Hydrolysis Performance Research Articles

Fast and selective production of quercetin and saccharides from rutin using microwave-assisted hydrothermal treatment in the presence of graphene oxide

Rutin is a flavonoid glycoside, well-known for its antioxidant, anticarcinogenic, and cardioprotective properties. However, it exhibits lower bio absorptivity and bioactivity than its aglycon form, quercetin. Although liquid acid catalysts are conventionally utilized to obtain quercetin via rutin hydrolysis, the neutralization procedure is a major disadvantage owing to the added cost. In this study, graphene oxide (GO) was used as an alternative catalyst under microwave (MW) irradiation, owing to its easy separation from the reaction solution and high MW absorptivity, resulting in improved thermal efficiency. Two types of GOs were prepared (GO-HU using Hummer’s method and GO-TO using Tour’s method), and their catalytic performance for rutin hydrolysis was evaluated and compared. The highest rutin conversion (98.8 %) and quercetin yield (81.9 %) were obtained at 180 °C when the reaction was conducted for 15 min using 3 mg of GO-TO and 2400 ppm of initial rutin concentration in 50 mL of water.

Ni/Ce co-doping δ-MnO2 nanosheets with oxygen vacancy for enhanced electrocatalytic oxygen evolution reaction

The design and manufacture of strongly engaged, low-cost, and resilient oxygen evolution reaction (OER) electrocatalysts is the most challenging task in electrochemical hydrolysis. Herein, Ce and Ni co-doped MnO2 (NiCe/MnO2) nanosheets (NSs) with oxygen vacancy (VO) and abundant active sites have been prepared in one step employing a defect strategy. The co-doping of Ce/Ni on the one hand reduced the catalyst particle size and increased the specific surface area, which promoted the exposure of more active sites. On the other hand, heteroatom doping altered the species the crystalline surface, stimulating the formation of Vo and thus activating the catalyst performance simultaneously. The OER performance of NiCe/MnO2 NSs was significantly enhanced over the pure δ-MnO2, with an overpotential of 170 mV (10 mA cm−2), which was verified by density functional theory. This work shows a straightforward and practical method for making non-precious metal electrocatalysts with high electrochemical hydrolysis performance.

The doped Co on Rh/Ni@Ni–N–C that weakened the catalytic performance for ammonia borane hydrolysis

Alloy catalyst has been widely studied and used for hydrolytic dehydrogenation of ammonia borane (NH3BH3, AB) with excellent catalytic performance due to the synergistic effect of bimetal. Herein, a series of Rh1-xCox/Ni@Ni–N–C catalysts were prepared by an impregnation reduction method. The optimized Rh0.75Co0.25/Ni@Ni–N–C catalyst exhibited good catalytic performance with turnover frequency of 223.08 molH2 molcat−1 min−1 at 303 K, but decreased the catalytic performance compared with Rh/Ni@Ni–N–C. According to the XPS and Raman analysis, the RhCo alloy nanoparticles could be loaded at the defect position of Ni@Ni–N–C, and the Co nanoparticles occupied the intercalation between Rh and the defective site of the carrier, which could weaken the catalytic activity of AB hydrolysis. Based on the above research, we proposed the catalytic mechanism of the activation of the RhCo–H species. This work provides a new strategy for designing alloy-supported nano-catalysts.

More than just a reactant: H2O promotes carbonyl sulfide hydrolysis activity over Ni-MgAl-LDO by inhibiting H2S poisoning

Sulfur poisoning was a bottleneck in the development of Carbonyl sulfide (COS) catalytic hydrolysis technology. Herein, the sulfur poisoning process over Ni-doped MgAl layered double oxide (Ni-MgAl-LDO) catalysts during COS hydrolysis was simulated by H2S processing and the effect of H2O on sulfur poisoning were investigated. H2S would be deposited on the weak and medium basic sites of Ni-MgAl-LDO, which lead to the catalyst poisoning and deactivation. The presence of excess water would inhibit COS hydrolysis performance over conventional catalysts, but interestingly, the poisoning effect of H2S on the Ni-MgAl-LDO catalyst was greatly suppressed with the introduction of H2O. H2O molecules were adsorbed and activated on the Ni-MgAl-LDO catalyst surface, which could inhibit the deactivation by promoting desorption of H2S. Therefore, H2O, not only as a reactant, but also as a protector, took part in the COS hydrolysis over the Ni-MgAl-LDO catalyst.

Active clusters ensemble effect of bimetallic RuCo alloys for efficient hydrogen production from ammonia borane

Bimetallic alloy nanoparticles (NPs) have proven to be an effective catalyst for hydrogen production from ammonia borane (AB) hydrolysis, but how to explain the relationship between bimetallic catalytic activity and the shape, size and dispersion of bimetallic components has always been a daunting challenge. In this paper, a trace Ru-based bimetallic RuCo alloy catalyst deposited on N-doped porous carbon nanosheets (NPC) was prepared through a simple impregnation reduction approach accompanied by the hydrolysis catalysis of AB. The activity of RuxCo1-x/NPC catalyst is mainly contingent on the composition of Ru and Co metals.The high catalytic activity of Ru0.075Co0.925/NPC can be ascribed to the fact that the active cluster ensemble effect of the bimetallic RuCo alloy exhibits the random stacking of rigid geometry and the structure of more d-electron layers without filling, which are conducive to its display of strange catalytic properties that bulk materials do not possess. Moreover, the co-alloying effect between Ru and Co NPs can dramatically improve the hydrolysis performance of AB. The present experimental study will provide a promising approach for high catalytic activity and have the potential of hydrolyzing hydrogen from chemical storage materials.

Hydrogen Generation from Mg Wastes by Cold Rolling and Ball Milling by Hydrolysis Reaction: Elektron 21 (UNS-M12310) in Simulated Seawater

Hydrolysis is an efficient way of producing hydrogen by using Mg-based waste. In this study, H2 production is realized in simulated seawater (i.e., 3.5 wt.% NaCl) using the Elektron21 (EL21) alloy as a reagent. This alloy is a magnesium-based alloy composed of 96 wt.% Mg and 4 wt.% rare earth (approx. 3 wt.% Nd and 1 wt.% Gd). EL21 is known for its excellent corrosion resistance and high tensile strength. The impact of different mechanical treatments (ball milling, cold rolling, cryo rolling, and cryo ball milling) on the hydrolysis yield of the material was discussed. A pretreatment with cryo rolling before ball-milling treatment shows the best hydrolysis performance, with a yield of 90.5% achieved in 10 min in salted water. The ductile-to-brittle transition induced a modification of the microstructure, which explains the good hydrolysis performances.

2-Naphthol modification alleviated the inhibition of ethanol organosolv lignin on enzymatic hydrolysis

It has been reported that the lignins deposited on surfaces of pretreated biomass directly affected the enzyme adsorption, thus impeding enzymatic hydrolysis of lignocellulose. Alleviating the surface lignin inhibition is urgently needed for establishing an efficient lignocellulose biorefinery process. In this study, ethanol organosolv lignins (EOLs) from masson pine and poplar were employed as representatives of surface lignins. Aiming to mitigate the EOLs inhibition on enzymatic hydrolysis, 2-naphthol as a carbocation scavenger was added in the organosolv pretreatment. The function of 2-naphthol for suppressing lignin condensation was verified by investigating the lignin structural changes with NMR analysis. Moreover, it was verified that 2-naphthol modification remarkably eliminated the negative effects of EOLs from both two wood species, leading to a 6.8–34.4% increase in hydrolysis yields. The effects of 2-napthol modified lignins were even reversed to slightly promote the enzymatic hydrolysis of pure cellulose. The mechanism of 2-naphthol modification for relieving lignin inhibition was revealed by evaluating the relationship between lignin structural features and hydrolysis performance with Pearson's correlation heatmap. Results enrich our understanding of surface lignin inhibition, thereby providing ideas for promoting enzymatic hydrolysis by alleviating the surface lignin inhibition.

Experimental and theoretical approach of the hydrolysis of pelleted magnesium alloys scraps

Industrial Mg alloys scraps containing 3% of Al and 3% of Zn (and about 20% of MgO and Mg(OH)2) were ball milled with the addition of 5 wt% C and 5 wt% of Ni, Cu, Co or SiO2. 3 h of ball milling were needed to obtain optimum hydrolysis performances of the mixtures (e.g. yields of almost 90% obtained within 1 min). Pellets of such obtained powder were prepared as it is easier for an application. The shape of the hydrolysis curves highlights first an incubation period depending on the compactness of the pellets and then a second part with a logarithmic shape. A new model is presented that allows to take into account both parts of the hydrolysis curve. The model is applied successfully to all the pellets having various compactness.

Synergistic hydrolysis of filter paper by recombinant cellulase cocktails leveraging a key cellobiase, Cba2, of Cellulomonas biazotea.

Cellulomonas biazotea, a Gram-positive cellulolytic bacterium isolated from soil, is capable of producing a complete cellulase complex exhibiting endoglucanase, exoglucanase, and cellobiase activities. Despite the presence of a full complement of all three types of cellulases, samples prepared from both cell lysates and culture media of C. biazotea showed only weak synergistic activities formed among the cellulase components, as reflected by their inefficient performance in filter paper hydrolysis. However, when the five previously characterized recombinant cellobiases of C. biazotea were mixed individually or in different combinations with recombinant enzyme preparations (CenA/Cex) containing an endoglucanase, CenA, and an exoglucanase, Cex, of another Cellulomonas species, C. fimi, the cellulase cocktails exhibited not only much higher but also synergistic activities in filter paper hydrolysis. Among the 5 C. biazotea cellobiases studied, Cba2 was shown to perform 2.8 to 3.8 times better than other homologous isozymes when acting individually with CenA/Cex. More noteworthy is that when Cba2 and Cba4 were added together to the reaction mixture, an even better synergistic effect was achieved. The filter paper activities resulting from Cba2 and Cba4 interacting with CenA/Cex are comparable to those obtained from some commercial fungal cellulase mixtures. To our knowledge, our results represent the first demonstration of synergistic effects on filter paper hydrolysis achieved using recombinant bacterial cellulases.

Green synthesis of pistachio shell-derived biochar supported cobalt catalysts and their catalytic performance in sodium borohydride hydrolysis

Pistachio shell-derived biochar supported cobalt catalysts were synthesized by using a modified impregnation-chemical reduction method. Polydopamine (PDA) and tannic acid (TA) were used as reducing and functionalizing agents. The effect of modification treatment was investigated on the physicochemical and catalytic properties. The peaks observed in XRD patterns belonged to biochar and cobalt. The surface area, total pore volume and pore diameter values of Co-PDA@BC catalyst were determined as 268 m2/g, 0.262 cm3/g and 3.03 nm, respectively. These values higher than that of Co-TA@BC catalyst. FTIR spectra exhibited bands representing the biochar structure. XPS spectra showed that cobalt was embedded in the support structure in metallic and oxide form. The use of PDA improved structural properties and catalytic activity of catalyst. The maximum hydrogen generation rate and activation energy for Co-PDA@BC was determined as 25 mL min−1gcat−1 and 31.3 kJ mol−1, respectively.

Coupling ultralow-content ruthenium with nickel hydroxide via corrosion engineering for highly efficient hydrogen generation from ammonia borane

Efficient and controllable release of hydrogen from solid hydrogen storage materials is a promising way to produce hydrogen safely and on-demand. The development of economical, highly active, easily recyclable catalysts is critical for practical applications, which remains a great challenging. Herein, the easily controllable and cost-effective corrosion strategy is ingeniously developed to simply prepare ultralow-content ruthenium coupled with nickel hydroxide on nickel foam (Ru–Ni–NF). After experiencing the spontaneous oxidation-reduction reactions between the reactive NF and Ru3+, ultrafine Ru nanoparticles decorated nickel hydroxide nanosheets are in situ intimately grown on porous NF networks. The optimal Ru–Ni–NF catalyst exhibits the excellent performance for catalytic hydrolysis of ammonia borane with a high turnover frequency (TOF) of 539.6 molH2 molRu−1 min−1 at 298 K and a low apparent activation energy of 36.4 kJ mol−1, due to the synergistic effect between Ru nanoparticles and nickel hydroxide nanosheets. Furthermore, the Ru–Ni–NF catalyst possesses easy separation and outstanding durability, which is superior to powdered catalysts. This study provides a facile and economical strategy for the preparation of ultralow-content noble metal supported metal foam-type catalysts for dehydrogenation of ammonia borane.

Geometric improvement of hydrolysis reactor structure to enhance the sustainable production of hydrogen from MgH2

Hydrogen is an important clean renewable energy carrier and has the advantages of high calorific value, low environmental impact, and wide availability. Magnesium hydride (MgH2) has attracted extensive attention due to its high hydrogen storage density; however, its poor hydrolysis kinetics limit its application. In this paper, the hydrolysis performance of MgH2 was studied in a self-made hydrolysis reactor, which included both a single tube structure and a plate tower structure. The hydrolysis reactor with the plate tower structure was conducive to achieving controllable and continuous MgH2 hydrolysis. Specifically, the plate tower structure can effectively strengthen the distribution of MgH2 materials, improve the liquid–solid mass transfer and reduce the surface coating. The results of this paper can expand the application of traditional reactors and provide a novel approach for the design of hydrolysis reactors for controllable continuous MgH2 hydrolysis.

Graphene-Modified Co-B-P Catalysts for Hydrogen Generation from Sodium Borohydride Hydrolysis.

Sodium borohydride (NaBH4) is considered a good candidate for hydrogen generation from hydrolysis because of its high hydrogen storage capacity (10.8 wt%) and environmentally friendly hydrolysis products. However, due to its sluggish hydrogen generation (HG) rate in the water, it usually needs an efficient catalyst to enhance the HG rate. In this work, graphene oxide (GO)-modified Co-B-P catalysts were obtained using a chemical in situ reduction method. The structure and composition of the as-prepared catalysts were characterized, and the catalytic performance for NaBH4 hydrolysis was measured as well. The results show that the as-prepared catalyst with a GO content of 75 mg (Co-B-P/75rGO) exhibited an optimal catalytic efficiency with an HG rate of 12087.8 mL min−1 g−1 at 25 °C, far better than majority of the findings that have been reported. The catalyst had a good stability with 88.9% of the initial catalytic efficiency following 10 cycles. In addition, Co-, B-, and P-modified graphene showed a synergistic effect improving the kinetics and thermodynamics of NaBH4 hydrolysis with a lower activation energy of 28.64 kJ mol−1. These results reveal that the GO-modified Co-B-P catalyst has good potential for borohydride hydrolysis applications.

Production and Functional Characterization of a Novel Mannanase from Alteromonadaceae Bacterium Bs31.

Mannans are the main components of hemicellulose in nature and serve as the major storage polysaccharide in legume seeds. To mine new mannanase genes and identify their functional characteristics are an important basis for mannan biotechnological applications. In this study, a putative mannanase gene (ManBs31) from the genome of the marine bacterium Alteromonadaceae Bs31 was characterized. Amino acid sequence analysis and protein structural modeling were used to reveal the molecular features of ManBs31. The catalytic domain of ManBs31 was recombinantly produced using Escherichia coli and Pichia pastoris expression systems. The biochemical properties of the enzymes were determined by reducing sugar assay and thin-layer chromatography. Sequence analysis revealed that ManBs31 was a multidomain protein, consisting of a catalytic domain belonging to glycoside hydrolase family 5 (GH5) and two cellulose-binding domains. Recombinant ManBs31-GH5 exhibited the maximum hydrolytic performance at 70 ºC and pH 6. It showed the best hydrolysis capacity toward konjac glucomannan (specific enzyme activity up to 1070.84 U/mg) and poor hydrolysis ability toward galactomannan with high side-chain modifications (with a specific activity of 344.97 U/mg and 93.84 U/mg to locust bean gum and ivory nut mannan, respectively). The hydrolysis products of ManBs31-GH5 were mannooligosaccharides, and no monosaccharide was generated. Structural analysis suggested that ManBs31-GH5 had a noncanonical +2 subsite compared with other GH5 mannanases. ManBs31 was a novel thermophilic endo-mannanase and it provided a new alternative for the biodegradation of mannans, especially for preparation of probiotic mannooligosaccharides.

Modulating valence band to enhance the catalytic activity of Co-Cr-B/NG for hydrolysis of sodium borohydride

In this work, amorphous Co-Cr-B/NG catalysts were prepared by the chemical reduction method. A descriptor of "valence band center" was introduced to the NaBH4 hydrolysis reaction to investigate the relationship between the valence band and the catalytic activity of amorphous Co-Cr-B/NG catalysts. The outcomes show that the valence band center of the Co-Cr-B/NG hybrids has been significantly changed after the Cr content is regulated by the preparation process, which can facilitate the modulation of the electronic structure of the catalysts. The hydrogen release rate shows a shape of a volcano with the valence band center. The hydrolysis performance test results of the optimum catalyst demonstrated that the hydrogen release rate of NaBH4 water at 25 °C was 2231.7 mL·min−1·g−1 with an activation energy of 38.41 KJ·mol−1, according to the volcano curve.

Introducing mesopore and regulating Al distribution for improving catalytic performances of ZSM-5 in furfuryl alcohol to levulinic acid

Catalytic valorization of biomass into chemicals and fuels plays a key role in order to achieve net-zero greenhouse gas emissions. Herein, a series of hierarchical ZSM-5 zeolites were synthesized by the post-treatment method to transform furfural alcohol (FAL) to levulinic acid (LA). ZSM-5 obtained from tandem alkaline treatment (0.2 M NaOH) and acid washing (0.1 M HCl), denoted as ZSM-5-OH0.2-H, exhibited the highest activity, affording 76.2% LA yield in 9:1 acetone–water mixed solvents at 393 K for 0.5 h. The enhanced adsorption capacity and acid accessibility of FAL on zeolite mediated by the introduction of mesopores, as well as the reduced secondary reactions of the generated LA due to few Al atoms in straight and sinusoidal channels (as confirmed by UV–vis diffuse reflectance), were responsible for the outstanding catalytic performance of ZSM-5-OH0.2-H. The structure–activity relationship revealed that regulating the porous structure and Al distribution of ZSM-5 was an effective strategy to enhance its hydrolytic performance of FAL to LA. Moreover, ZSM-5-OH0.2-H could be reused for three reaction cycles without significant loss in catalytic activity.

RETRACTED ARTICLE: Preparation of carrierized cellulase Cellulase@MIL-88B(Fe) and its enzymatic properties

We, the Editors and Publisher of Green Chemistry Letters and Reviews have retracted the following article: Erhong Zhang, Meng Wang, Xiaoliang Pan, Xinfeng Wang & Wenju Zhang (2022) Preparation of carrierized cellulase Cellulase@MIL-88B(Fe) and its enzymatic properties, Green Chemistry Letters and Reviews, 15:3, 627-637, DOI: https://doi.org/10.1080/17518253.2022.2124890 Following publication, the authors requested the withdrawal of this article in 2022 due to a conflict with an associated patent. Further investigations by the Publisher, in close collaboration with the Editor-in-Chief, could not confirm a conflict with an associated patent but revealed that the article has significant overlap with a chapter of an unpublished thesis titled “Construction of an adaptive immobilized cellulase system and its enzymatic hydrolysis performance” authored by Tiantian Li in June 2022. More specifically, the overlap involves most of the data in the article which was reused without the required permissions, or the knowledge of the owners of the data. Upon query, the authors have cooperated with the investigation, but could neither demonstrate that their data was obtained appropriately, nor that their study was conducted in compliance with our editorial policies. As the reuse of data from a third-party without acquiring the required permissions is a serious breach of publishing ethics, we are retracting the article from the journal. The corresponding author listed in this publication has been informed. We have been informed in our decision-making by our editorial policies and the COPE guidelines. The retracted article will remain online to maintain the scholarly record, but it will be digitally watermarked on each page as ‘Retracted’.

Efficient enzymatic hydrolysis of Protogracillin for clean preparation of Prosapogenin A by response surface methodology optimization

ABSTRACT Prosapogenin A (also known as Progenin III and polyphyllin V), a secondary steroidal saponin in Dioscorea zingiberensis tubers, has more superior pharmacological activities than its primary form Protogracillin. Conventional preparation methods, such as column chromatography, and acidic hydrolysis, are of very low efficiency and limited scale due to tedious procedures and large consumption of organic solvent. This study aims to establish a convenient method for efficiently obtaining Prosapogenin A by enzymatic hydrolysis of abundant Protogracillin in the raw material. In light of the highest hydrolysis performance, β-dextranase was selected from four commercial enzymes in this application. After optimization of the conditions by the response surface methodology using Box–Behnken design, the enzymatic hydrolysis was carried out in 0.20 M HAc-NaAc buffer (pH 4.81) containing β-dextranase/Protogracillin (5.0:1, w/w), and the system was constantly kept at 56.7°C water bath for 4 h. Consequently, Protogracillin has been almost completely hydrolyzed to be Prosapogenin A and the highest yield was 96.4 ± 1.4%. The newly proposed approach is efficient and promising for conveniently obtaining Prosapogenin A and aimed to provide a laboratory-scale experimental foundation for the preparation of Prosapogenin A in industrial applications.

Boosting COS catalytic hydrolysis performance over Zn-Al oxide derived from ZnAl hydrotalcite-like compound modified via the dopant of rare earth metals and the replacement of precipitation base

In this work, a series of Zn-Al oxides calcined from ZnAl hydrotalcite-like catalysts were prepared using the co-precipitation method and then applied to remove COS. The effects of the content of Sm and the species of rare earth metal on the catalytic activities of COS hydrolysis are investigated. Experimental results show that the prepared catalyst doped with 20 wt% Sm performs better catalytically. Based on the optimization of Sm dopant, the effect of the precipitation base in the ZnAl hydrotalcite-like compounds on the catalytic activities of the catalysts is further investigated. The results show that the prepared catalyst using KOH and K2CO3 as the precipitation base exhibits the best catalytic performance. The characterization results show that the doping of rare earth metals can weaken the crystallinity and the introduction of an appropriate amount of Sm ions can significantly enhance the proportion of adsorbed oxygen species. Moreover, the results show that the synergistic effect of the doping of Sm and the replacement of precipitating alkali contribute to the enhancement of the number of basic sites, especially weak and medium basic sites. Furthermore, combined with in-situ DRIFTS, the catalytic mechanism of COS hydrolysis on ZnAl-20Sm-Na MMO is proposed.

Antimony and boron support to aluminum's hydrolysis performance and an application of PEM fuel cell

In this study, Al-Sb-B (aluminum-antimony-boron) ternary alloys are designed to improve the hydrolysis performance in alkaline media through the corrosive effects of intermetallic Al-Sb and Al-B particles. The maximum hydrogen generation rate of an ASB1 (Al-2.97 wt% Sb-0.99 wt% B) alloy is 4.78 times higher than ASB0 (Al-3 wt% Sb) alloy and 8.36 times higher than pure Al at certain temperatures. While the average hydrogen generation rate (HR) of pure Al is 2.66 ml cm−2 min−1, ASB1 alloy's HR is reached up to 16.78 ml cm−2 min−1. This improvement is achieved by sweeping the Al surface with the convection effect of the secondary phase particles (Al-Sb and Al-B) caused by the temperature fluctuations during the exothermic reaction. At 323 K–343 K temperature range, the apparent activation energy (EA) is calculated as 50.2 kJ mol−1 for pure Al and the lowest EA is calculated as 33.7 kJ mol−1 in ASB0 alloy. A selected alloy is tested in a Proton Exchange Membrane (PEM) fuel cell to observe its system performance. ASB3 (Al-2.913 wt% Sb-0.913 wt% B) alloy is selected for the PEM fuel cell application experiments and 2.72 mW output power is obtained. Thanks to alloying Al with other metals, different power demands of a PEM fuel cell flow requirements may be optimized.