Precursor Composition Research Articles

Synthesis of Lithium-Nickel-Cobalt-Manganese-Aluminum Oxide-Based Ni-Rich Lib Cathode through Slug-Flow Manufacturing Platform

Lithium ion batteries (LIBs) with high specific capacity and long cycle life is critically required for high energy applications, such as electric vehicle technology. Owing to the high capacity, various Ni-rich cathodes (with Ni-content ≥ 80 %), including lithium-nickel-cobalt-manganese (NCM), lithium-nickel-cobalt-aluminum (NCA)-based layer oxides are widely explored to fabricate high performance LIBs.1 However, increase in Ni-content in the layered oxides aggravated the issues like, poor rate capability and short cycling performance due to the extensive volume contraction/expansion and the phase change above 4.2 V vs. Li/Li+. One rational strategy to achieve both high capacity and high mechanical stability for the Ni-rich cathodes is optimized doping of Al in the NCM moiety. Presence of Mn and Al in the same structure ensures high mechanical as well as thermal stability of the lithium-nickel-cobalt-manganese-aluminum oxide (NCMA).2 The performance of NCMA largely depends on the atomic percentage of each transition metals in the crystal structure. Hence proper control over the elemental composition and morphology is critically required. Among the various synthesis methods, stirred tank reactor-based co-precipitation synthesis through batch or semi-batch process is commonly used to synthesize phase pure NCMA precursors. However, the stirred tank reactor-dependent synthesis of battery precursors suffers from intrinsic batch-to-batch composition variability, increased agglomeration/breakage of particles and scaling up issues.The main goal of our research is to develop a low-cost scalable manufacturing platform for Ni-rich cathodes.3 Herein, we have utilized three-phase slug-flow reactor to produce NCMA oxalate precursor particles with high phase purity, homogeneity in composition and uniformity in particle size distribution (Figure 1). Here, the growth of precursor particles follows the co-precipitation chemistry and each of the self-circulating slugs works as the milliliter scale reactors, which offers better mixing of various reagents of the reaction mixture.3 The reactor is advantageous in terms of selective feeding of components, spatially uniform reaction conditions with high production rate and good control over the precursor composition and particle size, which further determines the tap density of the final material.4 In this work, NCMA oxalate with the compositional variation of Co= 6 – 10 % are synthesized through slug-flow, followed by high temperature lithiation of the precursor at high temperature of 750 oC in oxygen flow to obtain the final oxide material. The ammonium oxalate was used as the primary precipitation agent and ammonium hydroxide plays the roles of pH-controller as well as works as the chelating agent. The as-synthesized NCMA shows a high specific capacity of ~196 mAh g-1 at 0.1 C. The battery performance of the NCMAs are further analyzed by rate capability and cycling performance profiles. References Muralidharan, E. C. Self, M. Dixit, Z. Du, R. Essehli, R. Amin, J. Nanda, I. Belharouak, Adv. Energy Mater. 2022, 12, 2103050.H. Kim, L. Y. Kuo, P. Kaghazchi, C. S. Yoon, Y. K. Sun, ACS Energy Lett. 2019, 4, 576−582.B. Gupta, M. Jiang, M. Mou, A. Patel, J. H. Mugumya, S. Mallick, H. Lopez, M. p. Paranthaman, 2022 Meet. Abstr., MA2022-02, 25. DOI 10.1149/MA2022-02125.Jiang, Z. Zhu, E. Jimenez, C. D. Papageorgiou, J. Waetzig, A. Hardy, M. Langston, R. D. Braatz, Crys. Growth Des. 2014, 14, 851-860.Mou, A. Patel, S. Mallick, J. Mugumya, M. L. Rasche, M. P. Paranthaman, H. Lopez, G. P. Pandey, R. B. Gupta and M. Jiang, ACS Omega 2022, 7, 46, 42408–42417. Figure 1

Ultramicroporous N-Doped Activated Carbon Materials for High Performance Supercapacitors

Porous carbon electrode materials are utilized in supercapacitors with very fast charge/discharge and high stability upon cycling thanks to their electrostatic charge storage mechanism. Further enhancement of the performance of such materials can be achieved by doping them with heteroatoms which alter the kinetics of charge/discharge of the adsorbed species and result in pseudocapacitance phenomena. Here, microporous N-doped activated carbons were synthesized by thermochemical activation process. The structure and composition of the final material were adjusted by tuning the synthesis conditions and the choice of precursor molecules. In particular, N-doped activated carbons with a controlled specific surface area in the range of 270–1380 m2/g have been prepared by KOH-activation of sucrose/ammonium citrate mixture. By adjusting the composition of precursors, N-doping was varied from ca. 1.5 to 7.3 at%. The role of the components and synthesis conditions on the composition and structure of final products has been evaluated. The N-doped activated carbon with optimized structure and composition has demonstrated an outstanding performance as electrode material for aqueous electrolyte supercapacitors. The specific capacitance measured in a 3-electrode cell with 0.75 mg/cm2 loading of optimized activated carbon in 1M H2SO4 changed from 359 F/g at 0.5 A/g charging rate to 243 F/g at 20 A/g. Less than 0.01% of capacitance loss has been detected after 1000 charging/discharging cycles.

Effects of precursor compositions on the performance of inorganic perovskite CsPbI3 thin films and solar cells

Effects of precursor compositions on the performance of inorganic perovskite CsPbI3 thin films and solar cells

Preparation and Photocatalytic Degradation Performance of Amine-Rich Carbon Nitride with Structural Modulation of the Precursor.

The photocatalytic performance of graphitic phase carbon nitride (g-C3N4) is strongly influenced by its own microstructure as well as the precursor structure that causes the microstructure changes. In this paper, a composite precursor of sodium chloride and cyanamide (NaCl/CA-2) was obtained by freeze-drying, which possess an aggregated state different from that of the non-freeze-drying method. This new aggregation state with the introduction of sodium ions into the cyanamide lattice results in a higher activation energy of NaCl/CA-2 in the thermal polycondensation process of the molten salt-assisted preparation of g-C3N4, which prevented the condensation of two cyanamides to one dicyandiamide, ultimately obtaining FD-CN with an amino-rich structure. The nitrogen atoms on the amino group can provide the photocatalyst with more unpaired electrons that can participate in the photoexcitation process, further improving its electron-hole separation ability and charge transfer efficiency, thus effectively enhancing its photocatalytic activity. Compared to the original g-C3N4, the photocatalytic activity of FD-CN for the degradation of methylene blue increased 2.19 times.

Synergistic mesoporous bimetallic gold-silver nanoparticles: Synthesis, structure, and superior electrocatalytic activity

Mesoporous bimetallic nanoparticles have gained immense interest due to their unique properties and applications in various fields. In this study, we report a novel and straightforward one-pot chemical reduction method for the synthesis of mesoporous AuAg nanoparticles, featuring a substantial mesopore size (>10 nm) and a well-defined structure. The synthetic route involves employing L-cysteine as a ligand to form thiolate-metal(I) complexes and co-reduction of metal precursors around sacrificial templates of polymeric micelles. The resulting nanoparticles exhibit remarkable uniformity in size and possess a well-ordered mesoporous structure. Structural analyses confirm the formation of an alloy system containing Au and Ag without any distinct phases. By adjusting the initial precursor composition, precise control over the Au:Ag ratios in the final products is achievable. The electrocatalytic activity of mesoporous AuAg nanoparticles in the electrooxidation of small molecules surpasses that of mesoporous Au nanoparticles, owing to the synergistic effect arising from both the alterations in the electronic structure and the benefits offered by the porous architecture. This synthetic approach provides a promising avenue for developing efficient and cost-effective mesoporous Au-based nanoparticles for a diverse range of applications.

Relating the microstructural and glass transition temperature evolution of a carbon–carbon composite precursor during pyrolysis using thermomechanical analysis

AbstractPolybenzoxazine thermoset resins exhibit significant potential as precursors for carbon–carbon composites, owing to their high char yield upon pyrolysis. During pyrolysis, the resin is converted to an amorphous carbon‐rich material through a series of mechanisms, resulting in a linear increase of the glass transition temperature (TG) from 133 to 396°C at 0.48 pyrolytic conversion. To better understand this relationship, a non‐isothermal kinetic model was integrated, enabling the prediction of the TG onset, inflection, and endpoint based on the heat treatment protocol (process temperature (TP) vs. time) and the total volume of pyrolytic gases generated. By considering the TG behavior and anticipated gas effects, three distinct mechanisms were identified: (1) gas accumulation and matrix expansion leading to increased sample thickness (TG < TP), (2) crack network formation caused by gas‐pressure‐induced brittle failure (TG > TP), and (3) sample thickness reduction due to gas venting through the crack network (TG < TP). To validate this theory, thermal mechanical analysis was performed during pyrolysis, and changes in thickness (±ΔL/L0) were attributed to gas pressure‐related matrix deformation. Conversely, no change in ΔL/L0 indicated the formation of an interconnected crack network through which gases could vent without building a measurable internal pressure.

Uniform Composition of Sol-Gel Synthetic Aluminosilicate Precursor as a Key Factor for the Production of Geopolymers

This paper aims to study the fabrication of geopolymers from precursors synthesized by the sol-gel process. Two precursors were produced: the first one from a physical mixture of silica and alumina synthesized separately by the sol-gel technique, and the second one from a one-step co-condensation sol-gel process. The sol-gel products and a commercial metakaolin were activated with sodium hydroxide and sodium silicate to produce the geopolymers. The physically-mixed precursor did not lead to enough hard geopolymers, thus presenting a rubbery behavior. However, the geopolymers derived from the one-step sol-gel aluminosilicate reached adequate strength at 28 days with a lower density than from the commercial metakaolin. This confirms the good alkaline activity of this sol-gel precursor, which could be an alternative source to produce geopolymers or to be used as a reinforcement additive. Such results also underline that a uniform composition of the precursor is a key factor to produce geopolymers with adequate properties.

Tailoring the micro- and nanostructure of polymer-derived ceramic papers

Through the pyrolysis of cellulose-based paper templates infiltrated with a suitable polymer precursor, ceramic composites exhibiting a paper-like structure can be conveniently prepared. Such polymer-derived ceramic papers (PDCPs) unite the unique morphology of regular cellulose papers with the properties of the ceramic system utilized. Here, two paper templates, made from eucalyptus and cotton, respectively, were infiltrated with two polysilazane-based polymer precursors modified with either Fe, Ni, or Pd and converted into multi-phasic ceramic papers. In addition to the type of paper template, precursor composition, and transition metal used, the present study aims to rationalize the influence of pyrolysis temperature and atmosphere on the morphology, microstructure, and phase composition of the ceramic papers generated. For this purpose, scanning electron microscopy, SEM, and (scanning) transmission electron microscopy, (S)TEM, in conjunction with EDS analyses were used to elucidate the microstructural features of the ceramic composites in great detail. It is shown that the transition metals precipitate as nanosized metallic particles and silicides in the case of Pd and Ni, while the introduction of Fe features oxide and carbide phases in addition to that. Moreover, the metals catalyze both the graphitization of the cellulose fibers and, at higher temperatures, the generation of whisker-like Si-based nanostructures composed of either SiC or Si3N4, depending on the processing atmosphere used.

Physical, hydrolytic, and mechanical stability of alkali-activated fly ash-slag foam concrete

Foam concrete is prone to instability during mixing, casting, and curing. Besides preformed foam stability characteristics and volume, several geopolymer mix parameters, viz., precursor composition, silica modulus, alkali content, and water content, influence the overall foamed concrete stability, the understanding of which is still limited. This study evaluates the effect of the above parameters on the physical, hydrolytic, and mechanical stability of fly ash and slag-based foamed geopolymer. Physical stability was assessed by the design of experiments using a central composite design (inscribed), while systematic laboratory experiments assessed hydrolytic and mechanical stability characteristics. The foamed geopolymer behavior is sensitive to silica modulus and solid alkali-to-binder ratio, showing maximum interaction effects for producing stable foamed geopolymer for i) target to actual fresh density difference and ii) settlement along the height. The water-to-binder ratio was the most significant factor affecting the homogeneity across the cross-section along the height.Further, the alkali and slag content significantly affected the hydrolytic and mechanical stability characteristics. An optimum proportion of slag content, silica modulus, solid alkali-to-binder ratio, and water-to-binder ratio is suggested for the maximum benefit of fly ash and slag-based foamed geopolymer. This study provides a framework for comprehensive stability assessment of foamed geopolymers and can aid in developing sustainable lightweight materials for industrial applications.

Construction of the hierarchical porous biochar with an ultrahigh specific surface area for application in high-performance lithium-ion capacitor cathode

Biochar with a highly accessible specific surface area can display a higher performance when it is used as the cathode of lithium-ion capacitors. Facing the complex composition and diversity of biomass precursors, there is a lack of a universally applicable method to construct hierarchical porous biochar controllably. In this work, a multi-stage activation strategy combining the feature of different activation methods is proposed for this target. To confirm the porous characteristic in prepared samples, N2 adsorption–desorption and transmission electron microscope were used. As the optimal sample, BC-P3K4S had the highest specific surface area of 3583.3 m2 g−1. Evaluated as the electrode for a lithium-ion capacitor, BC-P3K4S displayed a capacity of 139.1 mAh g−1 at 0.1 A g−1. After coupling it with pre-lithiated hard carbon, the full device exhibited a high energy density of 129.3 W h kg−1 at 153 W kg−1. The work outlined herein offers some insights into the preparation of hierarchical porous biochar from complex biomass by multistep activation method.Graphical

Small angle X-ray scattering of particle growth and structure in spray flame synthesis

Customized metal oxide nanoparticles are on increasing demand due to their high specific surface area coupled with their material properties. Spray flame synthesis (SFS) is able to produce such particles in high quantity and purity. However, the turbulent flame including droplets is a complex system. The analysis of the product is challenging due to the broad size distribution of the aggregated primary particles. Thus, this study combines small angle X-ray scattering (SAXS) with transmission electron microscopy (TEM) in order to gain valuable information about primary particle sizes and fractal properties. Insights about the particle formation is obtained by comparing the SAXS data of titanium oxide and iron oxide particles produced with a variety of precursors in different concentrations using two burner setups. Remarkably, all presented systems show a size distribution of the primary particle with two size fractions. The differences in the sizes and consequences for the gained information about the fractal dimensions are discussed in detail. This includes the overlap of scattering information and resolution limits. All particle structures include small particles of 5–8 nm pointing to a gas-to-particle pathway. The large particle fraction ranges from 35 to 320 nm depending on precursor composition and concentration. Their formation is likely linked to hydrolysis reactions of the precursor in spray droplets. For the aggregates, the fractal dimension of mass with values 1.6–1.8 point to diffusion-limited cluster aggregation which is typical for flame-made products. The evaluation of in situ studies with synchrotron radiation confirms the gas-to-particle pathway.

Mitigating Co Metal Particle Agglomeration and Enhancing ORR Catalytic Activity through Nitrogen-Enriched Porous Carbon Derived from Biomass

Biomass-derived porous carbon has gained significant attention as a cost-effective and sustainable material in non-noble metal carbon-based electrocatalysts for the oxygen reduction reaction (ORR). However, during the preparation of transition metal catalysts based on biomass-derived porous carbon, the agglomeration of transition metal atoms often occurs, leading to a notable decline in catalytic activity. In this study, we present a straightforward synthetic approach for the preparation of nitrogen-enriched soybean-derived porous carbon (Co@SP-C-a) as an electrocatalyst for the ORR. To achieve this, we employed a two-step method. In the first step, a chemical activator (KCl) was utilized to enhance the porosity of the self-doped nitrogen biomass carbon material. In the second step, a constant pressure drop funnel technique was employed to uniformly disperse bimetal cobalt/zinc-based zeolitic imidazolium frameworks (ZIF-L and ZIF-67) containing different metal ions (Zn2+ and Co2+) into the activated biomass carbon material. Subsequent high-temperature calcination of the ZIF-L and ZIF-67@SP-C-a composite precursor yielded the Co@SP-C-a catalyst. The obtained catalyst exhibited remarkable ORR activity in an alkaline solution (Eonset = 0.89 V, E1/2 = 0.83 V, JL = −6.13 mA·cm−2) and exceptional long-term stability. This study presents an effective strategy to prevent the agglomeration of metal nanoparticles when integrating them with biomass-based carbon materials, thus leading to enhanced catalytic performance.

Supermolecule-regulated synthesis strategy of general biomass-derived highly nitrogen-doped carbons toward potassium-ion hybrid capacitors with enhanced performances

Biomass-derived carbons are promising anodes in potassium-ion hybrid capacitors owing to their tunable structure and competitive cost-effectiveness. The intercalation of K+ ions into carbonaceous anode is a sluggish reaction due to the turbostratic structure and large radius of K+ ions, resulting in the inability to exploit its high capacity and high-rate capability. Nitrogen-doping strategy could enhance the K-ion storage performance by surface capacitive adsorption mechanism. Nevertheless, conventional nitrogen-doping strategies could only endow biomass-derived carbons with low nitrogen-doping levels (<10 at.%), owing to the general agglomeration issue of biomass molecules and the easy release of nitrogen dopant during carbonization. Herein, we proposed a supermolecule-regulated strategy, which enables the breakage of the agglomeration of lignin molecule and disperses lignin in Lewis alkali-acid coupled supermolecule through inter-molecule interactions between lignin and the supermolecule. The co-decomposition of supermolecule/lignin composite precursor could form a covalent-bonded graphitic carbon nitride/carbon intermediate, ensuring the high nitrogen doping level (17.0 at.%) in lignin-derived carbon. The obtained carbon anode delivered high reversible capacities and high-rate capability. All-carbon potassium-ion hybrid capacitors constructed by this carbon as both anode and cathode exhibited a high energy density and power density. This work proposes a general method for constructing highly nitrogen-doped carbon anodes with superior performances.

High‐throughput fabrication, structural characterization, and cellular interaction of compositionally diverse fish gelatin/polycaprolactone (PCL) nanofibrous materials

AbstractNanofibers made by blending natural and synthetic biopolymers have shown promise for better mechanical stability, ECM morphology mimicry, and cellular interaction of such materials. With the evolution of production methods of nanofibers, alternating field electrospinning (a.k.a. alternating current (AC) electrospinning) demonstrates a strong potential for scalable and sustainable fabrication of nanofibrous materials. This study focuses on AC‐electrospinning of poorly miscible blends of gelatin from cold water fish skin (FGEL) and polycaprolactone (PCL) in a range of FGEL/PCL mass ratios from 0.9:0.1 to 0.4:0.6 in acetic acid single‐solvent system. The nanofiber productivity rates of 7.8–19.0 g/h were obtained using a single 25 mm diameter dish‐like spinneret, depending on the precursor composition. The resulting nanofibrous meshes had 94%–96% porosity and revealed the nanofibers with 200–750 nm diameters and smooth surface morphology. The results of FTIR, XRD, and water contact angle analyses have shown the effect of FGEL/PCL mass ratio on the changes in the material wettability, PCL crystallinity and orientation of PCL crystalline regions, and secondary structure of FGEL in as‐spun and thermally crosslinked materials. Preliminary in vitro tests with 3 T3 mouse fibroblasts confirmed favorable and tunable cell attachment, proliferation, and spreading on all tested FGEL/PCL nanofibrous meshes.

Optimization and Isothermal Studies of Antibiotics Mixture Biosorption From Wastewater Using Palm Kernel, Chrysophyllum albidum, and Coconut Shells Biocomposite

The presence of persistent pharmaceutical products in water bodies is a significant problem that obstructs wastewater reuse. This study investigated the adsorption process for removing the recalcitrant antibiotics, including tetracycline (TC), ampicillin (AMP), and amoxicillin (AMOX) from an aqueous solution using a composite biosorbent made from a mixture of palm kernel shell (PKS), Chrysophyllum albidum (CAS), and coconut shell (CS). Simplex centroid design in the Design of Expert (12.0.1.0) was applied to optimize the percentage composition (20-55%) of the composite biosorbent precursor and to remove TC-AMP-AMOX mixtures from the aqueous solution in a batch study. The equilibrium data were fitted to 12 isotherm models and analyzed statistically. The maximum adsorption capacity of 9.12 mg/g, 8.66 mg/g, and 7.11 mg/g was achieved for TC, AMP, and AMOX, respectively, using the biocomposite biosorbent with an optimal mixture of 55% PKS, 20% CAS, and 25% CS. The adsorption behavior of TC, AMP, and AMOX was well-described by the Langmuir/Elovich isotherm (R2=1.000), Hill-DeBoer (R2=0.9953), and Freundlich/ Halsey (R2=0.9898) models, respectively. The obtained results showed that the biocomposite PKS-CAS-CS leverages the individual adsorptive capacity of each constituent to enhance the adsorption process. Moreover, the composite biosorbent demonstrated excellent potential for removing recalcitrant pharmaceuticals from wastewater effectively.

Lowering oxygen content on the surface of Si/C composite anode material of lithium-ion batteries with calcium carbide

The inevitable oxidation of the surface increases the resistance of silicon (Si) as well as impairs its electrochemical performance as the anode of lithium-ion batteries (LIBs). The oxygen content of the Si/C composite surface is effectively reduced by using calcium carbide (CaC2) as a reductant in CaCl2-NaCl molten salt. The Si(O)/C-X (X: synthesis temperature) composite precursors are designed and synthesized by the oxidation of the industrial CaSi2 with the excess CaCO3 in molten CaCl2-NaCl, then the precursors are deoxidized to form the Si/C-X@C-Y (Y: reduction temperature) with lower oxygen content. The oxygen content of the Si/C-650@C-600 composite surface can be reduced by about 30 % compared to that of Si(O)/C-650. The rate performance and specific capacity of the Si/C-X@C-Y anode are significantly better than those of Si(O)/C-X. The Si/C-650@C-600 exhibits excellent rate performance with a capacity of 950.87 mAh·g−1 at 2 A·g−1, which is 74.4 % of its average capacity at 200 mA·g−1. Additionally, the Si/C-650@C-700 composite shows a capacity retention of 84.5 % after 400 cycles at 0.8 A·g−1. Lowering the surface oxygen content of Si(O)/C composites by using CaC2 in the molten salt can significantly improve the cycling stability of Si/C materials by effectively reducing the side-reactions between the Si anode and the electrolyte.

High-throughput thermodynamic analysis of the CVD of SiC from the SiCl4-CH4-H2 system

A high-throughput thermodynamic analysis based on the CALPHAD approach is employed in this study to gain insights into the chemical vapor deposition (CVD) of SiC from the SiCl4-CH4-H2 system using up-to-date thermodynamic databases. The explored deposition conditions, i.e., temperature, pressure, C/Si ratios and H2/SiCl4 ratios, ranges from 800 to 1800 °C, 400 to 40,000 Pa, 0.1 to 10 and 0.1 to 200, respectively. In addition to the metrics of deposit purity and deposition efficiency of SiC, a new metric, i.e., the utilization efficiency of precursors, is proposed in this work to facilitate the identification of the optimal deposition conditions. The influence of deposition parameters and precursor compositions on the compositions and phase stabilities of the condensed and gas phases pertinent to vapor processing are elucidated. The results show that the deposit purity is more sensitive to temperature than pressure. The optimal conditions to achieve high deposit purity (100 %), deposition efficiency (99.74 %) and the utilization efficiency of precursors (99.74 %) locate on the C/Si ratios between ~0.8 and ~ 1, H2/SiCl4 ratios above 8, low pressure (below 10 kPa) and medium temperatures (~ 1000 to ~1400 °C). Furthermore, low C/Si ratios (< 0.5) and high C/Si ratios (> 1) lead to the formation of free Si and graphite, respectively.

Landscape of Network Connectivity in Transient Polymer Networks with Competing Homo- and Hetero-complementary Bonds

Polymer networks expose a wide range of mechanical properties depending on their microstructure and connectivity. Specifically, transient networks based on end-linking of mixed telechelic polymer precursors capable of forming competing homo- and hetero-complementary bonds demonstrate a wide range of network structures and consequently mechanical properties depending on the composition and reactivity of employed precursors. To address this gap, the Miller–Macosko’s recursive model is extended to tetra-arm polymer precursors capable of forming homo- and hetero-complementary bonds. As such, the composition and time evolution of n-fold network connectivities are visualized as a function of precursor composition and bond selectivity. The model potential is highlighted by confronting its predictions with the rheological behavior of transient metallo-supramolecular polymer networks (MSPNs) obtained by mixing tetra-arm poly(ethylene glycol) functionalized with either sterically demanding mesitylene-substituted phenanthroline or unsubstituted slim phenanthroline or terpyridine ligands. The former precursor is incapable of homoleptic complexation; however, in combination with the latter two, they can form a mixture of homo- and heteroleptic complexes, depending on the coordination geometry preference of the utilized metal ion. These results not only visualize the connectivity landscape that can be explored in transient polymer networks, even beyond MSPNs, but can also provide a selectivity index for competing transient bonds based on rheological properties.

One-pot ternary sequential reactions for photopatterned gradient multimaterials

One-pot ternary sequential reactions for photopatterned gradient multimaterials

The flavour of grape colour: anthocyanin content tunes aroma precursor composition by altering the berry microenvironment.

Anthocyanin-less (white) instead of black/red (coloured) fruits develop in grapevine cultivars without functional VviMYBA1 and VviMYBA2 genes, which conditions the colour of wines that can be produced. To evaluate whether this genetic variation has additional consequences on fruit ripening and composition, we performed microenvironment, transcriptomics and metabolomics comparisons of developing grapes between near-isogenic white- and black-berried somatic variants of Garnacha and Tempranillo cultivars. Berry temperature was up to 3.5ºC lower in white- compared to black-berried Tempranillo. An RNA-seq study combined with targeted and untargeted metabolomics revealed that ripening fruits of white-berried variants were characterized by the upregulation of photosynthesis and other light-responsive genes and their higher accumulation of specific terpene aroma precursors, fatty acid-derived aldehyde volatiles and phenylpropanoid precursor amino acids. MYBA1-MYBA2 function proved essential for flavonol trihydroxylation in black-berried somatic variants, which were also characterized by enhanced pathogen defence gene expression in berry skin and increased accumulation of C6-derived alcohol and ester volatiles and GABA. Collectively, our results indicate that anthocyanin depletion entails side effects on grape composition by altering the berry internal microenvironment and the partition of the phenylpropanoid pathway. These findings show how fruit colour can condition other fruit features, such as flavour potential and stress homeostasis.