Introduction of Protonated Sites on Exfoliated, Large-Area Sheets of Hexagonal Boron Nitride

Jasuja, Kabeer; Ayinde, Kayum; Wilson, Christina L.; Behura, Sanjay K.; Ikenbbery, Myles A.; Moore, David S.; Hohn, Keith L.; Berry, Vikas

doi:10.1021/acsnano.8b03651

Cited by 50 publications

(46 citation statements)

References 50 publications

(78 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The as‐prepared BNNS ( Figure 2 a) are homogenously and steadily dispersed in isopropanol solvent. As shown in Figure b, the extinction spectrum of the diluted dispersion exhibits a peak at 204 nm, which means that the band gap E g of the so‐obtained BNNS is ≈6.1 eV ( E g = hc/λ g , where λ g is the wavelength, h is the Planck constant, and c is the speed of light) . This value is the same as intrinsic layered h‐BN (hexagonal boron nitride), different from the functionalized ones, indicating the BNNS used inheritate the good insulating properties from the layered precursor after the exfoliation process .…”

Section: Resultsmentioning

confidence: 96%

“…BNNS with high insulation are prepared by exfoliation. [21] This value is the same as intrinsic layered h-BN (hexagonal boron nitride), different from the functionalized ones, indicating the BNNS used inheritate the good insulating properties from the layered precursor after the exfoliation process. As shown in Figure 2b, the extinction spectrum of the diluted dispersion exhibits a peak at 204 nm, which means that the band gap E g of the so-obtained BNNS is ≈6.1 eV (E g = hc/λ g , where λ g is the wavelength, h is the Planck constant, and c is the speed of light).…”

Section: Preparation and Characterization Of Gradient-structured Pbpnsmentioning

confidence: 95%

See 1 more Smart Citation

Polymer Nanocomposites with Interpenetrating Gradient Structure Exhibiting Ultrahigh Discharge Efficiency and Energy Density

Jiang

Shen

Cai

et al. 2019

Advanced Energy Materials

143

114

View full text Add to dashboard Cite

Poly(vinylidene fluoride) (PVDF) based polymer nanocomposites with high‐permittivity nanofillers exhibit outstanding dielectric energy storage performance due to their high dielectric permittivities and breakdown strength. However, their discharge efficiency is relatively low (usually lower than 70%), which limits their practical applications. Here, polymer nanocomposites with a novel interpenetrating gradient structure are designed and demonstrated by cofilling a PVDF matrix with barium zirconate titanate nanofibers and hexagonal boron nitride nanosheets via modified nonequilibrium processing. The interpenetrating gradient structure is highly effective in breaking the trade‐off between discharge energy density and efficiency of the corresponding nanocomposite, as indicated by the concomitantly enhanced discharge energy density (U e ≈ 23.4 J cm−3) and discharge efficiency (η ≈ 83%). The superior performance is primarily attributed to the rational distribution of nanofillers in the polymer matrix, which raises the height of the potential barrier for charge injection at the dielectric/electrode interface, suppresses electric conduction and contributes to enhanced apparent breakdown strength. Meanwhile, the gradient configuration allows higher volume fraction of high‐permittivity nanofillers without compromising the breakdown strength, leading to higher electric polarization compared with the random configuration. This work provides new opportunities to PVDF‐based polymer nanocomposites with high energy density and discharge efficiency for capacitive energy storage applications.

show abstract

Section: Resultsmentioning

confidence: 96%

Section: Preparation and Characterization Of Gradient-structured Pbpnsmentioning

confidence: 95%

Polymer Nanocomposites with Interpenetrating Gradient Structure Exhibiting Ultrahigh Discharge Efficiency and Energy Density

Jiang

Shen

Cai

et al. 2019

Advanced Energy Materials

143

114

View full text Add to dashboard Cite

show abstract

“…This is contingent on proper synthesis of bulk materials, and their exfoliation into dispersible, monolayered and defect‐free 2D nanosheets for membrane fabrication . On this basis, efficient surface modification methods should be available for the nanosheets so that desirable transporting characteristics can be obtained in resultant laminates . 2) Membrane Assembly : The established assembling methods are imperfect in creating laminar membranes with highly interlocked and parallel layers .…”

Section: Discussionmentioning

confidence: 99%

2D Laminar Membranes for Selective Water and Ion Transport

Kang

Xia

Wang

et al. 2019

Adv Funct Materials

243

148

View full text Add to dashboard Cite

energy storage and conversion devices, [26][27][28] as outlined in recent reviews (Figure 1, left). [29] Behind these applications lie a fundamental question: how water and ion transport are controlled in the laminar structure to obtain desired selectivity. A comprehensive summary of structure-transport relation is thereby imperative to understand and optimize membrane selective performance, but is so far lacking. In such context, our review aims to fill this gap by discussing: 1) how 2D materials with specific physicochemical features are assembled into laminar membranes; 2) most importantly, how membrane structure, and its response to external impacts, can tune mass transport (herein, water and ions); 3) how these transport mechanisms translate into selectivity in applications, and into future design of high-performance laminar membranes. Unsolved problems and emerging challenges around these topics are then concluded. We note that the knowledge summarized here can also, at least partly, assist the understanding of the selective gas, liquid, and micromolecule transport through laminar membranes, which are gaining considerable attention as well. [30][31][32] Transition Metal Carbides and/or Nitrides (MXene): MXene nanosheets are etched and delaminated from parent bulk MAX to M n+1 X n T x (e.g., Ti 3 C 2 T x ), and have thus several atom sublayers. [39] While M and X are early transition metal

show abstract

“…Moreover, the ultrathin structure also enables facile integration with other materials to form heterostructures or hybrids to further regulate the electronic structure and charge separation, leading to enhanced photocatalytic performances . Exfoliation of layered synthetic polymers is a formidable route for the scalable and efficient production of ultrathin 2D polymer nanosheets . Unfortunately, direct exfoliation of 2D polymers still leads to low yields (normally the yield is <15%), which impedes further applications of ultrathin 2D polymer nanosheets .…”

Section: Introductionmentioning

confidence: 99%

Protonation‐Assisted Exfoliation of N‐Containing 2D Conjugated Polymers

Zhang

Luo

Zheng

et al. 2019

Small

View full text Add to dashboard Cite

natural incorporation into the conjugated polymer frameworks mainly comprised of carbon atoms. [8][9][10][11] Consequently, the optoelectronic properties can be conveniently tailored in N-containing 2D conjugated polymers through different synthetic routes using different organic building blocks.On the other hand, compared to bulk 2D polymers, ultrathin nanosheets (<10 nm in thickness) are highly favorable for photocatalytic applications as the ultrathin feature offers several unique advantages in photocatalysis including more exposed active sites, enhanced photoresponsiveness and efficient charge separation. [12][13][14][15] Moreover, the ultrathin structure also enables facile integration with other materials to form heterostructures or hybrids to further regulate the electronic structure and charge separation, leading to enhanced photocatalytic performances. [16][17][18][19] Exfoliation of layered synthetic polymers is a formidable route for the scalable and efficient production of ultrathin 2D polymer nanosheets. [20][21][22][23] Unfortunately, direct exfoliation of 2D polymers still leads to low yields (normally the yield is <15%), which impedes further applications of ultrathin 2D polymer nanosheets. [24] To circumvent this problem, a more reliable exfoliation route is highly desired.The key to improving the exfoliation yield is to either weaken the interlayer interactions in layered polymers or enhance the affinity between the polymer surfaces and the dispersion media. [25][26][27] To tailor the interlayer interactions, guest substances such as concentrated H 2 SO 4 are intercalated into the interlayers of 2D polymers. [28] Although this method can achieve high yields, sometimes the chemical structures of the Ultrathin 2D conjugated polymer nanosheets are an emerging class of photocatalysts for solar-to-chemical energy conversion. Until now, the majority of ultrathin 2D polymer photocatalysts are produced through exfoliation of layered polymers. Unfortunately, it still remains a great challenge to exfoliate layered polymers into ultrathin nanosheets with high yields. In this work, a liquid-phase protonation-assisted exfoliation is demonstrated to enable remarkably improved exfoliation yields of various 2D N-containing conjugated polymers such as g-C 3 N 4 , C 2 N, and aza-CMP. The exfoliation yields are only 2-15% in pure water whereas they can be substantially improved to 41-56% in 12 m HCl. The exfoliated ultrathin nanosheets possess average thicknesses less than 5 nm and can be easily dispersed in aqueous solutions. More importantly, the exfoliated nanosheets exhibit significantly enhanced photocatalytic activity toward photocatalytic water splitting compared to their bulk counterparts. Further characterizations and computational calculations reveal that protonation of the heterocyclic nitrogen sites in the conjugated polymer frameworks can lead to strong hydrogen bonding between the polymer surfaces and water molecules, resulting in facilitated exfoliation of polymers into the liquid phase. This study ...

show abstract

Introduction of Protonated Sites on Exfoliated, Large-Area Sheets of Hexagonal Boron Nitride

Cited by 50 publications

References 50 publications

Polymer Nanocomposites with Interpenetrating Gradient Structure Exhibiting Ultrahigh Discharge Efficiency and Energy Density

Polymer Nanocomposites with Interpenetrating Gradient Structure Exhibiting Ultrahigh Discharge Efficiency and Energy Density

2D Laminar Membranes for Selective Water and Ion Transport

Protonation‐Assisted Exfoliation of N‐Containing 2D Conjugated Polymers

Contact Info

Product

Resources

About