Honeycomb Framework Research Articles

Honeycomb‐Structured IrOx Foam Platelets as the Building Block of Anode Catalyst Layer in PEM Water Electrolyzer

AbstractAchieving robust long‐term durability with high catalytic activity at low iridium loading remains one of great challenges for proton exchange membrane water electrolyzer (PEMWE). Herein, we report the low‐temperature synthesis of iridium oxide foam platelets comprising edge‐sharing IrO6 octahedral honeycomb framework, and demonstrate the structural advantages of this material for multilevel tuning of anodic catalyst layer across atomic‐to‐microscopic scales for PEMWE. The integration of IrO6 octahedral honeycomb framework, foam‐like texture and platelet morphology into a single material system assures the generation and exposure of highly active and stable iridium catalytic sites for the oxygen evolution reaction (OER), while facilitating the reduction of both mass transport loss and electronic resistance of catalyst layer. As a proof of concept, the membrane electrode assembly in single‐cell PEMWE based on honeycomb‐structured IrOx foam platelets, with a low iridium loading (~0.3 mgIr/cm2), is demonstrated to exhibit high catalytic activity at ampere‐level current densities and to remain stable for more than 2000 hours.

Honeycomb-Structured IrOx Foam Platelets as the Building Block of Anode Catalyst Layer in PEM Water Electrolyzer.

Achieving robust long-term durability with high catalytic activity at low iridium loading remains one of great challenges for proton exchange membrane water electrolyzer (PEMWE). Herein, we report the low-temperature synthesis of iridium oxide foam platelets comprising edge-sharing IrO6 octahedral honeycomb framework, and demonstrate the structural advantages of this material for multilevel tuning of anodic catalyst layer across atomic-to-microscopic scales for PEMWE. The integration of IrO6 octahedral honeycomb framework, foam-like texture and platelet morphology into a single material system assures the generation and exposure of highly active and stable iridium catalytic sites for the oxygen evolution reaction (OER), while facilitating the reduction of both mass transport loss and electronic resistance of catalyst layer. As a proof of concept, the membrane electrode assembly in single-cell PEMWE based on honeycomb-structured IrOx foam platelets, with a low iridium loading (~0.3 mgIr/cm2), is demonstrated to exhibit high catalytic activity at ampere-level current densities and to remain stable for more than 2000 hours.

Continuous adaptation of conversation aids for uterine fibroids treatment options in a four-year multi-center implementation project

BackgroundFibroids are non-cancerous uterine growths that can cause symptoms impacting quality of life. The breadth of treatment options allows for patient-centered preference. While conversation aids are known to facilitate shared decision making, the implementation of these aids for uterine fibroids treatments is limited. We aimed to develop two end-user-acceptable uterine fibroids conversation aids for an implementation project. Our second aim was to outline the adaptations that were made to the conversation aids as implementation occurred.MethodsWe used a multi-phase user-centered participatory approach to develop a text-based and picture-enhanced conversation aid for uterine fibroids. We conducted a focus group with project stakeholders and user-testing interviews with eligible individuals with symptomatic uterine fibroids. We analyzed the results of the user-testing interviews using Morville’s Honeycomb framework. Spanish translations of the conversation aids occurred in parallel with the English iterations. We documented the continuous adaptations of the conversation aids that occurred during the project using an expanded framework for reporting adaptations and modifications to evidence-based interventions (FRAME).ResultsThe first iteration of the conversation aids was developed in December 2018. Focus group participants (n = 6) appreciated the brevity of the tools and suggested changes to the bar graphs and illustrations used in the picture-enhanced version. User-testing with interview participants (n = 9) found that both conversation aids were satisfactory, with minor changes suggested. However, during implementation, significant changes were suggested by patients, other stakeholders, and participating clinicians when they reviewed the content. The most significant changes required the addition or deletion of information about treatment options as newer research was published or as novel interventions were introduced into clinical practice.ConclusionsThis multi-year project revealed the necessity of continuously adapting the uterine fibroids conversation aids so they remain acceptable in an implementation and sustainability context. Therefore, it is important to seek regular user feedback and plan for the need to undertake updates and revisions to conversation aids if they are going to be acceptable for clinical use.

Two-dimensional Ti3C2Tx anchored on three-dimensional SiC honeycomb framework for efficient and cyclic photocatalytic degradation of organic pollutants

The excellent recyclability of SiC foam renders it an ideal catalyst in the field of photocatalytic degradation, however to further improve its photocatalytic efficiency remains a major challenge in current research. In this regard, a honeycomb-like porous SiC foam was successfully constructed through freeze-drying and polymer-to-ceramic derivation method, with two-dimensional Ti3C2Tx nanosheets anchored on its three-dimensional framework. Their photocatalytic performances were evaluated by the degradation of methylene blue (MB) under visible-light irradiation. All Ti3C2Tx/SiC hybrid foams show superior photocatalytic degradation capability compared with SiC foam, with a highest removal rate (adsorption and degradation) reaching 94.4% for TSF-4, denoting an increasement of 50.4%. Even after five cycles, the removal rate remained at 91.4% with only a slightly loss of 3%, suggesting its excellent recycling performance. These desirable results stem from the unique structural design, in which the porous structure facilitates the contact between catalyst and pollutant, while the Ti3C2Tx/SiC heterojunction promotes effective separation of photogenerated carriers. This work paves the way for the development of lightweight, efficient and easily recyclable photocatalyst for wastewater purification.

A novel metamaterial with instantaneously sign-switchable coefficient of thermal expansion and Poisson's ratio

Most materials expand when heated and contract when cooled. In contrast, negative thermal expansion materials exhibit the opposite behavior. In this paper, we present a metamaterial that expands both when heated and cooled. The unit cell configuration is crafted by embedding two isosceles triangular structures composed of high thermal expansion materials within a re-entrant hexagonal honeycomb framework. Initially, the bases of the two isosceles triangles are in contact. The metamaterial exhibits two deformation states under different external loads. Analytical formulas for the equivalent parameters were derived based on classical beam theory within the regime of small deformation. Finite element simulations were conducted to validate the accuracy of these analytical formulas. The influence of geometric parameters on the metamaterial is discussed in detail. The results demonstrate that the metamaterial can exhibit excellent multi-functional properties within a small range of deformation, including instantaneous sign-variable coefficients of thermal expansion and Poisson's ratios, along with significantly distinct tensile and compressive stiffnesses. This metamaterial consistently exhibits expansive characteristics regardless of variations in ambient temperature. Additionally, the material always expands laterally regardless of the sign of uniaxial loads. Based on these properties, the metamaterial can be applied to fasteners in the aerospace industry that require permanent locking, ensuring stability in various temperature and mechanical load conditions.

Development of a patient-centered transition program for stroke survivors and their informal caregivers, combining case-management and access to an online information platform: A user-centered design approach.

During the hospital-to-home transition, stroke survivors and their caregivers face a significant lack of support and information which impacts their psychosocial recovery. We aimed to co-design a program combining individual support by a trained case-manager (dedicated professional providing individual support) and an online information platform to address needs of stroke survivors and caregivers. A two-step methodology was used. The first step followed a "user-centered design" approach during four workshops with stroke survivors, caregivers, and healthcare professionals to develop the platform and define the case-manager profile. The second step was a usability test of the platform following a Think Aloud method with patients and caregivers. The workshops and interviews were analyzed following a qualitative thematic analysis. The analysis of Think Aloud interviews was based on User Experience Honeycomb framework by Morville. Eight participants attended the workshops: two patients, two caregivers, three nurses, and a general practitioner. Activities, training, and skills of the case-manager were defined according to stroke survivors and caregivers needs. Name, graphics, navigation, and content of the platform were developed with the participants, a developer and a graphic designer. The usability of the platform was tested with 5 patients and 5 caregivers. The Think Aloud confirmed satisfaction with graphics and content but a need for improvement regarding the navigability. An update of the platform was conducted in order to answer the needs expressed by participants. We developed, with a participatory approach, a patient-centered transition program, which will be evaluated in a randomized controlled trial.

Metal-driven folding and assembly of a minimal β-sheet into a 3D-porous honeycomb framework.

In contrast to short helical peptides, constrained peptides, and foldamers, the design and fabrication of crystalline 3D frameworks from the β-sheet peptides are rare because of their high self-aggregation propensity to form 1D architectures. Herein, we demonstrate the formation of a 3D porous honeycomb framework through the silver coordination of a minimal β-sheet forming a peptide having terminal metal coordinated 4- and 3-pyridyl ligands.

Supramolecular Self-assemblies of inverted cucurbit[6]uril with 1,5-pentanediamine

In this study, single crystal X-ray diffraction and 1H NMR spectroscopy were used to examine the interaction of the guest 1,5-pentanediamine with inverted cucurbit[6]uril (iQ[6]) in the presence of [ZnCl4]2− anion. The results show that [ZnCl4]2− and [Zn(H2O)Cl3]− anions form a honeycomb framework structure, and iQ[6] forms a 1:1 complex with 1,5-pentanediamine. Inverted cucurbit[6]uril forms molecular chains via outer surface interactions, which in turn fill in the honeycomb framework structure. The amino groups at both ends of the 1,5-pentanediamine guest are situated at the entrance of the central cavity, while the alkyl chain part resides in the central cavity of the iQ[6].

Band gap and oxygen vacancy engineering of honeycomb‐like CuFe2O4 spinels toward enhanced high infrared emissivity

AbstractRecently, copper ferrites have acquired widespread attraction in high infrared radiation fields owing to their remarkable cost efficiency. However, to achieve broader applications under various operating conditions, it is essential to further improve the infrared emissivity, particularly at high temperatures. Herein, the Ni‐doped CuFe2O4 (NCFO) honeycomb‐like frameworks, which are constructed with single‐crystal nano‐subunits, are successfully fabricated via the scalable sol–gel avenue. The unique porous honeycomb framework endows NCFO with enhanced infrared absorption and relieves the stress between coatings and substrates meanwhile. With both band gap and oxygen vacancy (OV) engineering of CuFe2O4 itself via smart Ni doping, a maximum lattice strain, the richest OVs, and the narrowest band gap (∼1.63 eV) are simultaneously achieved for the CuFe2O4 with 15% Ni doping (denoted as CNFO‐15). Benefiting from the synergy of these external and intrinsic contributions, the CNFO‐15 possesses an ultrahigh infrared emissivity (∼0.975) in the wavelength range of 3–5 µm at a test temperature of 800°C. Moreover, the CNFO‐15‐based coating displays superior infrared radiation performance with outstanding high‐temperature resistance. More meaningfully, the constructive design here will provide a distinctive perspective for future large‐scale fabrication of advanced high‐infrared‐emissivity coatings.

Guest molecular guided syntheses of 2-dimensional uranyl complexes with rigid benzenedicarboxylate ligands

Two new heterometallic uranyl-organic frameworks (UOFs), [Cd(phen)2(H2O)2][(UO2)2(BDC)3]·2H2O (1) and [Ni(phen)3][(UO2)2(BDC)3]·2H2O (2), were obtained under hydrothermal conditions. Both crystal structures were characterized by single-crystal X-ray diffraction analyses and the results indicate that both complexes feature a similar 2D honeycomb framework that is connected by rigid benzenedicarboxylate (BDC) ligands and uranyl units. BDC works as a linker to bridge neighboring UO2 2+ units, where UO2 2+ is tris-chelated. Different guest molecules guided the stacking of 2D layers and lead into their 3D supramolecular crystal structures with different space groups. As a result, 1 crystallized in a polar space group Cc, whereas 2 belongs to a chiral space group P6122. Thermogravimetric measurements were performed to study their thermal stability. UV-visible diffuse reflectance spectroscopy measurements indicate an experimental optical bandgap of 3.87 eV and 3.63 eV, respectively, for 1 and 2. Luminescent studies of both samples show strong green light emissions.

Coffee grounds-based hydrogel as a high-performance and durable evaporator for solar-driven freshwater generation

Solar-driven desalination has emerged as a promising technology to mitigate the water crisis. However, challenges in developing cost-effective, eco-friendly, and durable solar evaporators from readily available materials still exist. Herein, a high-performance evaporator was developed by directly employing natural coffee grounds (CGs), a common biomass waste with huge annual discharge. The original CG particles adhere firmly to calcium alginate (CA) skeleton through a one-step freeze-drying and ionic crosslinking, thus showing outstanding mechanical properties and stability of the CG-CA composite. The formed three-dimensional honeycomb framework as well as the strong intervention of water jointly reduce the reflectance of incident photons, this enables CG-CA to display broad sunlight absorption in the wet state. As for the employed CG, no special treatment or functional processing is required. Combined with rational control of the morphology, the enlarged side surface of hydrogel acts as a cold evaporation surface to acquire energy from the surrounding, delivering an improved seawater evaporation rate of 1.59 kg m−2 h−1 with a clean water production rate of 0.62 kg m−2 h−1 under one sun illumination. The exploited solar evaporator derived from biomass waste CG suggests a practical, sustainable, and eco-friendly approach for efficient solar desalination, also for effective waste recycling.

Honeycomb Framework: Examining the Social and Personal Drivers of Fake News Sharing on Social Media Platforms

Presently, the dissemination of false news is one of the greatest problems surrounding social media platforms. Fake news is a weapon used to distort and mislead people's views, contributing to the escalation of social disputes and increase of insecurity. Honeycomb framework of social media was employed to examine various elements that impact the behavior of sharing information, including fake news. Findings show that media consumers claim to engage in fact-checking and corrective measures to prevent the propagation of misleading information. The results are inconsistent with the reality where the spread of misinformation remains a serious issue. More research is needed to further understand how the personal and sociological aspects identified by the honeycomb framework influence the spread of false news and how they relate to the worldviews of the communities in which people are embedded. It is important to comprehend fake news as a part of a wider media ecosystem.

Effect of nano precipitated calcium carbonate on the properties of hydrogels prepared with acrylamide, starch, and TEMPO-oxidized nanocellulose

A variety of water-retaining hydrogels possessing macroporous interiors resembling a honeycomb framework were developed by free radical polymerization of acrylamide (AM), starch, and TEMPO-oxidized nanofibrillated cellulose (TONFC) (Poly (AM-co-TONFC/Starch) (PATS) hydrogels). With the help of ultrasound, nano precipitated calcium carbonate (NPCC) was gelatinized in the preformed NPCC suspension in a monomer solution that forms a hydrogel. When NPCC was dispersed in water, its surface was positively charged, and NPCC could be used as a condensation center to form hydrogen bonds with AM, TONFC, and starch, shortening the distance between AM, TONFC, and starch, increasing the pore size, and thinning the pore wall. The uniform dispersion of NPCC in hydrogels could also promote a more uniform degree of cross-linking in hydrogels. When the hydrogels was extruded and deformed by external forces, the stress of hydrogels was more uniform, so that they could withstand more forces without collapsing. When 4% NPCC was added (relative to starch and TONFC), the pore size of PATS2 hydrogel was uniformly distributed in the range of 10 to 20 μm. The maximum tensile strength of PATS2 hydrogel reached 84.8 KPa, and the elongation at break was 399%. The water absorption reached 172.3, and 65% water content was maintained after 720 h.

Acetylene Separation by a Ca-MOF Containing Accessible Sites of Open Metal Centers and Organic Groups.

Efficient separation of acetylene from a ternary acetylene-containing mixture is an important and vital task in petrochemical industry, which is difficult to achieve using a single material. Herein, a new Ca2+-based metal-organic framework (MOF) [Ca(dtztp)0.5(DMA)]·2H2O (1) was constructed using the N,O-donor ligand 2,5-di(2H-tetrazol-5-yl)terephthalic acid and the less-studied alkaline earth Ca2+ ions. The MOF shows a 3D honeycomb framework based on unique metal-carboxylate-azolate rod secondary building units. Owing to the presence of high-density organic hydrogen-bonding acceptors and open metal sites (OMSs), the activated MOF shows high adsorption capacity for C2H2 and selectivity for C2H2 over CO2, C2H4, C2H6, and CH4. Dynamic breakthrough experiments indicated the actual C2H2 separation potential of the MOF from binary (C2H2-C2H4 and C2H2-CO2) and ternary (C2H2-C2H4-CO2 and C2H2-C2H4-C2H6) mixtures. Simulations revealed that the synergistic interactions between the OMSs and N atoms in MOF and C2H2 molecules play an important role in the separation of C2H2.

Crystal flex bases and the RUM spectrum

A theory of infinite spanning sets and bases is developed for the first-order flex space of an infinite bar-joint framework, together with space group symmetric versions for a crystallographic bar-joint framework ${{\mathcal {C}}}$. The existence of a crystal flex basis for ${{\mathcal {C}}}$ is shown to be closely related to the spectral analysis of the rigid unit mode (RUM) spectrum of ${{\mathcal {C}}}$ and an associated geometric flex spectrum. Additionally, infinite spanning sets and bases are computed for a range of fundamental crystallographic bar-joint frameworks, including the honeycomb (graphene) framework, the octahedron (perovskite) framework and the 2D and 3D kagome frameworks.

A new guaninate hydrate K+·C5H4N5O−·H2O: crystal structure from 100 to 300 K in a comparison with 2Na+·C5H3N5O2−·7H2O

A new guanine salt hydrate, K+·C5H4N5O−·H2O, was obtained and characterized by single-crystal X-ray diffraction in the temperature range 100 K–300 K and compared with that of the previously documented sodium salt hydrate (2Na+·C5H3N5O2−·7H2O) [Gur & Shimon (2015). Acta Cryst. E71, 281–283; Gaydamaka et al. (2019). CrystEngComm, 21, 4484–4492]. Both sodium and potassium salt hydrates have channels. However, the structure of the channels, the cation coordination, the protonation (and, respectively, the charge) of the guanine anions, as well as the role of water molecules in the crystal structure are different for the two salt hydrates. In the crystal structures of the potassium salt, the guanine anions are linked via hydrogen bonds into quartets that form open cylindrical channels in a honeycomb framework. Water molecules `line the walls' of the channels, whereas the potassium cations fill the intra-channel space. This contrasts with the structure of the sodium salt hydrate in which guanine anions form channels with water molecules filling in the channel space together with sodium cations coordinating them. The 1D anionic assembly generated through numerous hydrogen bonds and cation interactions with guanine anions and water molecules is energetically the most distinctive part of the structure of the potassium salt hydrate. In the case of the guanine sodium salt, the structure contains purely inorganic polymeric fragments – sodium cations coordinated to a water molecule forming a 1D polymeric structure and guanine anions interconnecting these polymers via hydrogen bonds with water molecules. The structural differences account for the difference in the anisotropy of strain on temperature variation for the two salt hydrates: whereas in both structures the values of the bulk thermal expansion coefficients are similar in the two structures and the major expansion is observed along the channel axes, the degree of anisotropy for the K salt is more than four times higher than that for the Na salt.

Bio-chemistry directed Li3V2(PO4)3@C cathode with honeycomb framework for long-cycle lithium ion batteries

Li3V2(PO4)3 (LVP) is a promising cathode for Li ion batteries (LIBs). But more effort need to do to improve its electronic conductivity. Honeycomb-like LVP@C materials with continuous carbon framework and hierarchical porous structure (macropores and mesopores) are successfully fabricated based on the nature lignocellulose fibers by biochemistry-directed self-assembly. The designed LVP@C has the advantage of large surface area, superior structure stability and short ion/electrons transport pathway. As the cathode for LIBs, it exhibits the initial specific capacity of 180 mAh g−1 (91% of the theoretical specific capacity) with the energy density of 666 Wh/kg, which is much better than those reported in most literatures. Moreover, it also displays outstanding long-cycle performance with almost 100% capacity retained after 500 cycles. And most importantly, the biomass material used in the fabricating process is low-cost, renewable and environmentally friendly, which can decrease the present cost of the Li ion batteries (LIBs) and reduce the environmental pollution caused by batteries. The honeycomb-like structure puts forward a new strategy to develop high-performance polyanion-based materials for low cost and high-power LIBs.

Building a Personal Brand as a CEO: A Case Study of Vivy Yusof, the Cofounder of FashionValet and the dUCk Group

Social media is a new platform for CEOs to build their image and create a strong personal brand to represent themselves and their company. This research examines an outstanding Malaysian fashion icon and social media–savvy businesswoman with over a million followers on Instagram, Vivy Yusof, the youngest Malaysian e-commerce mogul and an example of a successful CEO who has used personal branding to build an empire in the fashion industry. The objectives of this research are to identify the type of messages Vivy Yusof communicates to her audience through her personal Instagram posts and to identify the ways Vivy Yusof’s audience engages with her posts on Instagram. Her Instagram post content is classified using the Honeycomb framework that comprises seven functional building blocks, namely, presence, relationships, reputation, groups, identity, conversations, and sharing. In this study, the content of Vivy Yusof’s Instagram posts is categorized by how she focuses on the various functional building blocks in her posts and the implications these blocks have on how her audience interacts with the posts. Her social media presence confirms the importance of CEO personal branding because of her role and influence on the masses evidenced by the willingness of her followers to interact (through likes and comments) and engage with her posts on any subject matter, relating either to her business or personal life. The study contributes to a growing body of literature on personal branding strategies by shedding light on the association between content strategies and engagement with social media content.

Unfolding Utilization of Functional Blocks of Social Media in Building Brand Equity in Higher Education Institutes

The purpose of this research was to explore how HEIs are using Social Media (SM) as a marketing communication tool and to understand their branding focus through SM. It was investigated by understanding the utilization of functional blocks of SM by HEIs, which are believed to contribute towards elements of brand equity. Utilization of functional blocks of SM was studied through theoretical lens of honeycomb framework of SM. This study used qualitative methodology, based on inductive research approach. The data was collected via Netnography method, based on six months usage of SM accounts of seven selected HEIs of Pakistan, out of 225, which exhibited active SM presence. HEIs were found using nine different content types on SM. The content types that showed highest utilization of functional blocks, i.e. endorsements and promotional-messages, were amongst the least preferred content types of HEIs. However, their most preferred content types, i.e. event coverage & announcements, showed lowest engagement level, and were seen contributing towards lower stages of brand building i.e. brand image and awareness only, thus reflecting a myopic focus of HEIs in terms of their brand building through SM. Findings of this study will enable HEIs to revisit their content preference on SM based on the desired branding objectives. This research has extended theoretical knowledge regarding SM Marketing in context of HEIs. Further, it has extended comprehension of various functional blocks of SM, in organizational context, based on literature review. Keywords: Social Media Marketing, Brand Equity, Honeycomb Framework, Higher Education Institutes.

Template-Induced {Mn2}-Organic Framework with Lewis Acid-Base Canals as a Highly Efficient Heterogeneous Catalyst for Chemical Fixation of CO2 and Knoevenagel Condensation.

The target for the self-assembly of functional microporous metal-organic frameworks (MOFs) could be realized by employing ligand-directed and/or template-induced strategies, which prompted us to explore the synthetic technique of d10 secondary-building-unit-based nanoporous frameworks. Here, the exquisite combination of a paddle-wheel [Mn2(CO2)6(OH2)2] cluster and a TDP6- ligand contributes one robust honeycomb framework of {(Me2NH2)2[Mn2(TDP)(H2O)2]·3H2O·3DMF}n (NUC-31; DMF = N,N-dimethylformamide), whose activated state with the removal of associated aqueous molecules characterizes the outstanding physicochemical properties of nanochannels, penta- and tetracoordinated Mn2+ serving as highly open metal sites, rich Lewis base sites (rows of C═O groups and Npyridine atoms), and excellent thermal stability. Moreover, it is worth mentioning that Lewis acid-base sites on the inner surface of the channels in activated NUC-31 successfully form one unprecedented canal-shaped acid-base confined space with evenly distributed open metal sites of Mn2+ and Npyridine atoms as the canal bottom as well as two rows of C═O groups serving as dyke dams. Catalytic experiments displayed that activated NUC-31 could serve as an efficient heterogeneous catalyst for the chemical fixation of CO2 with epoxides into cyclic carbonates under mild conditions. Furthermore, NUC-31 could effectively catalyze the reaction Knoevenagel condensation, which should be ascribed to the synergistic polarization effect aroused from its plentiful Lewis base sites in the confined channel space. Hence, these results demonstrate that the employment of ligand-directed and template-dependent strategies could overcome the self-assembled barriers of functional microporous MOFs and achieve unexpected frameworks.