Conversion Properties Research Articles

Ag@MXene-cellulose nanofiber composite for electromagnetic interference shielding, sensing, and actuating

With the development of flexible electronic devices, the development of flexible and multi-functional materials becomes increasingly important. In this study, we prepared Ag@MXene-cellulose nanofiber (AMC) multi-functional composites with a three-dimensional (3D) conductive network structure, which can be used for electromagnetic interference (EMI) shielding, pressure sensing, and actuating. AMC has good electrical conductivity (18.04 S cm-1) and EMI shielding effectiveness (37.7dB). The microstructure of the AMC surface gives it the potential to be applied in the pressure sensor. AMC is humidity-sensitive and has excellent electrical/photo-thermal conversion properties. Thus, AMC can be used to fabricate humidity-driven actuators and electrical/light-driven actuators. Finally, three multi-functional devices/systems have been carefully designed to achieve the fabrication of multi-functional devices/systems that rely on only one raw material, which significantly simplifies the preparation of multi-functional devices. We hope this research will open up new ways for artificial muscles, soft robots, and EMI shielding devices.

Preparation of “dry water”-type liquid marbles with enhanced mechanical stability and CO2 capture performance

Liquid marbles(LMs) are formed by encapsulating liquid with hydrophobic particles showed potential application in capturing CO2. However, conventional LMs are mostly millimeter scale and easily deformed by extrusion. This study aimed to enhance the mechanical stability by controlling the particle size to prepare “dry water” type LMs (DWLMs). The N-methyldiethanolamine (MDEA) solution was used as the core in constructing DWLMs, and SiO2/graphene(GPE) was used as the shell material. The incorporation of GPE can endow DWLMs with photothermal conversion properties, with a particle size distribution around 100 ∼ 250 μm occupying the largest volume fraction. These DWLMs exhibited good flow ability and mechanical stability. Moreover, the effects of MDEA concentration, and content of SiO2/ GPE on the preparation of DWLMs were investigated. Under an illumination intensity of 1 × 106 Lux, the temperature of DWLMs reached above 95 °C. Subsequently, the absorption performance was examined by a fixed-bed absorption tower, and it was found that decreasing the droplet size can increase the gas–liquid mass transfer area to reduce the mass transfer resistance. The height of the fixed bed constructed by DWLMs was higher than 7 cm, and the bottom particles can still maintain stability without agglomeration and blocking the supporting mesh. The breakthrough point (t0.5 and t0.95) of large-DWLMs (L-DWLMs) were greater than that of tiny-DWLMs (T-DWLMs). The absorption kinetics have validated that chemisorption is the primary mode of CO2 absorption. In desorption process, the results showed that the desorption of CO2 was realized by photothermic desorption, and the desorbed DWLMs were regenerated and recycled, which could prevent the corrosion of the device as well as utilize the energy provided by the sunlight.

Black phosphorus-loaded anisotropic nanofiber sponges for random skin flaps regeneration

Electrospun nanofibers have been showing their estimable values as tissue engineering scaffolds. Notably, the oriented structure and intelligent responsiveness are significant directions to enhance the application value of the nanofibrous scaffolds. Here, we present a novel 3D anisotropic and responsive nanofiber sponge scaffolds (ARNFSs) loaded with black phosphorus (BP) and vascular endothelial growth factors (VEGF) for random skin flaps regeneration. Aligned polycaprolactone (PCL) nanofibrous mat prepared by electrospinning technology acted as host materials of sponge scaffolds, which were foamed by soaking in sodium borohydride (NaBH4) solution and filled with poly(N-isopropylacrylamide) (pNIPAM) hydrogel. The highly oriented 3D nanofiber sponge scaffolds can guide the growth of cells along the fibers. Utilizing the superior photothermal conversion properties of BP and thermal responsive ability of pNIPAM, VEGF could be controllably released with the irradiation of near-infrared (NIR) light, thus promoting the angiogenesis of random skin flaps. Notably, in vivo experiments have further proved that our 3D ARNFSs have remarkable performance in enhancing the survival of random skin flaps, indicating their significant value in clinical tissue regeneration and other correlative biomedical fields.

Polymerization of acrylonitrile in dimethyl carbonate: A kinetic and mechanistic study

For the first time, a new polymerization medium, dimethyl carbonate (DMC), was used for the polymerization of acrylonitrile (AN), and polyacrylonitrile (PAN) powder was obtained successfully. The effects of polymerization factors, including monomer concentrations, temperature and initiator concentrations on the structures and properties of PAN powders were investigated by nuclear magnetic resonance spectroscopy (NMR), total internal reflectance Fourier transform infrared spectrometer (FTIR), wide-angle X-ray diffractometer (WXRD) and thermal gravimetric analyzer (TGA). The polymerization kinetic and mechanistic study of PAN with DMC as the polymerization medium were discussed in details. There are three key achievements in this paper. First, the kinetic equation of PAN polymerization with DMC as a medium was established: Rp = K[ABVN]0.92[AN]6.78. This result shows that the Rp is highly dependent on the AN concentrations. Second, the chain transfer constant of DMC was measured to be 4.57 × 10−4 at 60 °C, and the chain transfer constant increases with polymerization temperature. Lastly, the structures and properties of PAN powders prepared with H2O, tetrahydrofuran (THF) and DMC as media were compared. The results showed that the PAN prepared with DMC as a medium by free radical polymerization had a higher conversion, molecular weight and better crystalline property compared to THF. These findings indicate that DMC is a promising medium for manufacturing high quality PAN powder by free radical polymerization.

Schottky Interface Engineering in Ti3C2Tx/ZnS Organic Hydrogels for High‐Performance Multifunctional Flexible Absorbers

AbstractWith the rapid advancement of wearable electronics, soft robotics, and camouflage technologies, there is an urgent demand for flexible, multifunctional electromagnetic wave absorbing materials. Traditional absorbers, including metal‐ and carbon‐based materials, often lack the flexibility required for such applications. In this work, a novel strategy is proposed for developing a flexible absorber by combining a conductive filler with a Schottky heterogeneous interface and a polymer network framework. Ti3C2Tx MXene is modified with ZnS via a low‐temperature hydrothermal method, forming a Ti3C2Tx/ZnS composite. This composite is subsequently embedded in a copolymer matrix of polyvinyl alcohol (PVA) and acrylamide (AAm), dispersed in a binary water‐glycerol solution. The Schottky interface between Ti3C2Tx and ZnS enhances electron transfer at the heterophase boundary, significantly improving interface polarisation. Simultaneously, interactions between water and glycerol restrict the rotation of polar molecules under external electromagnetic fields, optimising polarisation loss within the gel. Experimental results demonstrate that the Ti3C2Tx/ZnS gel achieves a minimum reflection loss (RLmin) of −43.76 dB at 8.79 GHz, with an effective absorption bandwidth (EAB) covering the entire X‐band. Additionally, the gel exhibit exceptional stretchability, frost resistance, shape adaptability, and photothermal conversion properties.

Alternating Donor-Acceptor Ladder-Type Heteroarene for Efficient Photothermal Conversion via Boosting Non-Radiative Decay.

The development of novel ladder-type conjugated molecules is crucial for advancing supramolecular chemistry and material science. In this study, we report a straightforward synthesis of new alternating donor-acceptor (D-A) ladder-type heteroarene, FCDTDPP, and demonstrate its application as photothermal agent for imaging and cancer therapy. FCDTDPP is constructed by vinylene bridge between cyclopentadithiophene (D) and diketopyrrolopyrrole (A) through intramolecular Friedel-Crafts type reaction. FCDTDPP exhibits unique combination of good molecular planarity, efficient intra/inter-molecular mixed D-A interactions, and local aromaticity. These features collectively contribute to its broad and intense absorptions with narrow bandgap in red band of the spectra, coupled with multiple vibrational absorption feature, thereby enhancing non-radiative decay process and resulting in efficient photothermal conversion property. FCDTDPP and its nanoparticles (NPs) exhibit superior photothermal conversion performance and stability under 660 nm laser irradiation. Moreover, in vitro studies reveal that FCDTDPP NPs possess excellent biocompatibility, low cytotoxicity, and robust photothermal therapeutic efficacy, a finding further corroborated by preliminary in vivo experiments in tumor-bearing mice. This work charts a novel course for the molecular engineering of organic photothermal conversion systems, propelling relevant research forward.

Alternating Donor‐Acceptor Ladder‐Type Heteroarene for Efficient Photothermal Conversion via Boosting Non‐Radiative Decay

The development of novel ladder‐type conjugated molecules is crucial for advancing supramolecular chemistry and material science. In this study, we report a straightforward synthesis of new alternating donor‐acceptor (D‐A) ladder‐type heteroarene, FCDTDPP, and demonstrate its application as photothermal agent for imaging and cancer therapy. FCDTDPP is constructed by vinylene bridge between cyclopentadithiophene (D) and diketopyrrolopyrrole (A) through intramolecular Friedel‐Crafts type reaction. FCDTDPP exhibits unique combination of good molecular planarity, efficient intra/inter‐molecular mixed D‐A interactions, and local aromaticity. These features collectively contribute to its broad and intense absorptions with narrow bandgap in red band of the spectra, coupled with multiple vibrational absorption feature, thereby enhancing non‐radiative decay process and resulting in efficient photothermal conversion property. FCDTDPP and its nanoparticles (NPs) exhibit superior photothermal conversion performance and stability under 660 nm laser irradiation. Moreover, in vitro studies reveal that FCDTDPP NPs possess excellent biocompatibility, low cytotoxicity, and robust photothermal therapeutic efficacy, a finding further corroborated by preliminary in vivo experiments in tumor‐bearing mice. This work charts a novel course for the molecular engineering of organic photothermal conversion systems, propelling relevant research forward.

Shape memory, reprocessable and photothermal networks of polyurethane with silyl ether bonds and croconaine segments

Organic dyes were integrated into networks of polyurethane (PU) in the form of croconaine segments, in order to bestow photothermal properties on the materials. In addition, the PU networks were crosslinked with polysilsesquioxane (PSSQ) so that the materials can be reprocessed (or self-healing) via the metathesis of silyl ether bonds under catalysis. Toward this end, we synthesized a novel diol bearing croconaine moiety, which was used as one of chain extenders and a series of linear PU telechelics with dihydroxyl termini were synthesized. The α,ω-dihydroxyl PU telechelics were then allowed to react with 3-isocyanatopropyltriethoxysilane to gain α,ω-ditriethoxysilane PU telechelics. Through sol-gel process, α,ω-ditriethoxysilane PU telechelics readily underwent crosslinking with PSSQ as the crosslinkages. The crosslinking of PU was in marked contrast to traditional crosslinking of PU with multifunctional ols (or amines) as the crosslinkers. Owing to the crosslinking, shape memory properties were bestowed on the organic-inorganic PU networks. Thanks to the metathesis of silyl ether bonds under catalysis, the organic-inorganic PU networks were reprocessable (or recyclable). Benefiting from the built-in of dye segments, the PU networks significantly displayed excellent photothermal conversion properties. By leveraging the photothermal properties, the shape shifting of the PU networks can be triggered via the irradiation under infrared laser and in a non-contact fashion. In addition, the PU networks were capable of displaying the light-triggered self-healing properties. Thanks to these excellent properties, we demonstrated a successful application of the PU networks a soft robot.

Plasmonic Nanocomposite for Visible Light‐Modulated Bimorph‐Actuator

AbstractSoft actuators have great potential applications in sophisticated movement and sensitive devices due to their flexible nature, good interaction, and precise control. However, existing carbon‐based optical actuators are limited in their response under visible light irradiation. The limited visible light absorbance of the carbon nanostructure brought the metallic nanoparticle into the soft actuators that can absorb visible light. This study introduces a new type of plasmonic photothermal‐bimorph actuator, using graphene oxide (GO), reduced graphene oxide (rGO), and silver nanorods (Ag NRs) to overcome the limitations of traditional optical actuators. The bimorph film is actuated by visible and near‐infrared light stimuli with various power densities showing reversible deformation behavior. The actuator shows significant bending associated with a ≈50° change in bending angle under visible light irradiation with a response time of ≈5 ± 1 sec. Furthermore, a smart photo‐controlled non‐contact switch is fabricated based on photo‐thermal conversion properties, demonstrating perfect integration of plasmonic bimorph actuators. The density functional theory based molecular dynamics calculations provide an additional understanding of the bending of actuators under external stimulus. Using illustrative demonstrations of actuators, these results hint at a method for generating multipurpose visible light‐based soft robots, supporting a new approach to developing an optical locking system.

Enhancement in Photodetector Sensitivity Using All‐Inorganic Perovskite Absorber RbGeI3 and Copper Bismuth Thiocyanate for Superior Charge Transport

This study investigates a photodetector design using the nontoxic, all‐inorganic perovskite material RbGeI3, which is distinguished by its efficient light absorption and excellent photoelectric conversion properties. Incorporating copper bismuth thiocyanate (CBTS) and indium gallium zinc oxide layers, this design enhances charge transport, leading to a photodetector that exhibits exceptional sensitivity across the visible spectrum, along with a peak responsivity of 0.63 A W−1 and a detectivity of 1.37 × 1013 Jones in the near‐infrared (NIR) at 900 nm. The proposed photodetector exhibits wide‐spectrum detection, encompassing both the visible range and the NIR region. These results position RbGeI3 and CBTS as compelling alternatives to traditional photodetector materials such as Si‐Ge, InGaAs, ZnO, and GaN. Validation is achieved through simulations using the SCAPS‐1D simulator, underscoring the potential of perovskite materials for advanced photodetector applications.

Highly efficient solar steam evaporation via elastic polymer covalent organic frameworks monolith

Three-dimensional solar steam evaporators with efficient water purification performance have received increasing attention recently. Herein, elastic polymer covalent organic frameworks (PP-PEG) containing PEG chains with intriguing adaptability to guests are prepared by forming porphyrin rings. PP-PEG foams demonstrate full spectrum absorbance and excellent photothermal conversion properties. Through well-designed thermal management and optimization of the hydrophilicity and PEG chain length, we obtain a highly efficient solar evaporator with an evaporation rate of 4.89 kg m−2 h−1 under 1 sun in self-contained mode. The optimized solar evaporation rate is increased to 18.88 kg m−2 h−1 under 1 sun with a facile truncated cone reflector, exceeding all known solar steam evaporators. This innovative design holds immense promise for desalination and water purification owing to its simple preparation, high efficiency and durability.

Novel rod-like bifunctional nanocomposites: Enhanced NIR-IIb luminescence and microwave heat conversion property by local surface plasmon resonance effect and space-dielectric confinement effect

A novel halloysite nanotubes(HNT)@WO3-x@GdF3:Yb3+,Er3+ rod-like bi-functional nanocomposites with strong NIR-IIb (near-infrared second window 1500–1700 nm) luminescent and microwave heat conversion property was obtained by introducing the local surface plasmon resonance effects (LSPR) and the space-dielectric confinement effect. The novel nanocomposites were characterized in terms of the structure, morphology and property. The result of XRD, SEM and TEM analysis showed that WO3-x and GdF3:Yb3+,Er3+ nanocrystals were successfully deposited on the surface of HNT. In comparison to GdF3:Yb3+,Er3+, the NIR-IIb emission intensity of HNT@WO3-x@GdF3:Yb3+,Er3+ rod-like nanocomposites is significantly enhanced (8.4 times) and improved fluorescence lifetime (0.1591us to 0.1725 us) at 808 nm excitation. This results suggested that LSPR of WO3-x can regulate the NIR-IIb luminescent properties of HNT@WO3-x@GdF3:Yb3+,Er3+ nanocomposites. And HNT@WO3-x@GdF3:Yb3+,Er3+ rod-like nanocomposites had stronger microwave thermal conversion property based on space confinement effect and dielectric confinement effect. The HNT@WO3-x@GdF3:Yb3+,Er3+ rod-like nanocomposites successfully combined NIR-IIb luminescent and microwave heat conversion property to one, in addition, halloysite nanotubes be endowed to NIR-IIb luminescent properties and microwave heat conversion property. This study provides a new idea and method for the preparation of new bi-functional nanocomposites.

Structure and properties of aluminum alloy composite conversion coating

The intrinsic corrosion resistance of aluminum alloy is relatively poor and needs to be enhanced through anodic oxidation treatment. Traditional anodic oxide films predominantly consist of aluminum oxide and are characterized by low toughness and poor impact resistance, making them unsuitable for environments with high temperatures, large temperature variations, and stringent corrosion resistance requirements. This study employs oxalic acid and trace amounts of ammonium fluoride as the electrolyte for anodic oxidation treatment of 6061 aluminum alloy. Through electrochemical oxidation and chemical co-deposition, a composite oxide film is prepared. The composition of the oxide film includes Al2C6O12, AlF3, AlOOH, and amorphous Al2O3, exhibiting a micro-porous structure with an average pore diameter of 10–20 nm. The surface of the micropores is covered by a relatively dense chemical conversion film, which seals the micropores and enhances the corrosion resistance of the oxide film. When the concentration of oxalic acid is 10 g/L and the concentration of ammonium fluoride is 0.5 g/L, the composite oxide film does not crack when bent at 90° at room temperature. Furthermore, no cracks are observed after heating to 100°C and holding for 30 min or even after maintaining at 300°C for 6 h. The electrochemical impedance reaches 5.891 × 106 Ω cm2, while the sulfuric acid anodic oxide film develops cracks when bent at 30° at room temperature or heated to 58°C, with a low-frequency impedance value of 3.649 × 105 Ω cm2.

Rearrangement of cellulose molecular chains in situ for stabilizing two-dimensional nanochannels

Two-dimensional (2D) nanochannels originating from ordered stacking of nanosheets exhibit great potential in osmotic energy harvest, which provides a promising way to address the increasing energy crisis. Although polymer nanorods have unique advantages in constructing and adjusting 2D nanochannels, the stability of these nanochannels still faces great challenges. Herein, cellulose nanocrystal (CNC) nanorods are intercalated between graphene oxide (GO) nanosheets to construct 2D sub-nanochannels. Ordered sub-nanochannel structures are first formed through a vacuum assisted self-assembly of CNC and GO. A facile strategy involving the rearrangement of cellulose molecular chains in situ is subsequently employed to stabilize the dimensions and arrangement of the sub-nanochannels. After the rearrangement, the mechanical properties and water stability of the sample are greatly enhanced due to the increased dynamic hydrogen bond network, and tensile strength and strain at break are increased by 88.7% and 472.2%, respectively. Additionally, the prepared membrane exhibits a power density of 0.49 W m-2 under a 50-fold salinity gradient with a long-term stability and could be further improved to 0.75 W m-2 by reducing the ion transport distance. The photo-thermal conversion property of the membrane could also benefit the osmotic power generation. Our work opens new insights into stabilizing the dimensions and arrangement of 2D nanochannels constructed by nanorods and nanosheets for commercial osmotic power generation.

An effective and specific cancer theranostic nanoplatform with NIR-II fluorescence imaging-guided photothermal/chemodynamic therapy

Nanomaterial-based second near-infrared region (NIR-II) fluorescent probes have deep tissue penetration. However, it is limited by low catalytic efficiency and specific recognition in the tumor microenvironment (TME). Herein, Ag2S-Cu(II)-Cu2-xSe diagnostic nanoparticles have been established by Cu2-xSe and Ag2S QDs, which can serve as diagnostic agents. They can improve the precise diagnosis of cancer via a NIR-II imaging-guided multimodal photothermal/chemodynamic therapy strategy under near-infrared (808 nm) light irradiation. Under neutral conditions, the fluorescence of Ag2S-Cu(II)-Cu2-xSe nanoplatforms is in the “off” mode, which is selectively turned on only in the tumor microenvironment. Ag2S-Cu(II)-Cu2-xSe NPs not only emit fluorescence specifically in the TME but also have efficient photothermal conversion properties. Significantly, Ag2S-Cu(II)-Cu2-xSe has experimentally demonstrated a strong combined therapeutic effect and can consume excess intracellular glutathione (GSH) through redox reactions. This work presents an effective strategy for achieving precise and safe multifunctional nanodiagnostic platforms.

Boosting Electrocatalytic Performance of Sulfide Oxidation on Polyoxomolybdates with Synergistic Effects of CNT‐Doped Aerogel Foams

AbstractThe meticulous design of highly efficient indirect electrocatalysts with value‐added conversion properties remains a substantial challenge within the realm of organic catalysis. While polyoxometalates (POMs) serve as crucial active centers in catalytic modeling systems for chemical materials, their exploration in electrocatalytic organic molecular transformations is hindered by kinetic barriers. Therefore, an efficient protocol is established for the synthesis of electrocatalysts utilizing polyoxomolybdates (CuMo6) immobilized on aerogel foams (CMC). The electrical conductivity and electrocatalytic activities of the electrocatalyst (CuMo6/CNT@CMC) can be readily enhanced by adjusting the microenvironment between the CuMo6 and CMC using carbon nanotubes (CNT). Controlled experiments demonstrate that the CuMo6/CNT@CMC electrocatalyst for the oxidation of sulfide achieves an impressive Faradaic Efficiency (FE) exceeding 95% under ambient conditions, while the working potential is markedly lower than that of reported heterogeneous electrocatalysts. Combined experimental and theoretical analyses suggest that the modulated electronic synergistic interaction between the Cu‐assisted Mo sites and CNT within foam favors the appropriate binding of PhCH3S+• intermediates, thereby promoting the selective oxidation of sulfides. This study paves the way for the utilization of polyoxometalate‐based materials with simple synthesis methods for various electrocatalytic applications.

The effect of ultrasonic waves on the structure, morphology, and thermal conductivity of graphene oxide as nanofluids for direct absorption solar collector application

This research aims to explore how ultrasonic waves affect the structure and morphology of graphene oxide (GO) as a nanofluid, influencing its thermal conductivity (TC), stability, and photo-thermal conversion properties. GO was rapidly synthesized under ultrasonic bath irradiation using modified and improved Hummers' methods. Ultrasonic irradiation creates different structural and morphological defects in the GO that depend on the sonication time. The relationship between the exposure time to ultrasound and the creation of structural and morphological defects in graphene oxide nanosheets was investigated using UV–Vis, FTIR, Raman spectroscopies, AFM, and TEM analysis. The study examined how the structure and morphology of graphene oxide nanosheets affect the thermophysical and photo-thermal conversion properties of nanofluids by comparing heat transfer and stability. The simultaneous characterizing of the structure and morphology indicates that TC and stability are related to the sonication time. Indirect sonication with low intensity can carefully control the oxidation reaction of GO. Sonication for 30 min creates GO nanosheets that yield stable nanofluids with a 32.31 % enhancement in TC, with no extra treatment needed. This particular nanofluid has excellent photo-thermal conversion properties thanks to its high optical absorption, good stability, and thermal conductivity. This can increase the solar-thermal conversion efficiency (η) up to 72.5 %, making it a promising candidate for use as the working fluid in direct absorption solar collectors (DASCs)

Honeycomb shaped carbon dopped 1T-2H-MoS2 heterojunction counter electrode with high short current for dye sensitized solar cells

Recent years have witnessed energy crises in various regions and the utilization of new energy is crucial. Dye-sensitized solar cells (DSSCs) are the third generation of photovoltaic cells that are expected to be more cost-effective than other types of solar cells. In this work, we report the synthesis of 1T-2H-MoS2/honeycomb shaped carbon (HSC) heterojunction composite counter electrodes for DSSCs via adding porous carbon in the facile hydrothermal method. The effects of HSC on the morphology, structure, electrochemical and photoelectric conversion properties of the 1T-2H-MoS2/HSC composites were investigated systematically. Both the results of electrochemical and photoelectric measurement suggest the excellent performance of the reduction of I3- and the regeneration of dye. The whole cell assembled with the MoS2/HSC-5.0 counter electrode achieved a short current density 22.24 mA∙cm−2 and a power conversion efficiency (PCE) of 8.42 %, which is significantly higher than that of the pure MoS2 electrode (5.89 %) and Platinum electrode (6.76 %), implying the MoS2/HSC-5.0 composite is a promising candidate for counter electrodes catalyst of DSSCs.

Graphene Microflower by Photothermal Marangoni-Induced Fluid Instability for Omnidirectional Broadband Photothermal Conversion.

2-D carbon-based materials are well-known for their broadband absorption properties for efficient solar energy conversion. However, their high reflectivity poses a challenge for achieving efficient omnidirectional light absorption. Inspired by the multilevel structures of the flower, a Graphene Microflower (GM) material with gradient refractive index surface was fabricated on polymer substrates using the UV-intense laser-induced phase explosion technique under the synergistic design of the photothermal Marangoni effect and the fluid instability principle. The refractive index gradient reduces light reflection and absorbs at least 96% of light at incident angles of 0-60° across the entire solar wavelength range (200-2500 nm). Over 90% absorption even at 75° angle of incidence. The light absorption is enhanced by the multiple interferometric phase cancelation and localized surface plasmon resonance, resulting in a steady-state temperature 60 °C higher than ambient conditions under one solar irradiation. The max rate of temperature rise can reach up to 62 °C s-1. The device is then integrated at the hot end of the temperature difference generator at high altitude to ensure continuous and efficient power generation, producing a steady-state power of 196 mW.

2D-3D electron transfer functions and stability of sustainable graphitic biocarbon for bipolar plate application

Biocarbon being a highly demanding renewable source of carbon is important for many applications such as soil enrichment, electronic applications, etc. In this research, sustainable waste biomass-to-energy materials conversion, kinetic, thermodynamic and electronic properties of carbonized forest biomaterials were investigated to evaluate their high-potential in bipolar plate for fuel cell application. In thermogravimetric analysis, the lignin biocarbon showed the least activation energy of 95 KJ/mol compared to 127 and 145 KJ/mol for hardwood and softwood biocarbons respectively. The crystallographic nature of carbonized ligneous and cellulosic biomaterials was also investigated, showing its intrinsic properties and exotic functionality through semi-metallic properties determined from density function theory, transmission electron microscopy and UV–Vis absorption. Finally, the electrochemical properties of bio-carbon composites were examined to prove stability and corrosion resistance comparable to metallic plates. Biocarbon composites showed high polarization resistance up to 5.96 kΩ-cm2 with non-reactive properties, favorable to use in bipolar plates as an alternative to metallic plate which is expensive and prone to corrosion. Overall, sustainable biocarbon shows its ability as a high-performance functional material alternative to expensive nanofillers as well as to enhance the attributes of the bipolar plate composite by increasing connectivity between primary filler and insulating resin.