Biomass Catalysis Research Articles

Polyoxometalates@Metal-Organic Frameworks: Synthesis Strategies, Nanostructure Modulation and Application in Biomass Conversion.

Polyoxometalates@metal-organic frameworks (POMs@MOFs) have attracted much attention as multifunctional materials in biomass catalysis. Individual POMs and MOFs are hindered by their respective defects, such as poor stability and single catalytic active site, which make it difficult to realize large-scale applications. However, the combination of POMs and MOFs can be used to maximize the catalytic advantages of each. MOFs with high specific surface area and rich pore structure can effectively stabilize and uniformly disperse POMs, while the introduction of POMs also provides more catalytic possibilities for POMs@MOFs. Therefore, POMs@MOFs with ultra-high porosity, large specific surface area and excellent acid catalytic activity have unique catalytic advantages in the field of biomass catalytic conversion. In this work, we provide an overview of the current development of POMs@MOFs in the field of biomass catalysis. The synthesis strategies of POMs@MOFs are summarized and discussed, highlighting the in-situ synthesis methods. We focus on the nanostructure engineering of POMs@MOFs, and explore the "structure-property" relationship in depth. In addition, the representative work of POMs@MOFs in the catalysis of biomass derivatives is summarized. Filially, the prospects, and challenges for the future development of POMs@MOFs in the field of biomass catalysis are also presented.

Highly Efficient and Selective Hydrodeoxygenation of Guaiacol Using Ni-Supported Honeycomb-Structured Biochar and Phosphomolybdic Acid.

The sustainable development of energy has always been a concern. Upgrading biomass catalysis into hydrocarbon liquid fuels is one of the effective methods. In order to upgrade biomass derivative guaiacol by Hydrodeoxygenation (HDO) catalysis, this article report a three-dimensional honeycomb structure biochar loaded with Ni nanoparticles and phosphomolybdic acid demonstrating excellent catalytic performance in a short period of time. This is due to the porous structure of biochar, which allows Ni metal nanoparticles to be highly uniformly dispersed on the support, which enhances the catalytic hydrogenation of guaiacol in terms of both rate and efficiency. Furthermore, it was observed that the added phosphomolybdic acid dissolved within the temperature range of 78-90 °C, functioning as a homogeneous catalyst in the process. This proves advantageous, as the phosphomolybdic acid becomes accessible at any location within the porous Ni/C catalyst. The detailed characterization data revealed that the carbon support prepared in this study has a high specific surface area of up to 1375.61 m2/g. Additionally, the phosphomolybdic acid exhibited rich acidity, with Brønsted and Lewis acid contents of 2.55 μmol/g and 21.45 μmol/g, respectively. Reaction data demonstrated that at 240 °C for 180 min, 100 % conversion and 97.9 % cyclohexane selectivity were achieved. This study introduces a bifunctional catalyst with an unique catalyst's structure, facilitating a heterogeneous-homogeneous catalytic reaction and delivering an efficient catalytic effect.

Influence of binder selection on the catalytic performance of zeolite-based bifunctional catalysts for biomass catalysis

The impact of binder selection on catalytic performance of real catalyst extrudates is still limitedly shown in biomass catalysis. Herein, we have prepared two zeolite-based bifunctional extrudates (Ni/LaY-Al2O3 and Ni/LaY-SiO2). Compared with Ni/LaY-Al2O3, Ni/LaY-SiO2 shows a markedly enhanced durability and sustained performance for 936 h in the continuous liquid-phase hydrogenation of γ-valerolactone into methyl pentanoate. Complementary characterization studies reveal that choosing SiO2 as binder could efficiently mitigate metal agglomeration, coke formation and support dealumination during catalysis. These findings showcase that binder selection is essential for catalyst durability in the development of the industrial-level bifunctional catalysts for biomass valorization.

Recent Advances in Zeolites-Catalyzed Biomass Conversion to Hydroxymethylfurfural: The Role of Porosity and Acidity.

Biomass is an attractive raw material for the production of fuel oil and chemical intermediates due to its abundant reserves, low price, easy biodegradability, and renewable use. Hydroxymethylfurfural (5-HMF) is a valuable platform chemically derived from biomass that has gained significant research interest owing to its economic and environmental benefits. In this review, recent advances in biomass catalytic conversion systems for 5-HMF production were examined with a focus on the catalysts selection and feedstocks' impact on the 5-HMF selectivity and yield. Specifically, the potential of zeolite-based catalysts for efficient biomass catalysis was evaluated given their unique pore structure and tunable (Lewis and Brønsted) acidity. The benefits of hierarchical modifications and the interactions between porosity and acidity in zeolites, which are critical factors for the development of green catalytic systems to convert biomass to 5-HMF efficiently, were summarized and assessed. This Review suggests that zeolite-based catalysts hold significant promise in facilitating the sustainable utilization of biomass resources.

Experimental study on thermophysical property of deep eutectic solvents as heat transfer fluid

Deep eutectic solvents are now widely used in metal electrochemical deposition, biomass catalysis and material synthesis because of their advantages of greenness, low cost, good biocompatibility and biodegradability, and it is proved that DESs have great potential for its utilization as heat transfer fluids. In this work, eight DESs were prepared by thermal method using choline chloride as the hydrogen bond acceptor and glycerol, polyethylene glycol 600, lactic acid and o-cresol as the hydrogen bond donor. Based on the flow calorimetry method, the specific heat capacity system was established and its reliability and precision were verified by measuring the specific heat capacity of deionized water. The maximum deviation of the experimental value and the standard value under the pressure 101 kPa was 2.03%, and the average absolute deviation was 1.01%, and the repeatability was less than 1.5%. Then, the densities and the constant pressure specific heat capacities of eight DESs in the temperature range of 293 K–353 K and 293 K–373 K were measured respectively. The experimental results could support for the scale utilization of DESs.

Efficient synthesis of furfural from waste biomasses by sulfonated crab shell-based solid acid in a sustainable approach

As one of key biobased chemicals, furfural can be manufactured from the hydrothermal transformation of hemicelluloses in biomass, which is widely utilized in manufacturing furans, plastics, polymers, rubbers, resins, synthetic fibers, medicine, biofuels and other additives. In this work, one eco-friendly and sustainable approach for transforming waste lignocellulosic biomass to furfural was established in one-pot reaction manner. Crab shells (CRSs), which are derived from discarded seafood bio-waste, are known as one kind of naturally renewable and abundant bioresource. Using the pretreated CRS as support, a biobased heterogeneous chemocatalyst Sn-CFCRS was successfully prepared by carbonization followed by sulfonation, which was utilized to transform waste lignocellulosic biomass into furfural. The structure and morphology of the as-prepared chemocatalyst was examined and the acidity was measured. Deep eutectic solvent choline chloride:malic acid (DES ChCl:MA) (pKa=3.46) was chosen to assist Sn-CFCRS for catalysis of biomass. The catalytic performances were evaluated by one-pot transformation of various biomasses to furfural. Sn-CFCRS (2.4 wt%) transformed 75 g/L corncob into 117.1 mM furfural (65.6% yield) at 180 °C after 10 min in ChCl:MA−water (1:9, v/v) containing 50 mM CaCl2. This established sustainable process shows high potential application for valorization of biomass into furfural by utilizing biobased chemocatalyst in a benign reaction medium.

An Efficient Strategy for Chemoenzymatic Conversion of Corn Stover to Furfuryl Alcohol in Deep Eutectic Solvent ChCl:PEG10000−Water Medium

As a versatile and valuable intermediate, furfuryl alcohol (FOL) is widely utilized in manufacturing vitamin C, perfume, fruit acid, lubricant, lysine, plasticizer, dispersing agent, resin, fuel additive, and biofuel. This study aimed at the establishment of a cascade catalysis of biomass to FOL via a hybrid approach in a deep eutectic solvent medium. The catalysis of corn stover (75 g/L) with solid acid AT-Sn-WLS (1.2 wt%) produced 110.5 mM FAL in a ChCl:PEG10000–water (20:80, wt/wt) system at 170 °C for 30 min, and then the formed FAL was biologically transformed into FOL with recombinant E. coli SF harboring aldehyde reductase at pH 7.0 and 35 °C. This established hybrid strategy could efficiently valorize corn stover into FOL, with the productivity of 0.41 g FOL per g xylan in corn stover. Consequently, one combination of chemocatalytic and biocatalytic reactions leading to a one-pot catalytic process was shown as an attractive approach in the valorization of lignocellulose into valuable biobased chemicals.

Zeolitic Imidazolate Framework Decorated Molybdenum Carbide Catalysts for Hydrodeoxygenation of Guaiacol to Phenol

Bimetallic zeolitic imidazolate framework (BMZIF)-decorated Mo carbide catalysts were designed for the catalytic hydrodeoxygenation of guaiacol to produce phenol with high selectivity. A uniform layer of BMZIF was systematically coated onto the surface of the MoO3 nanorods. During carbonization at 700 °C for 4 h, BMZIF generated active species (ZnO, CoO) on highly dispersed N-doped carbons, creating a porous shell structure. Simultaneously, the MoO3 nanorod was transformed into the Mo2C phase. The resulting core@shell type Mo2C@BMZIF-700 °C (4 h) catalyst promoted a 97% guaiacol conversion and 70% phenol selectivity under 4 MPa of H2 at 330 °C for 4 h, which was not achieved by other supported catalysts. The catalyst also showed excellent selective cleavage of the methoxy group of lignin derivatives (syringol and vanillin), which makes it suitable for selective demethoxylation in future biomass catalysis. Moreover, it exhibits excellent recyclability and stability without changing the structure or active species.

An efficient chemoenzymatic strategy for valorisation of corncob to furfuryl alcohol in CA:Betaine-water

Biobased chemical furfuryl alcohol is an important furfural-upgrading compound, which is mainly used to prepare fruit acids, resins, additives, polymers, fibers, and rocket fuels. In this study, one sustainable way for valorisation of biomass into furfuryl alcohol was developed via chemoenzymatic conversion in one-pot manner. Deep eutectic solvent (DES) CA:Betaine was prepared by mixing betaine and citric acid (CA). Using CA:Betaine (10 wt%) as catalyst and reaction medium, the carbohydrates (glucan plus xylan) in corncob (60 g/L) were firstly catalyzed to produce 74.6 mM furfural, 96.5 mM formic acid and 40.3 mM glucose at 170 °C for 30 min in CA:Betaine-water (10:90, wt:wt). Furthermore, co-expression of formate dehydrogenase (FDH) and NADPH-dependent aldehyde reductase (SsCR) from Sporidiobolus salmonicolor in one E. coli was a good strategy for the efficient biosynthesis of furfuryl alcohol. Within 2 h, E. coli SF21 efficiently converted corncob-derived furfural (74.6 mM) to furfuryl alcohol in a yield of 95.8 % by using corncob-derived formate and glucose as co-substrates. The furfuryl alcohol productivity was obtained at 0.117 g furfuryl alcohol/g corncob (0.343 g furfuryl alcohol/g xylan). Overall, this study provided a novel chemoenzymatic strategy for catalysis of biomass into furfuryl alcohol in CA:Betaine-water.

Valorization of Biomass to Furfural by Chestnut Shell-based Solid Acid in Methyl Isobutyl Ketone-Water-Sodium Chloride System.

Recently, highly efficient production of furfural from available, abundant, inexpensive, and renewable lignocellulosic biomass has gained much attention by using biomass-based heterogeneous catalyst in an effective biphasic system. Using microwave-treated chestnut shell (MC-CNS) as biobased support, biomass-based catalyst (MC-Sn-CNS) was firstly synthesized for catalyzing biomass into furfural. The structure parameters of MC-Sn-CNS were measured by BET, SEM, XRD, and FT-IR. After systematical optimization, furfural yield reached 64.4% from corncob by MC-Sn-CNS (3.6 wt%) at 180°C for 15min in methyl isobutyl ketone (MIBK)-water (2:1, v:v) containing 200mM NaCl. MC-Sn-CNS had high stability, which could be recycled for 7 batches. The yield of furfural from fresh corncob was 44.5-64.4%. The possible catalytic mechanism for synergistic catalysis of biomass to furfural by MC-Sn-CNS was expounded in MIBK-water-NaCl system. The results showed that green solvent (MIBK) and NaCl promoted the production of furfural from CC catalyzed by solid acid (MC-Sn-CNS). This study demonstrated an environmentally friendly strategy for efficiently utilizing corncob into furfural by CNS-based heterogeneous chemocatalyst in a green reaction media. Clearly, this newly synthesized biomass-based MC-Sn-CNS catalyst had potential application in the future.

Highly Efficient Chemoenzymatic Cascade Catalysis of Biomass into Furfurylamine by a Heterogeneous Shrimp Shell-Based Chemocatalyst and an ω-Transaminase Biocatalyst in Deep Eutectic Solvent–Water

Highly Efficient Chemoenzymatic Cascade Catalysis of Biomass into Furfurylamine by a Heterogeneous Shrimp Shell-Based Chemocatalyst and an ω-Transaminase Biocatalyst in Deep Eutectic Solvent–Water

Metal-alkali catalytic valorization of lignocellulose towards aromatics and small molecular alcohols and acids in a holistic approach

In this work, we developed an approach of one-pot complete catalytic conversion of woody biomass into two value product streams: lignin-derived aromatics (monomer yield of 68.54% and oligomer yield of 29.65% based on lignin mass) and (semi-)cellulose-derived small molecular alcohols (about 59.60% of biomass mass). These could be afforded by conducting lignocellulose depolymerization over metal-alkaline catalysts in a mixed n-butanol/H2O solvent system at 250 °C and 30 bar H2. In the valorization process, the homogenous mixture of n-butanol-H2O solvents extract and depolymerize both lignin and hemicellulose, while the catalysts and H2 are essential to cleave the inter-/intramolecular linkage of lignocellulose into target products. After the reaction, the phase separation of n-butanol and H2O takes place when system temperature drops below 125 °C, providing a mild and effective strategy to isolate lignin-derived aromatics (n-butanol phase) from small molecular alcohols/acids (aqueous phase). Ru/C and alkali catalysts are collected by filtration from n-butanol phase and H2O phase, respectively. Meanwhile, the effect of metal-alkali coupled catalysts facilitates the cleavage of β-O-4 linkage of lignin and increases the attainability of (semi-)cellulose-derived oligomers and the small molecular alcohols. This catalytic system provides a versatile valorization approach for biomass catalysis to bio-based chemicals.

Hot Research Topics in the Biomass Catalysis Section of the Catalysts Journal in 2018 and 2019

In recent years, many researchers have contributed to the “Biomass Catalysis” section of the journal Catalysts (MDPI) [...]

Chemoenzymatic Synthesis of Furfuryl Alcohol from Biomass in Tandem Reaction System.

In this study, chemoenzymatic synthesis of furfuryl alcohol from biomass (e.g., corncob, bamboo shoot shell, and rice straw) was attempted by the tandem catalysis with Lewis acid (SnCl4 or solid acid SO42-/SnO2-bentonite) and biocatalyst in one-pot manner. Compared with SnCl4, solid acid SO42-/SnO2-bentonite had higher catalytic activity for converting biomass into furfural, which could be biologically converted into furfuryl alcohol with Escherichia coli CCZU-H15 whole-cell harboring reductase activity. Sequential catalysis of biomass into furfural with SO42-/SnO2-bentonite (3.0 wt%) at 170 °C for 0.5 h and bioreduction of furfural with whole cells at 30 °C for 4.5 h were used for the effective synthesis of furfuryl alcohol in one-pot media. Corncob, bamboo shoot shell, and rice straw (3.0 g, dry weight) could be converted into 65.7, 50.3, and 58.5 mM furfuryl alcohol with the yields of 0.26, 0.25, and 0.23 g furfuryl alcohol/(g xylan in biomass) in 40 mL reaction media. Finally, an efficient process of recycling and reusing of SO42-/SnO2-bentonite catalyst and immobilized whole-cell biocatalyst was developed for the chemoenzymatic synthesis of furfuryl alcohol from biomass in the one-pot reaction system.

Deep Eutectic Solvents for Pretreatment, Extraction, and Catalysis of Biomass and Food Waste.

Valorization of lignocellulosic biomass and food residues to obtain valuable chemicals is essential to the establishment of a sustainable and biobased economy in the modern world. The latest and greenest generation of ionic liquids (ILs) are deep eutectic solvents (DESs) and natural deep eutectic solvents (NADESs); these have shown great promise for various applications and have attracted considerable attention from researchers who seek versatile solvents with pretreatment, extraction, and catalysis capabilities in biomass- and biowaste-to-bioenergy conversion processes. The present work aimed to review the use of DESs and NADESs in the valorization of biomass and biowaste as pretreatment or extraction solvents or catalysis agents.

A dual acidic hydrothermally stable MOF-composite for upgrading xylose to furfural

This work presents the development of a new hybrid material composed of metal-organic-framework, MIL-101 (Cr) and mesoporous tin phosphate nanoparticles. The phosphate groups of the composite impart Brønsted acidity, while the Cr and Sn atoms act as the Lewis acid sites, thus promoting it as a dual acid functionalized material suitable for solid acid catalysis of biomass. Simultaneously, the issues of hydrothermal stability and degradation in acidic medium as faced by pristine MIL-101 (Cr), have been fairly alleviated. In order to demonstrate our claims, the composite has been used as a solid acid catalyst for the dehydration of xylose to furfural. A remarkable performance of 86.7% furfural yield with 92.3% selectivity has been achieved in 180 min at 150 °C. The composite can sustain minimum of 10 cycles of run while pristine MIL-101 (Cr) loses its functional properties after 4 cycles of run. In presence of 35 ppt NaCl solution, the yield and selectivity improved to 92.4% and 96.6% respectively.

Elastic Effects in Adsorbate–Adsorbate Interactions of C and S on a Stepped Ru Surface

We examine strain modification of adsorbate–adsorbate interaction in the (C*+S*)/fcc-Ru(211) system for relevance to biomass to hydrocarbon catalysis and the broader case of interaction changes under strain. Applied biaxial strains from −3% to +3% shift the C and S binding and interaction energies by ±0.3 eV for C and ±0.1 eV for S, binding and interaction being additive and leading to stronger binding with tension, creating larger total changes in binding for the covered surfaces. Changes in the near-neighbor interactions with strain are found to be primarily electronic in origin—there is little change in mechanical interaction. While mixing and thermodynamic analysis reveals that the C+S system will mix over the complete range of strains studied, the application of strain, whether tensile or compressive, may lead to reduced sulfur coverage. For biomass catalysis, the implication is that strain may be used to optimize hydrocarbon chemistry with only improvements in poisoning due to site blocking. It is a...

Recent progress of synthesis and applications in polyoxometalate and nanogold hybrid materials

The role of polyoxometalates (POMs) in the synthesis and stabilization of gold nanoparticles (Au NPs) is reviewed in light of many of the recent developments. The vitality of these hybrid materials is discussed with many examples of POMs and different synthesis techniques. Also, applications of these newly emerging hybrid materials in numerous fields such as electrocatalysis, photocatalysis, biomass catalysis, oxidation of alkenes, bio-sensing, and medicinal use are highlighted. Limitations in these applications are indicated, and areas of future applications that could be explored in these vast ranging hybrid materials are described.

Biomass Catalysis Pyrolysis for Furans Chemicals

In an effort to direction convert biomass by means of pyrolysis for fine chemicals as a substitute fuel, some inorganic matters were chosen to investigate the possibility of improving the catalysis of biomass pyrolysis. Inorganic acids are catalysts to be found effective for giving high selectivity to furfural chemicals.

Exploring Meerwein–Ponndorf–Verley Reduction Chemistry for Biomass Catalysis Using a First-Principles Approach

Liquid phase catalytic hydrogenation of decomposition products of sugar molecules is challenging, but essential to produce platform chemicals and green chemicals from biomass. The Meerwein–Ponndorf–Verley (MPV) reduction chemistry is an excellent choice for the hydrogenation of keto compounds. The energy landscapes for the liquid phase catalytic hydrogenation of ethyl levulinate (EL) and furfural (FF) by Sn(IV) and Zr(IV) zeolite-like catalytic sites utilizing the hydrogen atoms from an isopropanol (IPA) solvent are explored using quantum chemical methods. The computed apparent activation free energy for the catalytic hydrogenation of EL by a Sn(IV) zeolite-like catalyst model site is (21.9 kcal/mol), which is close to the Al(III)-isopropoxide catalyzed (20.7 kcal/mol) EL hydrogenation indicating the similar efficiency of the Sn(IV) zeolite-like catalyst compared with the Al(III) catalyst used in the traditional MPV reactions. The catalytic efficiency of metal isopropoxides for the catalytic hydrogenation of EL is computed to be Al(III) > Sn(IV) > Zr(IV) in IPA solution, in agreement with experiment. Calculations were also performed with furfuryl alcohol as the source for hydrogen for the conversion of EL to γ-valerolactone using the Sn(IV) catalytic site. The barrier (22.7 kcal/mol) suggests a hydrogenation using aromatic primary alcohol as a hydrogen donor and using a Sn(IV) catalyst is feasible. In terms of reaction mechanisms, an intramolecular hydride transfer through a six membered transition state was found to be the turnover controlling transition state of liquid phase catalytic hydrogenation of carbonyl compounds considered in this study.