Biomorphic Materials Research Articles

Low-temperature and high-response NO2 sensor based on oxygen vacancy-enriched ZnO tubes inherited from waste chestnut mesocarps

Herein, we reported a low-cost ZnO biomorphic material used for low-temperature and high sensing detection of trace NO2. It was simply prepared by calcining Zn(NO3)2 solution soaked waste chestnut mesocarp biotemplate at 600 °C in air for the first time. The morphology of ZnO-6 material displays one-dimensional (1D) tubular structure assembled from uniform nanoparticles, and it has small mesopore distribution, relatively large specific surface area and abundant oxygen vacancy defects. The synergy of above advantageous factors provides a convenient channel for gas diffusion, and increases the surface active sites for adsorption and chemical reactions, which in turn efficiently enhances sensing performance of ZnO material towards NO2. At 92 °C, ZnO-6 sensor achieves a high response of 365 towards 10 ppm NO2, which is 30.4 times than that (S = 12) of template-free ZnO-0 sample. Also, it is larger than most reported 1D ZnO-based NO2 sensors. This sensor still possesses fast recovery characteristic, low detection limit, and good moisture tolerance. Moreover, the improved NO2 gas-sensing mechanism is discussed in more detail.

Additively manufactured biomorphic cellular structures inspired by wood microstructure

Biological cellular materials are an important area of research in Additive manufacturing due to their intricate lightweight designs and forms with high energy absorption characteristics under compressive loading. In this study, we utilize the capability of Additive Manufacturing (AM) technology, experimental testing, and Finite Element Analysis (FEA) to design and investigate the mechanical behavior and energy absorption capabilities of novel Biomorphic Cellular Structures (BCS) inspired by the microstructure of cedar, oak, and palm wood. A comparative study of the elastic properties of the biomorphic cellular structures is carried out. The deformation and failure modes of the different cells were studied, and their performance was also discussed. Nonlinear finite element numerical simulation conducted has shown high accuracy in the prediction of deformation of the samples manufactured using additive manufacturing. The results show that cedar-bcs provides the best mechanical performance compared to the other two biomorphic cellular structures which could be as a result of its more vertical cell wall orientation, nevertheless, the palm-bcs showed a step-wise deformation and improved collapse stress. The obtained results suggest that the unique opportunities offered by the proposed experimental method, in combination with computational models, could serve to provide novel important information for the rational design of additively manufactured porous biomorphic materials.

Synthesis of carbon nanotubes on silicalite-1-coated biomorphic materials

Synthesis of carbon nanotubes on silicalite-1-coated biomorphic materials

Biomorphic Ceramics: Synthesis and Characterization of Preceramic Polymer-Modified Melanin.

Recent efforts have demonstrated that the morphology of ceramics can be manipulated to control both their deformation mechanism and mechanical performance. However, precise control of the ceramic nanostructure is still difficult to achieve. Biotemplating, leading to biomorphic materials, provides a facile route to manipulate the nanostructure of the resulting materials, and the use of melanin as a coating provides a new route to biotemplated materials. Melanin is underutilized for structural materials partly due to the cost of procuring it from natural sources and the inability to control the shape and sizes of melanin particles. Taking a combined synthetic biology and chemical synthesis approach, we report the melanization of Escherichia coli and its subsequent silanization and functionalization with preceramic polymers to make novel biomorphic silicon-based ceramic materials. Graft-to and graft-from reactions were used to append preceramic polymers to the melanin, followed by pyrolysis under argon. Samples were analyzed by FTIR, XRD, XPS, and TEM and found to retain the shape and size of the original cells with high fidelity. The homogeneity of coverage and yield of the resulting ceramic materials depended on the type of grafting reaction. This work provides a promising proof-of-concept that bacterial-templated ceramics can be readily made and opens a host of possibilities for further studies and applications.

Study of biomorphic calcium deficient hydroxyapatite fibres derived from a natural Harakeke (Phormium tenax) leaf fibre template

The complex structure of natural bio-organic matter has inspired scientists to utilise these as templates to design ‘biomorphic materials’, which retain the intricate architecture of the materials while acting as a useful bioactive material. Biomorphic hydroxyapatite-based fibres were synthesised using Harakeke leaf fibre as a template, which constitutes a powerful method for manufacturing bioactive ceramic fibres. Furthermore, in creating the hydroxyapatite-based fibres, a natural source of calcium and phosphate ions (from bovine bone) was utilised to create the digest solution in which the leaf fibres were immersed prior to their calcination to form the inorganic fibres. Chemical, thermogravimetric and microscopic characterisation confirmed that the final product was able to successfully replicate the shape of the fibres and furthermore be transformed into calcium deficient, bone-like hydroxyapatite.

A sustainable multi-function biomorphic material for pollution remediation or UV absorption: Aerosol assisted preparation of highly porous ZnO-based materials from cork templates

For the first time, highly porous ZnO-based biomorphic materials were synthesised using cork as a natural sustainable template. In the first step, waste cork powder was pyrolysed and converted into inorganic carbon. This template was then infiltrated using a novel approach employing an aerosol of zinc-containing solutions. The infiltrated powders were calcined to convert the precursors into zinc oxide. Depending on temperature, these could form either a ZnO-graphite composite material, or pure ZnO. Their morphology, porosity, microstructure and composition were characterised; their optical band gap energies, ability to adsorb and photodegrade organic pollutants and UV absorption were also assessed. When heated to 350 °C they maintained the 3D porous cork structure, producing a graphite-containing composite material, with both physical adsorption and photocatalytic activity (Eg = 3.19 eV), suitable for environmental remediation. When heated to 700 °C, the powders were pure ZnO (no graphite), and they absorbed in the UV region, hence suitable for use as sunscreen. Doped ZnO ecoceramics were also produced, using silver and aluminium. An addition of 1 mol% Ag improved photocatalysis under solar light. Conversely, adding 2 mol% Al and calcining at 700 °C deactivated photocatalysis, but maintained strong UV absorption, producing a safer sunscreen material (no generation of free radicals). This is the first time that photocatalytic or UV absorption properties of any wood-derived biomorphic material or ecoceramic have been reported.

Biomorphic CoNC/CoOx Composite Derived from Natural Chloroplasts as Efficient Electrocatalyst for Oxygen Reduction Reaction.

Natural chloroplasts containing big amounts of chlorophylls (magnesium porphyrin, Mg-Chl) are employed both as template and porphyrin source to synthesize biomorphic CoNC/CoOx composite as electrocatalyst for the oxygen reduction reaction (ORR). Cobalt-substituted chlorophyll derivative (Co-Chl) in chloroplasts is first obtained by successively rinsing in hydrochloric acid and cobalt acetate solutions. After calcining in nitrogen to 800 °C, Co-Chl is transferred to CoNC; while other parts of chloroplasts adsorbed with Co ions are transferred to CoOx retaining the microarchitecture of chloroplasts. The abundant active CoNC sites are protected by circumjacent biocarbon and CoOx to avoid leakage and agglomeration, and at the same time can overcome the poor conductivity weakness of CoOx by directly transporting electrons to the carbonaceous skeleton. This unique synergistic effect, together with efficient bioarchitecture, leads to good electrocatalytical performance for the ORR. The onset and half-wave potentials are 0.89 and 0.82 V versus reversible hydrogen electrode, respectively, with better durability and methanol tolerance than that of commercial Pt/C. Different from the traditional concept of biomorphic materials which simply utilize bioarchitectures, this work provides a new example of coupling bioderivative components with bioarchitectures into one integrated system to achieve good comprehensive performance for electrocatalysts.

Biomorphic composites composed of octahedral Co3O4 nanocrystals and mesoporous carbon microtubes templated from cotton for excellent supercapacitor electrodes

Biomorphic Co3O4 nanocrystal/mesoporous carbon microtube composites have been hydrothermally prepared and subsequent calcinated using cotton as biotemplate and precursor. The as-prepared composites are fabricated by octahedral Co3O4 nanocrystals with high exposed {1 1 1} facets supported on the porous carbon microtubes and exhibit a unique tubular morphology and porous features. The specific capacitance of the present biomorphic materials is 284.2F⋅g−1 at 1 A⋅g−1, which is 4.8-fold larger than that of pristine Co3O4 prepared without cotton template. The excellent pseudocapacitive performance is attributed to the introduction of porous carbon, the high exposed active facets, the high specific surface area and the optimized hierarchical microstructure inherited from the biotemplate.

Route to design highly efficient thermal rectifiers from microstructured cellular biomorphic materials

The application of electronic diodes has greatly motivated the development of industrial engineering, while predictably, thermal rectifiers, as thermal manipulation devices, might have broad applications in the renewable energy engineering. Here, we report a significant thermal rectification phenomenon observed by using a thermal rectifier solid-state device comprising microstructured cellular biomorphic materials and by measuring the thermal conductivities in the forward and reverse directions over a wide temperature range. Our theoretical studies, based on analytical method and simulation of finite element method, attributed the asymmetry of thermal transition in opposite directions to the microstructured cellular size-gradient geometry. We further demonstrated that the thermal rectification phenomenon was only observed when the thermal conductivity of the filled materials showed monotonic temperature dependence. Our present work suggests a convenient and practical route to design a highly efficient thermal rectifier by increasing the cellular size gradient or using materials with larger thermal conductivity to temperature ratios.

Obtaining of biomorphic composites based on carbon materials

Abstract Aim of this paper is to present the properties of carbon preforms for the production of biomorphic composites. Carbon samples were obtained through pyrolysis of paulownia wood, replicating the microstructure of the cellulosic precursor. Many characterization methods such as Raman Spectroscopy, light microscopy, hardness tests and pore size analyzer detection were used to investigate the microstructure of the product as well as the pore size of carbon samples. Obtained results showed that the parts of early or late wood template play an important role in the pore size, specific surface area and pore volume of the product. This review aims to be a comprehensive description of the development of carbon chars: from wood templates and their microstructure to potential applications of biomorphic materials.

Low-cost Ca-based composites synthesized by biotemplate method for thermochemical energy storage of concentrated solar power

An ever more environmentally conscious society demands the use of green, sustainable and high-efficiency renewable energy resources. However, large-scale energy storage remains a challenge for a deep penetration of power produced from renewables into the grid. The Calcium-Looping (CaL) process, based on the reversible carbonation/calcination of CaO, is a promising technology for thermochemical energy storage (TCES) in Concentrated Solar Power (CSP) plants. Natural limestone to be used as CaO precursor is cheap, non-toxic and abundant. Nevertheless, recent works have shown that carbonation of CaO derived limestone at optimum conditions for TCES is limited by pore-plugging, which leads to severe deactivation for large enough particles to be employed in practice. In our work, we have synthesized inexpensive CaO/SiO2 composites by means of a biotemplate method using rice husk as support. The morphological and compositional features of the biomorphic materials synthesized help improve the CaO multicycle activity under optimum CSP storage conditions and for particles sufficiently large to be managed in practical processes.

Effect of hydro-thermal carbonisation on the structural properties of bulk-type wood (Chamaecyparis obtusa) upon high-temperature heat treatment

Hydro-thermal carbonisation (HTC) is a method to convert biomorphic materials such as wood to carbon, with the advantage of enhancing their specific surface area to an extent greater than that by pyrolysis. In this study, wood samples underwent HTC at 250 °C, followed by a heat treatment at 600, 800 or 1000 °C. The cell walls of the HTC processed samples showed a structure made of alternating porous and dense carbon layers that changed as a function of the additional heat-treatment temperature. The specific surface area of the samples which underwent only a pyrolysis carbonisation drastically decreased at 80 °C, while that of the HTC samples was 473 m2/g, which enabled them to maintain a high-temperature stability. Compressive strength tests demonstrated plastic deformation and a different fracture mode for the HTC samples compared to the samples subjected to pyrolysis carbonisation only. Different values of mechanical strength in longitudinal and vertical directions were analysed.

Effect of activation on the porous structure and the strain and strength properties of beech wood biocarbon

The effect of activation on the size, specific volume, and surface area of pores in a monolithic biomorphic material obtained by carbonization of beech wood is studied. It is shown that under optimal activation mode with a steam heated to 970°C, the total pore volume and surface, determined by adsorption curves, increased by 20 and 18 times, respectively. With the use of high-precision interferometric procedure, strain curves are obtained under uniaxial compression with a stepwise loading, and the strain rate is measured with a step of moving of 325 nm for activated and nonactivated samples. Despite an increase in porosity, the strength and maximum deformation of the samples do not decrease. The behavior of the strain rate jumps is analyzed in the micro- and nanometer range. It is shown that the maximum size of the micrometer jumps (4 μm) correlates well with the average size of the possible strain area in the samples (the average distance between the pores of small size), and the minimum dimensions of the strain jumps are close to the size of mesopores. Assessment of the strain change and its rate upon activation indicates that the effect of activation on the strain and strength characteristics is defined by nanometer defects, the most likely of which are microand mesopores.

PHOTOCATALYTIC EFFICIENCY OF TiO2 IN BIOTEMPLATES FORM IN THE DECOLORATION OF ORGANIC DYE AND INHIBITION OF E. COLI GROWTH

Anatase TiO2 is widely used for pollutant degradation due to its photocatalytic property. Exposure of the surface to UV radiation (sunlight or artificial) generates an electron-hole pair that is responsible for the formation of free radicals such as O2•−in the presence of atmospheric oxygen and HO• in the presence of water. Biomorphic TiO2 plates were produced by infiltration of paper with titanium isopropoxide (TTiP) solution followed by hydrolysis in NH4OH and calcination at temperatures up to 600-1000 ºC, as a new way of fixing TiO2 with the aim of delaying the phase transition from anatase (photoactive) to rutile (inactive). In order to study the effect of addition of zirconia as a dopant on the microstructure and the phase transition from anatase to rutile, the same procedure was used, but with the addition of 5% (m/m) of ZrO(NO3)2 to TTiP. The biomorphic materials were characterized by XRD, specific surface area measurement (using the BET method), EPR, and SEM. Their photocatalytic efficiencies were evaluated in the decoloration of Orange II dye and the inhibition of growth of E. coli bioluminescent bacteria. Using 5% Zr-doped TTiP, with calcination at 800 ºC, bacterial growth was reduced by 23% after 180 minutes, and 70% dye decoloration was achieved in30 hours.

Biogenic and bio‐structured inorganic materials in heterogeneous catalysis: a brief overview

AbstractThis mini‐review highlights some research results related to the production and application of biogenic and biomorphic materials in catalysis. Such approaches are of interest for the preparation of materials of unusual and well defined morphology, as well as the recovery of valuable resources from waste streams. Areas covered are the application of biogenic iron oxide occurring as a natural waste in the form of iron ochre which can cause issues in water management, the application of biogenic manganese oxide materials formed from manganese rich media (and therefore possibly playing a role in water remediation), the application of bacteria for the preparation of metal nanoparticles of potential relevance to precious metal recovery from waste streams and the application of natural biological materials as templates for biomorphic inorganic materials of controlled and unusual uniform morphology. © 2015 Society of Chemical Industry

Biomorphic Materials: Silicon Carbide Derived from Natural Carbon Precursors

The recent initiative to cater toward an environmentally ef cient lifestyle has put pressure on many industries and practices. However, the success of these green initiatives has not been an easy achievement. During the past decade, scientists and engineers have worked tirelessly to discover a more natural way to process Silicon Carbide (SiC). A new category of materials, called biomorphic materials, has provided insight into how materials can be synthesized from bio-organic materials while retaining similar properties and performance. 1 In comparing SiC with its biomorphic cousin, BioSiC, there are notable similarities and differences in the properties, structure, processing, performance, and environmental concerns between each material discussed in this article.

Kinetics of liquid phase cyclohexene hydrogenation on Pd–Al/biomorphic carbon catalysts

The biomorphic mineralization technique is a powerful tool that allows to synthetize inorganic materials using as templates some structures of biological origin. This work presents kinetics results obtained during the liquid-phase hydrogenation of cyclohexene using a novel Pd–Al catalyst supported on biomorphic carbon.The catalysts have been prepared by a reactive method, using cellulose as carbonaceous precursor of the biomorphic support. The influence of the time and decomposition temperature (600–800°C) of cellulose under hydrogen atmosphere has been studied. The characterization results indicate that the synthesis of these biomorphic materials produce solids with high microporosity. The metallic dispersion of the Pd nanoparticles is strongly dependent on the preparation conditions (i.e. heating rate, thermal decomposition temperature and time) of the carbonaceous precursor.The kinetic study has covered the effect of the hydrogen pressure and temperature, and was carried out using a real-time in situ Raman probe. The developed kinetic model considers the non-competitive adsorption between hydrogen and cyclohexene in two different types of Pd metallic sites. The model explains all the experimental results obtained, providing a rational explanation for the variation of the kinetic orders and apparent activation energy obtained using the empirical power-law model.

Morphology-controlled fabrication of hierarchical LDH/C microspheres derived from rape pollen grain

BackgroundHierarchically structured LDH based materials are being actively investigated due to their potential applications in separation and catalysis which result from their fascinatingly porous features, tunable structures and properties. ResultsIn this study, we present a versatile, simple and reproducible method to fabricate hierarchical LDH/C microspheres by combining the biological template method (for Al2O3/C) and hydrothermal method (for LDH/C). To do this, the Al2O3/C microspheres are prepared by a biotemplating route using natural rape pollen grains as both the carbon source and the template. The LDH/C microspheres with hierarchical architectures are designed by in situ growth of nanoscaled LDH platelets on the microscaled carbon spheres. ConclusionThis new class of composite materials and the design strategies can be extended for the fabrication of other hierarchical biomorphic materials by using biological templates for separation and purification, catalysis, adsorption, and energy storage applications.

Preparation and Application of Morph Genetic Materials in the Field of Environment

Morph genetic material is a kind of new material which can not only keep natural biological fine morphology and structure but also is given new characteristics and functions. At present, the main preparation methods for biomorphic materials are chemical solution impregnation method, sound chemical processing method, and nanocomposite solvent heating method, etc. Domestic and foreign researchers have been trying to use different templates to prepare for functional materials which have different tendencies. Compared with the conventional artificial materials, these materials show obvious superiority. Morph genetic material is a new type of functional materials, mainly used as catalyst and adsorbent, playing an important role in environmental protection.

Biomorphic Ceramics Based on Biological Structures

Biomorphic ceramics is a novel inorganic materials with hierarchical structures derived from natural biological structures. In this paper, the properties of biomorphic materials are described. The preparation technologies of converting biological structures into biomorphic ceramics are summarized. At last the application and prospects of the ceramics in this field also are analyzed.