Dual Materials Research Articles

A perspective on bridging academic research and advanced testing on a path towards pilot plant implementation: A case study of integrating CO2 capture and catalytic conversion with dual function materials

As climate change intensifies, the challenges associated with CO2, including emissions mitigation, atmospheric CO2 abatement, and conversion to valuable, carbon-based products will persist for decades. There is an abundance of academic research that addresses the need for CO2 capture and conversion materials, and many of the solutions examined in the academy have shown promise under ideal conditions. The primary message of this perspective is to recognize the value of initial testing under ideal laboratory conditions while emphasizing the pressing need for further evaluations that simulate the real conditions expected in the final application. By expanding laboratory test parameters to include more realistic elements, materials can be more rigorously validated for the intended application. Success at the small-scale warrants scaled up bench and pilot plant evaluations in advance of eventual commercialization. This perspective will use dual function materials (DFMs) as a case study for discussing a scalable approach to academic research of CO2 capture and catalytic conversion. These materials combine supported adsorbents and catalysts for integrated CO2 capture from point sources and ambient air and subsequent conversion to renewable methane.

(Invited) Conducting Polymers As Dual Charge Conductors for Electrochemical Systems

Electrically conductive polymers are a class of polymers, which can conduct electricity. Conductive polymers have found niche applications such as anti-statics. The electrochemical energy storage devices, especially lithium-ion rechargeable batteries, has grown significantly in the past two decades. Recently multifunctional conductive polymers have been designed as dual ion and electron transport materials, and synthesized through a thermal process. These class of dual charge conducting polymers play a significant role as electrode binders for Silicon (Si) and Tin (Sn) alloy based anode electrode. Si is an attractive candidate for lithium-ion batteries because it delivers 10 times greater theoretical (∼4200 mAh/g) specific capacity than that of a traditional graphite anode (∼370 mAh/g). However, the widespread application of silicon materials has remained a significant challenge because of the large volume change during lithium insertion and extraction processes, disrupting both the Si electrode surface and electrode mechanical integrity. This large volume change causes electrode failure, leading to loss of the electrical contact and drastic capacity fading. Nanosizing the Si and Sn based anode materials provides better performance, but poses significant challenges to manufacturing of the electrode, including particle aggregation, and difficulties in maintaining constant electrical contacts to the nanoparticles, and excessive surface area. Conductive polymer binders can play multiple functions for Si electrode, including improved adhesion and connectivity, lithium ion compensation, better ion and electric conductivity as well as surface and interface modification. Organic and polymer chemistry has provided almost infinity possibilities to modify the polymeric binders to include the desired functionalities. This presentation will discuss the specific molecular design principles and synthetic steps to realize the structures and functionalities of the binders, how these binders interact with different alloy materials, and the electrochemical performances of the electrodes based on these binders.

Ca doping effect on the performance of La1−xCaxNiO3/CeO2-derived dual function materials for CO2 capture and hydrogenation to methane

CO2 valorization in form of synthetic natural gas is a convenient way to store large amounts of intermittent energy produced from renewable sources for long periods of time. Here reported research addresses the development of novel dual function materials (DFMs) for the utilization of CO2 from simulated post-combustion effluent by cyclic adsorption and in-situ methanation. These DFMs, obtained after the controlled reduction of 20% La1−xCaxNiO3/CeO2-type precursors (with x = 0–0.5), are widely characterized before and after catalytic tests. XRD diffractograms, H2-TPD experiments and STEM-EDS images denote that Ca-doping shows low influence on materials composition, slight detrimental effect on textural properties and no influence on Ni, La and Ce distribution. Meanwhile, the concentration of Ca-based species increases as long as La3+ substitution by Ca2+ increases, which leads to a progressively promotion of medium and, especially, strong basic sites concentration (CO2-TPD). As a result, the 20% La0.5Ca0.5NiO3/CeO2-derived DFM almost doubles (188.8 µmol g−1) the CH4 production of the 20% LaNiO3/CeO2-derived DFM (96.5 µmol g−1) at high temperatures. Indeed, this novel DFM enhances the methanation capacity of the conventional 15% Ni-15% CaO/Al2O3 DFM (143.0 µmol CH4 g−1), with higher stability during long-term experiments and adaptability under variable feed compositions, which further support the applicability of these novel DFMs. Thus, Ca doping emerges as an effective way of tailoring CO2 adsorption and in-situ hydrogenation to CH4 efficiency of 20% LaNiO3/CeO2-derived DFMs.

Construction of mechanically strong and dual network-induced elastomeric materials with self-healing functionality

Imparting contradictory features like mechanical robustness and self-healing capability in an elastomer is pretty tough. In this work, introduction of zinc dimethacrylate (ZDMA) onto macromolecular chains via ring-opening reaction and interaction between epoxy and ZDMA, a mechanically robust and dual network-induced elastomeric material with self-healing functionality was constructed in a commercially available and widely used epoxidized natural rubber (ENR). Self-adjustment of ionic moieties post deformation due to strong ionic interaction in the network along with the interdiffusion characteristics of ENR chains helps to achieve self-healing functionality. With increasing ZDMA loading, both the covalent and ionic networks increases. Surprisingly, ZDMA not only enhances self-healing ability by enhancing ionic interaction with ENR, but also enhances mechanical performance substantially by creating reinforcing effects owing to formation of ionic clusters as evident from the high-resolution transmission electron microscopy images. At 40 phr loading of ZDMA, the tensile strength and modulus at 100% elongation reached ∼14.0 and ∼3.2 MPa respectively, which were much higher than the conventional sulphur vulcanizate ENR. This work provides a facile strategy to develop a mechanically robust and self-healing elastomeric engineered materials using a widely important commercial rubber. • A new kind of mechanically strong and dual networks elastomeric materials with self-healing functionality was developed. • The developed materials showed high tensile strength (∼14.0 MPa) and 100% modulus (∼3.2 MPa). • In-situ developed ionic clusters in the rubber matrix acts as a reinforcement.

Coexistence of Strong and Weak Topological Orders in a Quasi-One-Dimensional Material.

Topological materials have broad application prospects in quantum computing and spintronic devices. Among them, dual topological materials with low dimensionality provide an excellent platform for manipulating various topological states and generating highly conductive spin currents. However, direct observation of their topological surface states still lacks. Here, we reveal the coexistence of the strong and weak topological phases in a quasi-one-dimensional material, TaNiTe_{5}, by spin- and angle- resolved photoemission spectroscopy. The surface states protected by weak topological order forms Dirac-node arcs in the vicinity of the Fermi energy, providing the opportunity to develop spintronics devices with high carrier density that is tunable by bias voltage.

Carbon doped with binary heteroatoms (N,X–C, where X = P, B, or S) derived from polypyrrole for enhanced electromagnetic wave absorption at microwave frequencies

Dual heteroatom-doped carbon materials show great promise as electromagnetic wave absorbers. However, synthesizing carbons containing multiple heteroatoms at controlled heteroatom doping levels has provided challenges to date. Herein, we report a simple method for manufacturing dual heteroatom doped carbons (N,X–C, where X = P, B, or S) by direct carbonization of polypyrrole synthesized in the presence of H3PO4, H3BO3, or H2SO4, respectively. The heteroatom content of the N,X–C products could be precisely tuned by varying amounts of acid dopant used in the polypyrrole synthesis. The N,X–C materials showed excellent electromagnetic wave absorption properties, especially N,S1–C (prepared using equimolar amounts of pyrrole and H2SO4) which offered a wide absorption bandwidth up to 6.6 GHz (11.38–18 GHz), and a RLmin of −32.3 dB (14.2 GHz) at 2.5 mm at a filler loading of 9.0 wt%. The outstanding electromagnetic wave absorption performance of N,S1–C was attributed to the presence of N dopant species, defects, C–S, and C–SOx groups, which optimized dipole polarization and conduction loss in the dielectric loss leading to excellent impedance matching.

Ultrabroad-band, white light emission from carbon dot-based materials with hybrid fluorescence/phosphorescence for single component white light-emitting diodes

Benefiting from the large Stokes shift between fluorescence and phosphorescence, fluorescence/phosphorescence dual-emitting carbon dots (CDs) have gradually entered at the stage of single-phase white light-emitting diodes (WLEDs) as ‘green material’. However, most of the developed dual-emitting CDs have weak phosphorescence, short emission wavelength and narrow emission band, resulting in relatively bluish white light emission and low color rendering index (CRI). Herein, an ultrabroad-band fluorescence/phosphorescence dual-emitting CD-based material (UB-CD@BA) is prepared by thermal treatment of boric acid (BA) and CDs with large conjugated structure. The stable covalent bonding between CDs and BA, as well as three-dimensional spatial restriction effect of self-polymerization BA molecules around CDs during long-term heating efficiently rigidified the single/triplet excited states of CDs from non-radiative deactivation, thus producing strong dual emissive materials with the high phosphorescence quantum yield of 21%. Remarkable, the prepared UB-CD@BA powders exhibit bright pure white light emission with Commission Internationale de l'Eclairage (CIE) coordinates of (0.32, 0.33) and the highest reported full width at half maximum of 250 nm. Based on the unique characteristics of UB-CD@BA, it was used as a color conversion layer to prepare a WLED with CIE coordinates of (0.35, 0.33) and the CRI value of 87.

Cage-like MnSe@PPyC/rGO as superior dual anode materials in Li/Na-ions storage

Along with high reversible capacity, superior cycling and rate performances, transition metal-based materials have been considered as promising dual anode materials for lithium/sodium ion storage. However, one of the greatest challenges during the selenization process is that the as-prepared transition metal selenides with designed morphology could retain the original morphology of transition metal oxides well. To address this key issue, in this work, a cage-like MnSe@PPyC/rGO composite is successfully developed by one-step selenization/carbonization treatment with in-situ formed polypyrrole coated MnO2 nanorods and graphene oxide as precursors, which effectively preserve the original rod-like morphology and endow a conductive network. The morphology control process, composition and microstructural change have been systematically characterized with SEM, EDS, TEM, TGA, BET, XRD, and XPS. Benefited from the above composition and structure, cage-like MnSe@PPyC/rGO exhibits good rate performance (310.3 mAh/g at 3.2 A/g) and high reversible lithium storage capacity (776.9 mAh/g at 0.1 A/g after rate testing). As anode materials for SIBs, the composite demonstrates high capacity of 546.6 mAh/g at 0.2 A/g as well as outstanding rate capability and cycle stability (294.4 mAh/g after 455 cycles at 2 A/g and 194.5 mAh/g after 2000 cycles at 10 A/g). The finding provides a new avenue for the study of transition metal/carbon composites with special morphology as dual anode materials for Li/Na-ions storage.

Variable Stiffness Conductive Composites by 4D Printing Dual Materials Alternately.

Materials that can be designed with programmable properties and which change in response to external stimuli are of great importance in numerous fields of soft actuators, involving robotics, drug delivery and aerospace applications. In order to improve the interaction of human and robots, materials with variable stiffness are introduced to develop their compliance. A variable stiffness composite has been investigated in this paper, which is composed of liquid metals (LMs) and silicone elastomers. The phase changing materials (LMs) have been encapsulated into silicone elastomer by printing the dual materials alternately with three-dimensional direct ink writing. Such composites enable the control over their own stiffness between soft and rigid states through LM effective phase transition. The tested splines demonstrated that the stiffness changes approximately exceeded 1900%, and the storage modulus is 4.75 MPa and 0.2 MPa when LM is rigid and soft, respectively. In the process of heating up, the stretching strain can be enlarged by at least three times, but the load capacity is weakened. At a high temperature, the resistance of the conductive composites changes with the deformation degree, which is expected to be applied in the field of soft sensing actuators.

Solvothermal synthesis of oxygen deficient tungsten oxide nano-particle for dual band electrochromic devices

Dual-band electrochromic smart windows can dynamically and independently control near infrared (NIR) and visible (Vis) light, and are considered a promising technology for improving building energy efficiency. However, most existing dual band electrochromic materials consist of complex nanocomposites, and it is difficult to balance the delicate composition of each constituent. Recently, to solve these problems, research has been conducted on single component dual-band electrochromic materials, in particular, oxygen deficient tungsten oxide (WO3-x) nanostructures. In this study, WO3-x nanoparticles were synthesized using a simple solvothermal method, and highly dispersible inks were formulated which could be deposited at relatively low temperature via various solution-based coating methods. Various analysis techniques including XRD, HR-TEM and in-situ spectroelectrochemical measurements revealed that the oxygen-deficient WO3-x composition remained intact up to an annealing temperature of 350 °C. Under suitable thermal treatment conditions, the resulting WO3-x films could independently and dynamically control NIR and VIS light transmittance. When a moderate voltage of −0.4 V was applied, the NIR light was mainly blocked via a capacitive charge mechanism, with optical modulations of 23.81% and 72.48% at 550 nm and 1200 nm, respectively. A further increase in applied voltage to −1.2 V led to the blocking of both VIS and NIR light through faradaic Li+ ion insertion with optical modulations of 71.13% and 84.57% at 550 nm and 1200 nm, respectively. Moreover, the optical modulations were maintained for 1000 consecutive cycles. This work demonstrates a single component dual-band electrochromic material that can be useful for various applications such as electrochromic smart windows.

Direct and continuous conversion of flue gas CO2 into green fuels using dual function materials in a circulating fluidized bed system

Carbon capture and utilization (CCU) technologies, such as CO2 methanation, generally require energy-intensive CO2 capture and separation processes prior to catalytic CO2 conversion. In contrast, integrated CO2 capture and reduction (CCR) technologies that use dual function materials (DFM) can directly convert low-concentration CO2 in flue gas or atmosphere into high-concentration CH4 or CO. In this study, we demonstrate a circulating fluidized bed (CFB) approach to enable continuous operation of CCR. In the CFB approach, the DFM (Na/Ni/Al2O3) circulates between two bubbling fluidized beds to enable steady-state cyclic operation of (1) selective capture of CO2 in flue gas/air and (2) hydrogenation of the captured CO2. We succeeded in the continuous synthesis of CH4 with high CO2 capture efficiency (>88 %) and high H2 conversion (>85 %) yielding mainly CH4 (selectivity > 99 %) as the product at high concentration (>20 % CH4) using 2 % CO2/N2 as the model flue gas.

Hydrogen sulfide gas sensing toward on-site monitoring of chilled meat spoilage based on ratio-type fluorescent probe

In this study, a fluorescence sensing platform for visual detection of hydrogen sulfide (H2S) based on ratiometric fluorescent substances was developed to real-time monitor meat spoilage. The copper nanoclusters (CuNCs) and nitrogen-doped carbon quantum dots (CNQDs) were used as dual emission fluorescence materials. The fluorescence ratio of the two wavelengths decreased in the sulphide concentration range of 0–3 μmolL(exp)−1, with a detection limit of 62.7 nmolL(exp)−1. In order to capture hydrogen sulfide gas in the air, the ratio fluorescent material is loaded on the paper base. By processing the RGB value of the photo under UV light, the detection limit of the sensor is 4.35 ppt in the range of 0 ∼ 45.2 ppt H2S gas concentration. This portable visual analysis greatly simplifies the steps of H2S gas detection while ensuring sensor stability and sensitivity. It also provides a new method for H2S detection during the meat storage process.

Sulfur tolerance and self-regeneration mechanism of Na-Ru/Al2O3 dual function material during the cyclic CO2 capture and catalytic methanation

The combined CO2 capture and methanation with Dual Function Materials (DFM) is emerging as a vibrant field of research for its potential to increase the efficiency and reduce the cost of current multistage CCU processes. In this work, we set out to investigate for the first time the impact of sulfur poisoning over a Na-Ru/Al2O3 DFM operated in a fixed bed reactor with alternate feeds under realistic conditions including the presence of SO2, H2O and O2 in the process gas stream. The results of the extensive characterization of the fresh and sulfated (reaction-aged) DFM evidenced a remarkable intrinsic tolerance of the combined CO2 capture and methanation process to high concentrations of SO2 in the feed due to a self-regeneration mechanism of the Ru catalytic sites.

A core@double‐shell structured silicon/ flower‐like manganese selenide/carbon composite as superior dual anode materials of Li/Na‐ion batteries

A core@double‐shell structured silicon/ <scp>flower‐like</scp> manganese selenide/carbon composite as superior dual anode materials of Li/Na‐ion batteries

Self-supported nickel iron selenide@nickel cobalt boride core-shell nanosheets electrode for asymmetric supercapacitors

Optimizing the electrode structure and interface is a promising approach to achieve high energy density asymmetric supercapacitors. In this study, a core–shell heterostructure based on crystalline nickel iron selenide (NiSe2-Fe3Se4) and amorphous nickel cobalt boride (NiCoB) is for the first time in-situ fabricated on carbon cloth substrate though a hydrothermal approach, a selenization process, followed by a chemical precipitation method. In this well-defined hybrid material (denoted as NiSe2-Fe3Se4@NiCoB), the close combination of NiSe2-Fe3Se4 nanosheets core and NiCoB nanosheets shell results in a large specific surface area with rich open channels, and numerous crystalline/amorphous interfaces with regulated electronic structure. Owing to its unique hierarchical pore architecture and synergistic effect of dual battery-type materials, the resultant NiSe2-Fe3Se4@NiCoB electrode displays a specific capacity of 887.0C g−1 at 1 A g−1, wonderful rate retention (71.3% at 20 A g−1), and good cycling stability (86.4% after 5000cycles). Additionally, the assembled NiSe2-Fe3Se4@NiCoB//porous carbon asymmetric supercapacitor illustrates a remarkable energy density of 72.7 Wh kg−1 at 710.7 W kg−1, and exceptional cycling life with capacity retention of 91.1% over 20,000cycles.

Multi-stimuli responsive amphiphilic diblock copolymers by a combination of ionic liquid-mediated cationic polymerization and recyclable alloy nanoparticle-mediated photoRDRP

Poly(alkyl vinyl ether)-containing multifunctional block copolymers (BCPs) are challenging to synthesize and still limited in numbers despite their possible applications in high-tech areas. This article presents the synthesis of unprecedented amphiphilic poly(2-thioethyl vinyl ether)-block-poly(poly(ethylene glycol) methacrylate) (PTEVE-b-PPEGMA) BCPs via sequential ionic liquid-mediated cationic polymerization of CEVE and recyclable alloy-mediated photoRDRP of PEGMA, followed by post-polymerization modification of the pendant -CH2CH2Cl functionality to -CH2CH2SH. Controlled nature of both the cationic polymerization and photoRDRP was demonstrated by the first-order kinetic and linear increase of molecular weight with increase of monomer conversion, keeping low dispersity values. The synthesized PTEVE-b-PPEGMA BCP exhibited a dual (redox and temperature) stimuli-response. The cloud point of PTEVE-b-PPEGMA BCP can be tuned by changing the PEGMA mol% in the BCP. Amphiphilic PTEVE-b-PPEGMA diblock copolymer undergoes self-aggregation forming spherical nano-objects. These promising PTEVE-b-PPEGMA diblock copolymers could be used for many applications, including dual stimuli-responsive materials, materials with tunable hydrophobicity, and contaminant removal.

Study of a Bimodal α–β Ti Alloy Microstructure Using Multi-Resolution Spherical Indentation Stress-Strain Protocols

Recent investigations have highlighted the multi-resolution and high throughput characteristics of the spherical indentation experimental and analysis protocols. In the present work, we further demonstrate the capabilities of these protocols for reliably extracting indentation stress-strain (ISS) responses from the microscale constituents as well as the bulk scale of dual phase materials exhibiting bimodal microstructures. Specifically, we focus on bimodal microstructures produced in an α–β Ti6242 sample. Combining the multi-resolution indentation responses with microstructural statistics gathered from the segmentation of back-scattered electron images from the scanning electron microscope allowed for a critical experimental evaluation of the commonly utilized Rule of Mixtures based composite model for the elastic stiffness and plastic yield strength of the sample. The indentation and image analyses protocols described in this paper offer novel research avenues for the systematic development and critical experimental validation of composite material models.

Emerging PEG/VO2 dual phase change materials for thermal energy storage

Emerging PEG/VO 2 dual phase change materials (PCM) with phase transition temperature gradients were prepared with polyethylene glycol (PEG) and vanadium dioxide (VO 2 ) through the vacuum impregnation method. To improve the stability, thermal conductivity, and thermal storage capacity of PEG/VO 2 , expanded graphite (EG) with different mass gradients was introduced. PEG was successfully confined as 54.48, 63.91, and 74.31 wt% in the dual composite phase change materials including 2.60, 3.28, and 3.32 wt% EG, respectively. The chemical composition and microstructure characteristics of the composite phase change material were measured by XRD, FTIR, and SEM. The thermal storage capacity of 70–113 J g −1 and phase transition temperature range of 30–70 °C for PEG/VO 2 /EG were determined by DSC. Moreover, compared with pure PEG, the thermal conductivity of PEG/VO 2 /EG 0.10 was increased by up to 93.75%, and the thermal storage capacity was increased by up to 59.35% compared with PEG/VO 2 . Compared to pure PCM, due to the improvement of thermal conductivity, the response to ambient temperature was also significantly shortened. The thermal cycling stability and thermal durability were demonstrated by the thermal cycle test and TG. Besides, PEG/VO 2 /EG 0.10 was used to simulate the thermal management of lithium-ion battery, indicating that the material had certain advantages in cooling and could improve the safety of the battery during use. PEG/VO 2 /EG 0.10 has good application potential in the field of thermal management due to the unique dual phase transition interval. • Dual phase change materials with phase change temperature gradient were successfully prepared. • The thermal conductivity of PEG/VO 2 /EG 0.10 was increased by 93.75% compared PEG and achieves a rapid heat transfer rate. • The simulated thermal management experiments of PEG/VO 2 /EG 0.10 demonstrated excellent performance.

Recent Progress in Integrated CO2 Capture and Conversion Process Using Dual Function Materials: A State-of-the-Art Review

CO2, despite its role as the primary greenhouse gas, is well-accepted as the most affordable and abundant nontoxic C1 source. Integrated CO2 capture and conversion (ICCC) is an emerging and promising process capable of reducing CO2 emissions and in-situ producing value-added products such as CH4 and syngas. This article reviews the recent research progress on the ICCC process, with an emphasis on the development of dual function materials (DFMs). The ICCC process with the combination of different CO2 catalytic conversions is first discussed from a thermodynamic point of view. The influence of operation parameters on the performance of DFMs is also summarized in detail. Then, the development of DFMs categorized by the catalytic component (i.e., Ni, Ru, etc.) is reviewed, including their performance and potential reaction mechanisms. Finally, the challenges and prospects of the ICCC process are highlighted.

Aging studies on dual function materials Ru/Ni-Na/Ca-Al2O3 for CO2 adsorption and hydrogenation to CH4

Integrated CO2 capture and utilization (ICCU) is a promising alternative to revalue CO2. In this work, the influence of the aging process on dual function materials (DFMs) Ru/Ni-Na/Ca-Al2O3, for the conversion of CO2 into CH4 is studied. DFMs are characterized by N2 adsorption-desorption, XRD, H2 chemisorption, TEM and CO2-TPD. The catalytic behavior of the prepared DFMs is analyzed in consecutive cycles of CO2 adsorption and hydrogenation to CH4. The aging process notably limits the physicochemical properties, especially the metallic dispersion. However, the CH4 production decrease is less than 25% for aged Ru-DFMs, which makes them suitable for long-term operation. The aged DFM 4Ru-8Na2CO3/8CaO-Al2O3, presents a CH4 production greater than 275 µmol g−1 with high selectivity in the range 340–400 °C. On the other hand, the aging process is more noticeable for Ni-DFMs; in fact, it limits the CH4 production to half compared to reduced Ni-DFMs.