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1.
Small ; : e2311267, 2024 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-38534041

RESUMEN

The controllable construction of complex metal-organic coordination polymers (CPs) merits untold scientific and technological potential, yet remains a grand challenge of one-step construction and modulating simultaneously valence states of metals and topological morphology. Here, a thiocyanuric acid (TCA)-triggered strategy is presented to one-step rapid synthesis a double-crystalline Prussian blue analogue hetero-superstructure (PBA-hs) that comprises a Co3[Fe(CN)6]2 cube overcoated with a KCo[Fe(CN)6] shell, followed by eight self-assembled small cubes on vertices. Unlike common directing surfactants, TCA not only acts as a trigger for the fast growth of KCo[Fe(CN)6] on the Co3[Fe(CN)6]2 phase resulting in a PBA-on-PBA hetero-superstructure, but also serves as a flange-like bridge between them. By combining experiments with simulations, a deprotonation-induced electron transfer (DIET) mechanism is proposed for formation of second phase in PBA-hs, differing from thermally and photo-induced electron transfer processes. To prove utility, the calcined PBA-hs exhibits enhanced oxygen evolution reaction performance. This work provides a new method to design of novel CPs for enriching chemistry and material science. This work offers a practical approach to design novel CPs for enriching chemistry and material science.

2.
Small ; 19(30): e2302906, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-37183269

RESUMEN

The hollow sandwich core-shell micro-nanomaterials are widely used in materials, chemistry, and medicine, but their fabrication, particularly for transition metal phosphides (TMPs), remains a great challenge. Herein, a general synthesis strategy is presented for binary TMPs hollow sandwich heterostructures with vertically interconnected nanosheets on the inside and outside surfaces of polyhedron FeCoPx /C, demonstrated by a variety of transition metals (including Co, Fe, Cd, Mn, Cu, Cr, and Ni). Density functional theory (DFT) calculation reveals the process and universal mechanism of layered double hydroxide (LDH) growth on Prussian blue analog (PBA) surface in detail for the first time, which provides the theoretical foundations for feasibility and rationality of the synthesis strategy. This unique structure exhibits a vertical nanosheet-shell-vertical nanosheet configuration combining the advantages of sandwich, hollow and vertical heterostructures, effectively achieving their synergistic effect. As a proof-of-concept of their applications, the CoNiPx @FeCoPx /C@CoNiPx hollow sandwich polyhedron architectures (representative samples) show excellent catalytic performance for the oxygen evolution reaction (OER) in alkaline electrolytes. This work provides a general method for constructing hollow-sandwich micro-nanostructures, which provides more ideas and directions for design of micro-nano materials with special geometric topology.

3.
J Adv Nurs ; 77(4): 2033-2049, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33523488

RESUMEN

AIMS: To evaluate the effectiveness of the hospital-family holistic care model based on the theory of 'Timing It Right' in caregivers of patients with permanent enterostomy. DESIGN: A prospective randomized controlled trial. METHODS: One hundred and twenty-five caregivers of patients with permanent enterostomy were recruited from 1 May 2017-31 August 2019. They were randomized into either intervention group (N = 62) or control group (N = 63). The control group received routine care and follow-up, while the intervention group received routine care, follow-up, and hospital-family holistic care intervention based on 'Timing It Right'. The care ability, psychological distress, and life quality of the caregivers were evaluated between the groups before the intervention, at discharge, and 3 and 6 months after discharge. RESULTS: One hundred and eleven caregivers completed the study (88.8%). At 3 and 6 months after discharge, the care ability and life quality in the intervention group were significantly better than those in the control group (t = 8.506/9.783, t = 22.652/26.179, p < 0.05) based on the t tests, and the psychological distress was lower than that in the control group. The ostomy adaptability of the control group was significantly lower than that in the intervention group (p < 0.001) based on the t tests, and the χ2 test showed that ostomy complication was more than that in the intervention group (23.81% vs. 12.90% and 34.92% vs. 19.35%; p < 0.05) at 3 and 6 months after discharge. The interaction between time and group showed that the effect of time factor varied with the group and the four evaluation indexes in the intervention group gradually improved with the extension of the observation time and were better than those in the control group based on generalized estimating equation model. CONCLUSION: The hospital-family holistic care model based on 'Timing It Right' can effectively improve the care ability of caregivers of patients with permanent enterostomy, reduce psychological distress, and improve the quality of life. IMPACT: The caregivers of patients with permanent enterostomy showed dynamic changes in their care experience and needs at different stages of the disease. The hospital-family holistic care intervention strategy based on 'Timing It Right' can effectively improve the caregiver's care ability, alleviate psychological distress, and improve the quality of life. Additionally, improving the patients' stoma adaptability and reducing the incidence of complications related to ostomy.


Asunto(s)
Cuidadores , Enterostomía , Hospitales , Humanos , Estudios Prospectivos , Calidad de Vida
4.
Phys Chem Chem Phys ; 22(5): 3037-3047, 2020 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-31960006

RESUMEN

The energetic alignment of band edges at the interface plays a central role in determining the properties and applications of two-dimensional (2D) van der Waals (vdW) heterostructures. Generally, three conventional heterojunction types (type-I, type-II, and type-III) have widely been investigated and used in diverse fields. Unconventional band alignments (type-IV, type-V, and type-VI) are, however, hitherto unreported in the vdW heterostructures. We find that 2D binary semiconductors composed of group IV-V elements manifest a similar electronic structure, offering in principle the possibility of designing heterostructures with novel band alignments due to the hybridization of band-edge states. We first show here that a 2D SiAs/GeP heterostructure exhibits a type-VI band alignment, which is induced by the interlayer pz orbital hybridization, and a transition of band alignment from type-VI to type-V occurs when strain or electric field is applied over a critical value. The unconventional band alignments and their transition natures enable broad application of these vdW heterostructures in special opto-electronic devices and energy conversion.

5.
J Clin Nurs ; 29(13-14): 2196-2208, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-31970830

RESUMEN

AIMS AND OBJECTIVES: To explore the effects of hospital-family holistic care model based on 'Timing It Right' on the health outcome of patients with permanent colostomy. BACKGROUND: Colorectal cancer is a common malignant tumour of digestive system, which seriously threatens human life and health. Colostomy is one of the main treatments for colorectal cancer, which effectively improves the 5-year survival rate of patients. However, the postoperative psychological and physiological rehabilitation nursing is still faced with great challenges due to the change of body image and defecation pathway caused by colostomy. METHODS: A randomised controlled trial was conducted, and 119 patients with permanent enterostomy were randomly divided into two groups, with 60 cases in the intervention group and 59 cases in the control group. The intervention group received routine care follow-up and hospital-family holistic care intervention based on 'Timing It Right', while the control group received routine care and follow-up. The resilience, self-care ability, complications and life quality of patients with permanent enterostomy were compared between two groups before intervention, at discharge, 3 months and 6 months after discharge. CONSORT checklist was applied as the reporting guideline for this study (see Appendix S1). RESULTS: A total of 108 patients with permanent enterostomy completed the study (90.76%). At 3 months and 6 months after discharge, the resilience and quality of life in the intervention group were significantly better than those in the control group (t = 4.158 vs. 7.406, t = 4.933 vs. 8.611, p < .05), while the complications in the intervention group were significantly lower than that in the control group (25.5% vs. 41.51%, 14.45% vs. 30.19%; p < .05). The self-care ability of the intervention group was significantly better than that in the control group (t = 1.543 vs. 3.656 vs. 6.273, p < .05) at discharge, 3 months and 6 months after discharge. The interaction between time and grouping showed that the effect of time factor varied with the grouping. After intervention, there were significant differences in psychological resilience, self-care ability, complications and quality of life between the two groups at different observation points (p < .01). The three evaluation indices of intervention group increased with the migration of observation time points and were significantly better than those of control group, especially the quality of life (84.35 ± 4.25 vs. 60.45 ± 8.42, p < .01). CONCLUSIONS: The hospital-family holistic care model based on 'Timing It Right' can effectively improve the psychological resilience, self-care ability and quality of life; reduce complications; and improve the health outcomes of patients with permanent enterostomy. RELEVANCE TO CLINICAL PRACTICE: Patients with permanent enterostomy have different needs for nursing care at different stages of the disease, and they are dynamically changing. The hospital-family holistic care model based on 'Timing It Right' can effectively improve the health outcomes of patients with permanent enterostomy, which is worthy of clinical application.


Asunto(s)
Colostomía/psicología , Enfermería Holística/métodos , Calidad de Vida , Anciano , Neoplasias Colorrectales/cirugía , Colostomía/enfermería , Femenino , Humanos , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Resiliencia Psicológica , Autocuidado
6.
Chemphyschem ; 19(3): 291-299, 2018 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-29178167

RESUMEN

A high light-absorption coefficient and long-range hot-carrier transport of hybrid organic-inorganic perovskites give huge potential to their composites in solar energy conversion and environmental protection. Understanding interfacial interactions and their effects are paramount for designing perovskite-based heterostructures with desirable properties. Herein, we systematically investigated the interfacial interactions in monolayer and few-layer SnS/CH3 NH3 PbI3 heterostructures and their effects on the electronic and optical properties of these structures by density functional theory. It was found that the interfacial interactions in SnS/CH3 NH3 PbI3 heterostructures were van der Waals (vdW) interactions, and they were found to be insensitive to the layer number of 2D SnS sheets. Interestingly, although their band gap decreased upon increasing the layer number of SnS, the near-gap electronic states and optical absorption spectra of these heterostructures were found to be strikingly similar. This feature was determined to be critical for the design of 2D layered SnS-based heterostructures. Strong absorption in the ultraviolet and visible-light regions, type II staggered band alignment at the interface, and few-layer SnS as an active co-catalyst make 2D SnS/CH3 NH3 PbI3 heterostructures promising candidates for photocatalysis, photodetectors, and solar energy harvesting and conversion. These results provide first insight into the nature of interfacial interactions and are useful for designing hybrid organic-inorganic perovskite-based devices with novel properties.

7.
J Nanosci Nanotechnol ; 18(8): 5502-5510, 2018 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-29458603

RESUMEN

Elimination of pollutants from water is one of the greatest challenges in resolving global environmental issues. Herein, we report a high-surface-area mesoporous g-C3N4 nanosheet with remarkable high adsorption capacity and photocatalytic performance, which is prepared through directly polycondensation of urea followed by a consecutive one-step thermal exfoliation strategy. This one-pot method to prepare mesoporous g-C3N4 nanosheet is facile and rapid in comparison with others. The superior adsorption capacity of the fabricated mesoporous g-C3N4 nanostructures is demonstrated by a model organic pollutant-methylene blue (MB), which is up to 72.2 mg/g, about 6 times as that of the largest value of various g-C3N4 adsorbents reported so far. Moreover, this kind of porous g-C3N4 nanosheet exhibits high photocatalytic activity to MB and phenol degradation. Particularly, the regenerated samples show excellent performance of pollutant removal after consecutive adsorption/degradation cycles. Therefore, this mesoporous g-C3N4 nanosheet may be an attractive robust metal-free material with great promise for organic pollutant elimination.

8.
Phys Chem Chem Phys ; 19(11): 7955-7963, 2017 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-28262896

RESUMEN

Understanding the interfacial interaction is of paramount importance for rationally designing carbon nanomaterial-based hybrids with optimal performance for electronics, optoelectronics, sensing, advanced energy conversion and storage. Here, we firstly reveal that both covalent and noncovalent interactions simultaneously exist in carbon nanotube (CNT)/Ag3PO4 hybrids by studying systematically the electronic and optical properties to elucidate the mechanism of their enhanced photocatalytic performance. Metallic CNT(9,0) may chemically or physically interact with the Ag3PO4(100) surface depending on its relative orientations, whereas semiconducting CNT(10,0) can only noncovalently functionalize Ag3PO4. The C-Ag bond in the covalently bonded hybrid and type-II, staggered, band alignment in noncovalent hybrids lead to a robust separation of photoexcited charge carriers between two constituents, thus enhancing the photocatalytic activity. The small band gap makes the CNT/Ag3PO4 hybrids absorb sunlight from the ultraviolet to infrared region. Moreover, CNTs are not only effective sensitizers, but also highly active co-catalysts in hybrids. The results can be rationalized by the available experiments, thereby partly resolving a debate on the interpretation of the experimental results, and paving the way for developing highly efficient carbon-based nanophotocatalysts.

9.
Phys Chem Chem Phys ; 18(4): 2878-86, 2016 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-26733154

RESUMEN

The coupling of carbon nanomaterials with semiconductor photocatalysts is a promising route to improve their photocatalytic performance. Herein, density functional theory was used to investigate the electronic structure, charge transfer, photocatalytic activity, and stability in a series of hybrid fullerene (C20, Li@C20, C26, Li@C26)/Ag3PO4(100) composites. When a Li atom is incorporated in fullerene, the adsorption energies significantly increase, although the change of interface distance is negligibly small due to the weak interface interaction. The charge transfer between constituents decreases with the C atom number of fullerene. Compared to pure Ag3PO4, the band gap of the composites is smaller, which enhances the visible-light absorption and photoinduced electron transfer. Most importantly, a type-II, staggered band alignment could be obtained in the C26-Ag3PO4(Li@C26-Ag3PO4) interface, leading to significantly reduced charge recombination and thus enhanced photocatalytic activity. These results reveal that fullerene modification would be an effective strategy to improve the photocatalytic performance of Ag3PO4 semiconductor photocatalysts.

10.
Phys Chem Chem Phys ; 18(48): 33094-33102, 2016 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-27886313

RESUMEN

Recent experiments have shown that the photocatalytic activity of g-C3N4 can be greatly enhanced by C60 modification, however, a fundamental understanding of its mechanistic operation is still lacking. Using first-principles calculations, the interfacial effects of C60/g-C3N4 nanocomposites on the electronic properties, charge transfer and optical response have been explored in detail. For different stacking patterns, the two constituents are always linked by van der Waals (vdW) forces without any exception, and form type-II heterojunctions in most cases. The valence band maximum and conduction band minimum of these heterostructures are dominated by the unsaturated nitrogen (N2) atoms and C60 molecule, respectively, which strongly interact with each other, resulting in strong charge transfer between the two involved constituents and an obvious bending of the g-C3N4 sheets. The unsaturated N2 atoms included in the interfaces have a significant influence on promoting the photocatalytic performance, while the existence of saturated nitrogen (N1 and N3) atoms lying in the interfaces will weaken the interfacial interactions between C60 molecules and the g-C3N4 monolayers. Moreover, the sensitive optical response and satisfactory type-II band alignment clearly show that the C60/g-C3N4 heterostructure is an outstanding photocatalyst for hydrogen production. We proposed a deep insight (the role of nitrogen) into understanding the improved photocatalytic ability of the C60/g-C3N4 nanocomposites, which may contribute to the rational design of both C60/g-C3N4 and g-C3N4-based nanocomposite photocatalysts.

11.
J Colloid Interface Sci ; 667: 44-53, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38615622

RESUMEN

The construction of high-asymmetrical structures demonstrates significant potential in improving the functionality and distinctness of nanomaterials, but remains a considerable challenge. Herein, we develop a one-pot method to fabricate regioselective super-assembly of Prussian blue analogue (PBA) -- a PBA anisotropic structure (PBA-AS) decorated with epitaxial modules--using a step-by-step epitaxial growth on a rapidly self-assembled cubic substrate guided by thiocyanuric acid (TCA) molecules. The epitaxial growth units manifest as diverse geometric shapes, which are predominantly concentrated on the {100}, {111}, or {100}+{111} crystal plane of the cubic substrate. The crystal plane and morphology of epitaxial module can be regulated by changing the TCA concentration and reaction temperature, enabling a high level of controllability over specific assembly sites and structures. To illustrate the advantage of the asymmetrical structure, phosphated PBA-AS demonstrates improved performance in the oxygen evolution reaction compared to simple phosphated PBA nanocube. This method offers valuable insights for designing asymmetrical nanomaterials with intricate architectures and versatile functionalities.

12.
Nanoscale Adv ; 6(2): 638-647, 2024 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-38235104

RESUMEN

The rational design of electrocatalysts with well-designed compositions and structures for the oxygen evolution reaction (OER) is promising and challenging. Herein, we developed a novel strategy - a one-step double-cation etching sedimentation equilibrium strategy - to synthesize amorphous hollow Fe-Co-Ni layered double hydroxide nanocages with an outer surface of vertically interconnected ultrathin nanosheets (Fe-Co-Ni-LDH), which primarily depends on the in situ etching sedimentation equilibrium of the template interface. This unique vertical nanosheet-shell hierarchical nanostructure possesses enhanced charge transfer, increased active sites, and favorable kinetics during electrolysis, resulting in superb electrocatalytic performance for the oxygen evolution reaction (OER). Specifically, the Fe-Co-Ni-LDH nanocages exhibited remarkable OER activity in alkaline electrolytes and achieved a current density of 100 mA cm-2 at a low overpotential of 272 mV with excellent stability. This powerful strategy provides a profound molecular-level insight into the control of the morphology and composition of 2D layered materials.

13.
J Phys Chem Lett ; 15(9): 2428-2435, 2024 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-38394780

RESUMEN

Catalytic performance of single-atom catalysts (SACs) relies fundamentally on the electronic nature and local coordination environment of the active site. Here, based on a machine-learning (ML)-aided density functional theory (DFT) method, we reveal that the intrinsic dipole in Janus materials has a significant impact on the catalytic activity of SACs, using 2D γ-phosphorus carbide (γ-PC) as a model system. Specifically, a local dipole around the active site is a key degree to tune the catalytic activity and can be used as an important descriptor with a high feature importance of 17.1% in predicting the difference of adsorption free energy (ΔGO* - ΔGOH*) to assess the activity of the oxygen evolution reaction. As a result, the catalytic performance of SACs can be tuned by an intrinsic dipole, in stark contrast to those external stimuli strategies previously used. These results suggest that dipole engineering and the revolutionary DFT-ML hybrid scheme are novel approaches for designing high-performance catalysts.

14.
Adv Sci (Weinh) ; 10(32): e2303321, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37814357

RESUMEN

The oxygen evolution reaction (OER) activity of transition metal (TM)-based (oxy)hydroxide is dominated by the number and nature of surface active sites, which are generally considered to be TM atoms occupying less than half of surface sites, with most being inactive oxygen atoms. Herein, based on an in situ competing growth strategy of bimetallic ions and OH- ions, a facile one-step method is proposed to modulate oxygen defects in NiFe-layered double hydroxide (NiFe-LDH)/FeOOH heterostructure, which may trigger the single lattice oxygen mechanism (sLOM). Interestingly, by only varying the addition of H2 O2 , one can simultaneously regulate the concentration of oxygen defects, the valence of metal sites, and the ratio of components. The proper oxygen defects promote synergy between the adsorbate evolution mechanism (AEM, metal redox chemistry) and sLOM (oxygen redox chemistry) of OER in NiFe-based (oxy)hydroxide, practically maximizing the use of surface TM and oxygen atoms as active sites. Consequently, the optimal NiFe-LDH/FeOOH heterostructure outperforms the reported non-noble OER catalysts in electrocatalytic activity, with an overpotential of 177 mV to deliver a current density of 20 mA cm-2 and high stability. The novel strategy exemplifies a facile and versatile approach to designing highly active TM-LDH-based OER electrocatalysts for energy and environmental applications.

15.
ACS Nano ; 17(4): 3465-3482, 2023 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-36763083

RESUMEN

Photoelectrocatalytic performance of a system is fundamentally determined by the full absorption of sunlight and high utilization of photoexcited carriers, but efficiency of the latter is largely limited by inefficient charge transfer from the absorber to reactive sites. Here, we propose to construct directional charge transfer channels in a monolithically integrated electrode, taking carbon dots/carbon nitride (CCN) nanotubes and FeOOH/FeCo layered double hydroxide (FFC) nanosheets as a representative, to boost the photoassisted overall water splitting performance. Detailed experimental investigations and DFT calculations demonstrate that the interfacial C-O-Fe bonds between CCN and FFC act as charge transfer channels, facilitating the directional migration of the photogenerated carriers between CCN and FFC surfaces. Moreover, the in situ oxidized Fe/Co species by photogenerated holes trigger lattice oxygen activation, realizing the construction of the Fe-Co dual-site as the catalytic center and efficiently lowering the barrier energy for water oxidation. As a result, the CCN@FFC electrode shows multiple functionalities in photoelectrocatalysis: only a low overpotential of 68 mV, 182 mV, and 1.435 V is required to deliver 10 mA cm-2 current densities for the photoassisted HER, OER, and overall water splitting, respectively. This directional charge transfer modulation strategy may facilitate the design of highly active and cost-effective multifunctional catalysts for energy conversion and storage.

16.
Zhejiang Da Xue Xue Bao Yi Xue Ban ; 41(2): 222-8, 2012 03.
Artículo en Zh | MEDLINE | ID: mdl-22499524

RESUMEN

Channels from the TRP superfamily have essential roles in a wide variety of sensory transductions, especially in mechano-sensation, such as hearing, touch and mechanical pain. TRP channels are also implicated in major channelopathies, including deafness, chronic pain, autosomal dominant polycystic kidney disease (ADPKD) and ventricular hypertrophy. As the leading candidates for mechano-sensitive channels, some TRP channels appear to be mechano-receptor, which can be activated by mechanical forces directly, such as C. elegans TRPN homolog TRP-4; whereas others may act as signal modulators, receiving and amplifying signals indirectly. This review is to introduce the function of TRPs in mechano-sensory transduction and to discuss the underlying molecular mechanisms.


Asunto(s)
Sensación/fisiología , Canales de Potencial de Receptor Transitorio/fisiología , Animales , Humanos , Conducción Nerviosa , Transducción de Señal , Canales de Potencial de Receptor Transitorio/metabolismo
17.
Nanoscale Res Lett ; 15(1): 180, 2020 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-32955632

RESUMEN

Two-dimensional (2D) transition metal dichalcogenides with intrinsically passivated surfaces are promising candidates for ultrathin optoelectronic devices that their performance is strongly affected by the contact with the metallic electrodes. Herein, first-principle calculations are used to construct and investigate the electronic and interfacial properties of 2D MoTe2 in contact with a graphene electrode by taking full advantage of them. The obtained results reveal that the electronic properties of graphene and MoTe2 layers are well preserved in heterostructures due to the weak van der Waals interlayer interaction, and the Fermi level moves toward the conduction band minimum of MoTe2 layer thus forming an n type Schottky contact at the interface. More interestingly, the Schottky barrier height and contact types in the graphene-MoTe2 heterostructure can be effectively tuned by biaxial strain and external electric field, which can transform the heterostructure from an n type Schottky contact to a p type one or to Ohmic contact. This work provides a deeper insight look for tuning the contact types and effective strategies to design high performance MoTe2-based Schottky electronic nanodevices.

18.
Nanomicro Lett ; 12(1): 52, 2020 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-34138281

RESUMEN

Self-assembled nanostructure arrays integrating the advantages of the intrinsic characters of nanostructure as well as the array stability are appealing in advanced materials. However, the precise bottom-up synthesis of nanostructure arrays without templates or substrates is quite challenging because of the general occurrence of homogeneous nucleation and the difficult manipulation of noncovalent interactions. Herein, we first report the precisely manipulated synthesis of well-defined louver-like P-doped carbon nitride nanowire arrays (L-PCN) via a supramolecular self-assembly method by regulating the noncovalent interactions through hydrogen bond. With this strategy, CN nanowires align in the outer frame with the separation and spatial location achieving ultrastability and outstanding photoelectricity properties. Significantly, this self-assembly L-PCN exhibits a superior visible light-driven hydrogen evolution activity of 1872.9 µmol h-1 g-1, rendering a ~ 25.6-fold enhancement compared to bulk CN, and high photostability. Moreover, an apparent quantum efficiency of 6.93% is achieved for hydrogen evolution at 420 ± 15 nm. The experimental results and first-principles calculations demonstrate that the remarkable enhancement of photocatalytic activity of L-PCN can be attributed to the synergetic effect of structural topology and dopant. These findings suggest that we are able to design particular hierarchical nanostructures with desirable performance using hydrogen-bond engineering.

19.
Nanoscale ; 12(10): 6037-6046, 2020 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-32129406

RESUMEN

Efficient spatial charge separation and transfer that are critical factors for solar energy conversion primarily depend on the energetic alignment of the band edges at interfaces in heterojunctions. Herein, we first report that constructing a 0D/0D type-II(T-II)/T-II heterojunction is an effective strategy to ingeniously achieve long-range charge separation by taking a ternary heterojunction of TiO2 and graphitic carbon nitride (g-C3N4) as a proof-of-concept. Incorporating g-C3N4 quantum dots (QCN), as the third component, into the commercial P25 composed of anatase (a-TiO2) and rutile (r-TiO2) can be realized via simply mixing the commercially available Degussa P25 and QCN solution followed by heat treatment. The strong coupling and matching band structures among a-TiO2, r-TiO2 and QCN result in the construction of novel T-II/T-II heterojunctions, which would promote the spatial separation and transfer of photogenerated electrons and holes. Moreover, QCN plays a key role in reinforcing light absorption. Particularly, the unique 0D/0D architecture possesses the advantages of abundant active sites for the photocatalytic reaction. As a result, the optimized QCN/a-TiO2/r-TiO2 heterojunctions exhibit enhanced photocatalytic H2 and O2 evolution, especially the hydrogen evolution rate (49.3 µmol h-1) is 11.7 times that of bare P25 under visible light irradiation, and sufficient catalytic stability as evidenced by the recycling experiments. The remarkably enhanced photocatalytic activity can be attributed to the synergistic effects of the energy level alignment at interfaces, the dimensionality and component of the heterojunctions. This work provides a stepping stone towards the design of novel heterojunctions for photocatalytic water splitting.

20.
Adv Mater ; 32(11): e1906015, 2020 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-32027058

RESUMEN

Developing low-cost, highly efficient, and durable electrocatalysts for oxygen evolution reaction (OER) is essential for the practical application of electrochemical water splitting. Herein, it is discovered that organic small molecule (hexabromobenzene, HBB) can activate commercial transition metal (Ni, Fe, and NiFe) foam by directly evolving metal nanomeshes embedded in graphene-like films (M-NM@G) through a facile Br-induced solid-phase migration process. Systematic investigations indicate that HBB can conformally generate graphene-like network on bulk metal foam substrate via the cleavage of CBr bonds and the formation of CC linkage. Simultaneously, the cleaved CBr fragments can efficiently extract metal atoms from bulk substrate, in situ producing transition metal nanomeshes embedded in the graphene-like films. As a result, such functional nanostructure can serve as an efficient OER electrocatalyst with a low overpotential and excellent long-term stability. Specifically, the overpotential at 100 mA cm-2 is only 208 mV for NiFe-NM@G, ranking the top-tier OER electrocatalysts. This work demonstrates an intriguing general strategy for directly transforming bulk transition metals into nanostructured functional electrocatalysts via the interaction with organic small molecules, opening up opportunities for bridging the application of organic small molecules in energy technologies.

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