SnO 2 to SnS 2 [47,48]. The wide diffraction peak (27.4°) corresponding to the (002) reflection of C 3 N 4 can be observed in the XRD patterns of all the composites, and no XRD diffraction peaks that are ascribed to the supramolecular precursor exist (Fig.…”
Section: Characterization Of the Catalystsmentioning
Two-dimensional porous nanosheet heterostructure materials, which combine the advantages of both architecture and components, are expected to feature a significant photocatalytic performance toward CO 2 conversion into useful fuels. Herein, we provide a facile strategy for fabricating sulfur-doped C 3 N 4 porous nanosheets with embedded SnO 2 -SnS 2 nanojunctions (S-C 3 N 4 /SnO 2 -SnS 2 ) via liquid impregnation-pyrolysis and subsequent sulfidation treatment using a layered supramolecular structure as the precursor of C 3 N 4 . A hexagonal layered supramolecular structure was first prepared as the precursor of C 3 N 4 . Then Sn 4+ ions were intercalated into the supramolecular interlayers through the liquid impregnation method. The subsequent annealing treatment in air simultaneously realized the fabrication and efficient exfoliation of layered C 3 N 4 porous nanosheets. Moreover, SnO 2 nanoparticles were formed and embedded in situ in the porous C 3 N 4 nanosheets. In the following sulfidation process under a nitrogen atmosphere, sulfur powder can react with SnO 2 nanoparticles to form SnO 2 -SnS 2 nanojunctions. As expected, the exfoliation of sulfur-doped C 3 N 4 porous nanosheets and ternary heterostructure construction could be simultaneously achieved in this work. Sulfur-doped C 3 N 4 porous nanosheets with embedded SnO 2 -SnS 2 nanojunctions featured abundant active sites, enhanced visible light absorption, and efficient interfacial charge transfer. As expected, the optimized S-C 3 N 4 /SnO 2 -SnS 2 achieved a much higher gas-phase photocatalytic CO 2 reduction performance with high yields of CO (21.68 µmol g −1 h −1 ) and CH 4 (22.09 µmol g −1 h −1 ) compared with the control C 3 N 4 , C 3 N 4 / SnO 2 , and S-C 3 N 4 /SnS 2 photocatalysts. The selectivity of CH 4 reached 80.30%. Such a promising synthetic strategy can be expected to inspire the design of other robust C 3 N 4 -based porous nanosheet heterostructures for a broad range of applications. Keywords: sulfur-doped C 3 N 4 , porous nanosheets, SnO 2 -SnS 2 nanojunctions, tunable composition, CO
“…In the XRD patterns of S-C 3 N 4 /SnO 2 -SnS 2 and S-C 3 N 4 /SnS 2 , the diffraction peaks at 15.0°, 28.2°, 32.1°, 41.9°, 50.0°and 52.5°belong to hexagonal SnS 2 (JCPDS 23-0677), while the diffraction peaks belonging to SnO 2 tend to be weaker and disappear with the amount increase of sulfur powder (Fig. S1), indicating the successful transformation of SnO 2 to SnS 2 [47,48]. The wide diffraction peak (27.4°) corresponding to the (002) reflection of C 3 N 4 can be observed in the XRD patterns of all the composites, and no XRD diffraction peaks that are ascribed to the supramolecular precursor exist (Fig.…”
Section: Characterization Of the Catalystsmentioning
Two-dimensional porous nanosheet heterostructure materials, which combine the advantages of both architecture and components, are expected to feature a significant photocatalytic performance toward CO 2 conversion into useful fuels. Herein, we provide a facile strategy for fabricating sulfur-doped C 3 N 4 porous nanosheets with embedded SnO 2 -SnS 2 nanojunctions (S-C 3 N 4 /SnO 2 -SnS 2 ) via liquid impregnation-pyrolysis and subsequent sulfidation treatment using a layered supramolecular structure as the precursor of C 3 N 4 . A hexagonal layered supramolecular structure was first prepared as the precursor of C 3 N 4 . Then Sn 4+ ions were intercalated into the supramolecular interlayers through the liquid impregnation method. The subsequent annealing treatment in air simultaneously realized the fabrication and efficient exfoliation of layered C 3 N 4 porous nanosheets. Moreover, SnO 2 nanoparticles were formed and embedded in situ in the porous C 3 N 4 nanosheets. In the following sulfidation process under a nitrogen atmosphere, sulfur powder can react with SnO 2 nanoparticles to form SnO 2 -SnS 2 nanojunctions. As expected, the exfoliation of sulfur-doped C 3 N 4 porous nanosheets and ternary heterostructure construction could be simultaneously achieved in this work. Sulfur-doped C 3 N 4 porous nanosheets with embedded SnO 2 -SnS 2 nanojunctions featured abundant active sites, enhanced visible light absorption, and efficient interfacial charge transfer. As expected, the optimized S-C 3 N 4 /SnO 2 -SnS 2 achieved a much higher gas-phase photocatalytic CO 2 reduction performance with high yields of CO (21.68 µmol g −1 h −1 ) and CH 4 (22.09 µmol g −1 h −1 ) compared with the control C 3 N 4 , C 3 N 4 / SnO 2 , and S-C 3 N 4 /SnS 2 photocatalysts. The selectivity of CH 4 reached 80.30%. Such a promising synthetic strategy can be expected to inspire the design of other robust C 3 N 4 -based porous nanosheet heterostructures for a broad range of applications. Keywords: sulfur-doped C 3 N 4 , porous nanosheets, SnO 2 -SnS 2 nanojunctions, tunable composition, CO
“…[7,8] In addition, thermal degradation of the sensing layer and the agglomeration of metal catalysts could both degrade the sensor performance, compromising its reliability in long-term operations. [9,10] Moreover, the brittleness of oxides limits the scope of utilization from flexible and wearable devices, which are key aspects for consumer applications in the immediate future. To this end, it is necessary to develop an effective design strategy which integrates nanostructured oxide layers with a flexible polymer substrate as an underlying layer [11,12] and a molecular sieving layer for selective gas filtration.…”
Though highly promising as powerful gas sensors, oxide semiconductor chemiresistors have low surface reactivity, which limits their selectivity, sensitivity, and reaction kinetics, particularly at room temperature (RT) operation. It is proposed that a hybrid design involving the nanostructuring of oxides and passivation with selective gas filtration layers can potentially overcome the issues with surface activity. Herein, unique bi‐stacked heterogeneous layers are introduced; that is, nanostructured oxides covered by conformal nanoporous gas filters, on ultrahigh‐density nanofiber (NF) yarns via sputter deposition with indium tin oxide (ITO) and subsequent self‐assembly of zeolitic imidazolate framework (ZIF‐8) nanocrystals. The NF yarn composed of ZIF‐8‐coated ITO films can offer heightened surface activity at RT because of high porosity, large surface area, and effective screening of interfering gases. As a case study, the hybrid sensor demonstrated remarkable sensing performances characterized by high NO selectivity, fast response/recovery kinetics (>60‐fold improvement), and large responses (12.8‐fold improvement @ 1 ppm) in comparison with pristine yarn@ITO, especially under highly humid conditions. Molecular modeling reveals an increased penetration ratio of NO over O2 to the ITO surface, indicating that NO oxidation is reliably prevented and that the secondary adsorption sites provided by the ZIF‐8 facilitate the adsorption/desorption of NO, both to and from ITO.
“…Copyright 2021, Wiley‐VCH. (E) Schematic illustration of the synthesis route of single Pt atoms in carbon nitride/SnO 2 heterostructure. Reproduced with permission 289. Copyright 2020, American Chemical Society…”
Section: Strategies For Fabrication Of Smacsmentioning
confidence: 99%
“…Moreover, compared to the Pt/TiO 2 catalyst, Pt/CeO x ‐TiO 2 delivered 15.1 times greater specific mass activity for CO oxidation, which showed the catalytic superiority of heterointerface‐anchored SMACs. Besides, as shown in Figure 7e, carbon nitride/SnO 2 heterostructure was employed as the support to capture the Pt SAs at the heterojunctions via electrospinning and subsequent calcinating treatment 289 . The heterojunction‐anchored Pt SAs exhibited remarkably stable catalytic behavior.…”
Section: Strategies For Fabrication Of Smacsmentioning
Single-metal-atom catalysts (SMACs) with the merits of maximum atom utilization, peculiar electronic structure, and adjustable coordination environment, have emerged as the rising stars. They are not only regarded as the promising electrocatalysts, but also show unconventionally excellent alkali storage, thus enabling them for energy devices. In this work, we review the up-to-date progress of single metal atom catalysts including the detailed synthetic strategies and all sorts of applications in energy storage and conversion. In addition, we also discuss intrinsic catalytic effects, degradation mechanism, modulation approaches, support structure design, current challenges, and potential development trends. This work may shed light on developing high-performance SMACs using a variety of strategies for catalytic and energy applications.
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