Catalytic Hydrolysis Research Articles

Deep removal of COS by carbon aerogel in natural gas: A 3D network structure of nitrogen doped and Cu based adsorbent

For the purpose of overcoming the difficulty of low removal rate of COS at low temperatures, N-doped copper oxide-supported carbon aerogels were prepared with sodium alginate as a carbon source for deep removal of COS (about 20 ppm) from natural gas. By exploring the effects of different nitrogen sources (urea, melamine and p-phenylenediamine), carbon–nitrogen ratio and carbonization temperature, p-phenylenediamine-doped copper oxide-loaded carbon aerogels (PPD-Cu/CA) with both excellent catalytic hydrolysis of COS and adsorption were prepared. The COS adsorption capacity of optimized PPD-Cu/CA was 18.6 mg·g−1 with 0.94 %Vol of water content at 40 °C, meanwhile, the COS removal efficiency at 40,000 and 70,000 mL·g−1·h−1 could reach 100 % and 94.6 %, respectively, showing excellent high space velocity resistance. Combined with characterization and experimental results, the introduction of p-phenylenediamine enriched the pore structure of the carbon carrier, increased the neutral base site, and played a positive role in the adsorption and hydrolysis of COS. This study provides a new insight into the removal of carbonyl sulfur from natural gas.

Catalytic hydrolysis of monochlorodifluoromethane over ZnO/ZrO2 catalysts at low temperatures.

Monochlorodifluoromethane (HCFC-22) has been identified as a significant contributor to the depletion of the Earth's ozone layer, garnering considerable attention within the scientific community. Consequently, the investigation of Freon degradation has become a central focus of current research efforts. In this study, we opted to employ catalytic hydrolysis as it offers numerous advantages for the degradation of HCFC-22. Specifically, we prepared ZnO/ZrO2 catalysts with hexahedral rod-like structures through citric acid complexation. We examined the impact of various preparation conditions (such as the molar ratio of ZnO to ZrO2, calcination temperature, and calcination time) as well as catalytic hydrolysis conditions (including the amount of catalyst, total flow rate, and catalytic hydrolysis temperature) on the hydrolysis rate of HCFC-22. Characterization of the catalysts was performed using techniques such as XRD, SEM, EDS, TG-DTG, FTIR, N2 adsorption-desorption, CO2-TPD, and NH3-TPD. Our experimental findings revealed the optimal preparation conditions: a catalytic hydrolysis temperature of 100°C, a molar ratio of ZnO to ZrO2 of 0.7, a water bath temperature of 90°C, a roasting temperature of 400°C, and a roasting time of 4h. At a catalytic hydrolysis temperature of 100°C, the hydrolysis rate of HCFC-22 reached 99.81%, with the main hydrolyzed products being HCl, HF, and CO2.

A colorimetric sensing strategy based on chitosan-stabilized platinum nanoparticles for quick detection of α-glucosidase activity and inhibitor screening.

α-Glucosidase (α-Glu) is implicated in the progression and pathogenesis of type II diabetes (T2D). In this study, we developed a rapid colorimetric technique using platinum nanoparticles stabilized by chitosan (Ch-PtNPs) to detect α-Glu activity and its inhibitor. The Ch-PtNPs facilitate the conversion of 3,3',5,5'-tetramethylbenzidine (TMB) into oxidized TMB (oxTMB) in the presence of dissolved O2. The catalytic hydrolysis of 2-O-α-D-glucopyranosyl-L-ascorbic acid (AA-2G) by α-Glu produces ascorbic acid (AA), which reduces oxTMB to TMB, leading to the fading of the blue color. However, the presence of α-Glu inhibitors (AGIs) hinders the generation of AA, allowing Ch-PtNPs to re-oxidize colorless TMB back to blue oxTMB. This unique phenomenon enables the colorimetric detection of α-Glu activity and AGIs. The linear range for α-Glu was found to be 0.1-1.0 U mL-1 and the detection limit was 0.026 U mL-1. Additionally, the half-maximal inhibition value (IC50) for acarbose, an α-Glu inhibitor, was calculated to be 0.4769mM. Excitingly, this sensing platform successfully detected α-Glu activity in human serum samples and effectively screened AGIs. These promising findings highlight the potential application of the proposed strategy in clinical diabetes diagnosis and drug discovery.

Low Palladium‐Loading HY Zeolite Catalyzed Hydrolysis of Hydrosilanes to Silanols and Alkoxysilanes

AbstractA low palladium‐loading heterogeneous catalyst has been developed for the hydrolysis of hydrosilanes to silanols and alkoxysilanes under mild and neutral reaction conditions with broad substrate scope. After five recycling runs, this low palladium‐loading catalyst keeps good activity for this transformation.

Microbial-Driven Synthesis and Hydrolysis of Neohesperidin Dihydrochalcone: Biotransformation Process and Feasibility Investigation.

A novel yeast-mediated hydrogenation was developed for the synthesis of neohesperidin dihydrochalcone (NHDC) in high yields (over 83%). Moreover, whole-cell catalytic hydrolysis was also designed to hydrolyze NHDC into potential sweeteners, hesperetin dihydrochalcone-7-O-glucoside (HDC-G) and hesperetin dihydrochalcone (HDC). The biohydrogenation was further combined with whole-cell hydrolysis to achieve a one-pot two-step biosynthesis, utilizing yeast to hydrogenate C═C in the structure, while Aspergillus niger cells hydrolyze glycosides. The conversion of NHDC and the proportion of hydrolysis products could be controlled by adjusting the catalysts, the components of the reaction system, and the addition of glucose. Furthermore, yeast-mediated biotransformation demonstrated superior reaction stability and enhanced safety and employed more cost-effective catalysts compared to the traditional chemical hydrogenation of NHDC synthesis. This research not only provides a new route for NHDC production but also offers a safe and flexible one-pot cascade biosynthetic platform for the production of high-value compounds from citrus processing wastes.

Optimization of valence and crystal structure of nickel-cobalt composites for efficient catalytic hydrolysis of borohydrides

Borohydrides are promising for hydrogen storage applications owing to borohydride hydrolysis reactions (BHR) characterized by controlled hydrogen evolution. However, the understanding of electronic structure-activity relationships and macroscopic synthesis of transition metal-based catalysts remains challenging. Herein, we employed a high-gravity technique coupled with impregnation-phosphorization to prepare NiCo-P/O with homogeneous and small particle sizes. Experiments and characterizations reveal that the phosphorization procedure confers the material's ability to catalyze BHR by introducing low valence Ni and Co. The catalytic activity for BHR shows a strong dependence on the valence state. Besides, the particle size and crystal structure of the catalysts were optimized by modulating the high-gravity field, thus boosting the catalytic activity towards BHR. As a result, NiCo-P/O catalyzed BHR at 298 K could produce pure hydrogen at 2060 mL min−1 g−1. This work provides a valence-activity relationship insight and feasible macro-synthetic catalysis strategies for BHR.

Understanding the hydrolysis mechanism of cyanogen chloride on copper and chromium surfaces

AbstractCyanogen chloride (CNCl) is a highly toxic agent, but there is currently a lack of research on the catalytic hydrolysis reaction of CNCl on metal surfaces. The low efficiency and unclear mechanism of CNCl hydrolysis reaction have hampered the development and enhancement of protective equipment. In this work, we focused on investigating the adsorption behavior and hydrolysis mechanism of CNCl on copper and chromium surfaces through first‐principle methods. Our findings revealed the most stable adsorption configuration of CNCl on metal surfaces and its terminal flipping behavior during the hydrolysis process. Subsequently, we designed and studied a series of CNCl hydrolysis reaction pathways, primarily involving C‐terminal intermediates. Notably, the adsorption energy of CN* displayed strong linear scaling relationships with that of other key reaction intermediates, directly influencing the activity and selectivity of CNCl hydrolysis. By employing the adsorption energy expression based on the intrinsic properties of substrates and adsorbates, we extended them to identify the adsorption energies of various complex reaction intermediates involved in CNCl hydrolysis. This comprehensive understanding of the reaction mechanism on metal surfaces provides a theoretical foundation and innovative perspective for the further exploration of CNCl hydrolysis catalysts.

Mechanically Triggered Polymer Deconstruction through Mechanoacid Generation and Catalytic Enol Ether Hydrolysis.

Polymers that amplify a transient external stimulus into changes in their morphology, physical state, or properties continue to be desirable targets for a range of applications. Here, we report a polymer comprising an acid-sensitive, hydrolytically unstable enol ether backbone onto which is embedded gem-dichlorocyclopropane (gDCC) mechanophores through a single postsynthetic modification. The gDCC mechanophore releases HCl in response to large forces of tension along the polymer backbone, and the acid subsequently catalyzes polymer deconstruction at the enol ether sites. Pulsed sonication of a 61 kDa PDHF with 77% gDCC on the backbone in THF with 100 mM H2O for 10 min triggers the subsequent degradation of the polymer to a final molecular weight of less than 3 kDa after 24 h of standing, whereas controls lacking either the gDCC or the enol ether reach final molecular weights of 38 and 27 kDa, respectively. The process of sonication, along with the presence of water and the existence of gDCC on the backbone, significantly accelerates the rate of polymer chain deconstruction. Both acid generation and the resulting triggered polymer deconstruction are translated to bulk, cross-linked polymer networks. Networks formed via thiol-ene cross-linking and subjected to unconstrained quasi-static uniaxial compression dissolve on time scales that are at least 3 times faster than controls where the mechanophore is not covalently coupled to the network. We anticipate that this concept can be extended to other acid-sensitive polymer networks for the stress-responsive deconstruction of gels and solvent-free elastomers.

A photoelectrochemical aptasensor for omethoate determination based on a photocatalysis of CeO2@MnO2 heterojunction for glucose oxidation

In the present work, we developed a photoelectrochemical aptasensor to determine omethoate (OMT) based on the dual signal amplification of CeO2@MnO2 photocatalysis for glucose oxidation and exonuclease I-assisted cyclic catalytic hydrolysis. CeO2@MnO2 heterojunction material prepared by hydrothermal method was linked with captured DNA (cDNA) and then assembled on the ITO conductive glass to form ITO/CeO2@MnO2-cDNA, which exhibited significant photocurrent response and good photocatalytic performance for glucose oxidation under visible light irradiation, providing the feasibility for sensitive determining OMT. After binding with the aptamer of OMT (apt), the formation of rigid double stranded cDNA/apt kept CeO2@MnO2 away from ITO surface, which ensured a low photocurrent background for the constructed ITO/CeO2@MnO2-cDNA/apt aptasensor. In the presence of target OMT, the restoration of the cDNA hairpin structure and the exonuclease I-assisted cyclic catalytic hydrolysis led to the generation and amplification of measurement photocurrent signals, and allowed the aptasensor to have an ideal quantitative range of 0.01–10.0 nM and low detection limit of 0.0027 nM. Moreover, the aptasensor has been applied for selective determination of OMT in real samples with good precision of the relative standard deviation less than 6.2 % and good accuracy of the recoveries from 93 % to 108 %. What's more, the aptasensor can be used for other target determination only by replacing the captured DNA and corresponding aptamer.

Ceria-Catalyzed Hydrolytic Cleavage of Sulfonamides.

Nanoceria is a promising nanomaterial for the catalytic hydrolysis of a wide variety of substances. In this study, it was experimentally demonstrated for the first time that CeO2 nanostructures show extraordinary reactivity toward sulfonamide drugs (sulfadimethoxine, sulfamerazine, and sulfapyridine) in aqueous solution without any illumination, activation, or pH adjustment. Hydrolytic cleavage of various bonds, including S-N, C-N, and C-S, was proposed as the main reaction mechanism and was indicated by the formation of various reaction products, namely, sulfanilic acid, sulfanilamide, and aniline, which were identified by HPLC-DAD, LC-MS/MS, and NMR spectroscopy. The kinetics and efficiency of the ceria-catalyzed hydrolytic cleavage were dependent on the structure of the sulfonamide molecule and physicochemical properties of Nanoceria prepared by three different precipitation methods. However, in general, all three ceria samples were able to cleave SA drugs tested, proving the robust and unique surface reactivity toward these compounds inherent to cerium dioxide. The demonstrated reactivity of CeO2 to molecules containing sulfonamide or even sulfonyl (and similar) functional groups may be significant for both heterogeneous catalysis and environmentally important degradation reactions.

Highly Active and Robust Catalyst: Co2B-Fe2B Heterostructural Nanosheets with Abundant Defects for Hydrogen Production.

A high-performance and reusable nonnoble metal catalyst for catalyzing sodium borohydride (NaBH4) hydrolysis to generate H2 is heralded as a nuclear material for the fast-growing hydrogen economy. Boron vacancy serves as a flexible defect site that can effectively regulate the catalytic hydrolysis performance. Herein, we construct a uniformly dispersed and boron vacancy-rich nonnoble metal Co2B-Fe2B catalyst via the hard template method. The optimized Co2B-Fe2B exhibits superior performance toward NaBH4 hydrolysis, with a high hydrogen generation rate (5315.8 mL min-1 gcatalyst-1), relatively low activation energy (35.4 kJ mol-1), and remarkable cycling stability, outperforming the majority of reported catalysts. Studies have shown that electron transfer from Fe2B to Co2B, as well as abundant boron defects, can effectively modulate the charge carrier concentration of Co2B-Fe2B catalysts. Density functional theory calculations confirm that the outer electron cloud density of Co2B is higher than that of Fe2B, among which Co2B with high electron cloud density can selectively adsorb BH4- ions, while the electron-deficient Fe2B is favorable for capturing H2O molecules, therefore synergistically promoting the catalytic NaBH4 hydrolysis to produce H2.

RuCo@P Core-Shell Nanoparticles Filled with Carbon Nanotubes for Highly Effective Catalytic Hydrolysis of Ammonia Borane

The doping of nonmetals in multiphase metal catalysts can effectively improve the catalytic performance and reduce the catalyst cost. In this study, we synthesized transition metal phosphide (RuCo@P/CNT) catalysts loaded on carbon nanotubes (CNT) using sodium borohydride (NaBH4) as the reducing agent. The microstructure and phase composition of RuCo@P/CNT nanoparticles were investigated using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and BET. RuCo@P/CNT nanoparticles show superior catalytic activity and cycle stability in the catalytic ammonia borane hydrolysis process compared to Ru/CNT and RuCo/CNT nanoparticles, retaining 65.74% of their initial catalytic activity after 5 reaction cycles. The test yielded values for turnover frequency and activation energy of 327.33 min-1 and 36.77 kJ·mol-1, respectively. Additionally, a kinetic isotope effect value of 2.61 for H2O/D2O showed that O-H bond breaking in proportional acceptor water is the decisive step in the dehydrogenation of ammonia borane, and based on this discovery, a specific mechanism for the catalytic hydrolysis of AB by RuCo@P NPs is postulated.

Reaction of NaBH4 and NaB(OH)4 as a way to increase the yield of hydrogen in catalytic hydrolysis of sodium borohydride by water

In this work, sodium tetrahydroxoborate (NaB(OH)4) that is the main product of the hydrolysis reaction of NaBH4 with a relatively small excess of water is studied in the reaction with sodium borohydride in the presence of a catalyst and without it. It was found, that mixtures consisting of NaB(OH)4 and NaBH4 begin to melt at 70 °C with the formation of a liquid phase without destroying the close coordination environment for both types of boron atoms. When a cobalt-based catalyst is added to mixtures, significant hydrogen evolution is observed. The resulting products are hydrogen and amorphous borates with a gross composition close to [NaBO2·0.75H2O].Carrying out the catalytic hydrolysis of borohydride in the system of initial composition H2O:NaBH4:catalyst under the conditions same to that the catalytic reaction of NaBH4 and NaB(OH)4 was observed is a promising way to produce H2 since it provides a high yield of hydrogen at small amounts of catalyst and atmospheric pressure. Catalytic hydrolysis carried out in the temperature range 80–120 °C with initial molar ratios H2O:NaBH4 = 3 and 2.7, and atmospheric pressure demonstrates a hydrogen yield of 8.3 wt% and NaBH4 conversion of 96 % at only 2.3 wt% of CoCl2 as catalyst. Since the resulting final composition of borates is close to [NaBO2·0.66H2O], the potential mass yield of hydrogen in this process can reach 9.3 wt%.

Basic property and oxygen defect-enhanced nitrogen-doped layered hydroxide-derived oxides MAlO (M = Ni, Co) for carbonyl sulfide hydrolysis at low temperature

Catalytic hydrolysis has been considered the most efficient method for the removal of carbonyl sulfide (COS). However, high-efficiency catalyst was urgently desired. In the present work, nitrogen-doped layered hydroxide-derived oxides (Ni(Co)Al-N) were successfully prepared. It was revealed that N enriched basic sites and oxygen vacancies were well developed for the prepared catalyst. And the catalytic activity was improved significantly. Among the catalysts, the NiAl-N catalyst exhibited the best catalytic activity (can reach 780 min COS 100 % conversion) and lowest activation energy. The concept of OH generation potential was firstly proposed to evaluate the contribution of basic sites to the improvement of catalytic activity. The OH generation potential was greatly improved due to N doping. More importantly, the enhanced basic property and oxygen defect content jointly contributed to the enhancement of catalytic activity. Besides, COS cannot adsorb on the catalyst surface and the reaction obeyed an E-R mechanism. Namely, H2O first adsorbed on basic sites to form OH groups, then COS reacted directly with the formed OH groups, and to generate H2S and CO2 products. HCO3– and HSCO2− were the main intermediate species, and the rate-determining step was the reaction between OCOSH* and H* to form CO2 and H2S.

Catalytic hydrolysis of methyl mercaptan and methyl thioether on hydroxyl-modified ZrO2: a density functional theory study.

The purification and removal of organic sulfur from natural gas is conducive to increasing the added value of natural gas and reducing environmental pollution. In this study, the adsorption properties of methyl mercaptan (CH3SH), dimethyl sulfide (C2H6S) and H2O on the surface of hydroxyl-modified ZrO2 were investigated using density functional theory (DFT) calculations. Additionally, a reaction mechanism was proposed for hydroxyl-modified ZrO2 catalyzing the hydrolysis of CH3SH and C2H6S. The chemisorption of H2O molecules on the catalyst surface is attributed to H-O and H-Zr bonds. The chemisorption of CH3SH and C2H6S on the catalyst surface is attributed to Zr-S bonds. Competitive adsorption between the three gases exists only between CH3SH and C2H6S. It reveals the water-resistant properties of hydroxyl-modified ZrO2 in desulfurization. The adsorption energies of the three gas molecules on the hydroxyl-modified ZrO2 surface are in the order of CH3SH - (Zr) > C2H6S - (Zr) > H2O - (OH). The natural hydrolysis of CH3SH and C2H6S is a heat-absorbing process that cannot occur spontaneously. The rate-determining step for CH3SH catalytic hydrolysis is the formation of CH3O. The fracture of CH3SHO is the rate-determining step for C2H6S catalytic hydrolysis. The depletion of the surface hydroxyl groups can be replenished by the dissociation of H2O molecules. Hydroxyl-modified ZrO2 facilitated the hydrolysis process of CH3SH to a greater extent than that of C2H6S. This study provides theoretical guidance for industrial applications and the design of hydroxyl-containing hydrolysis catalysts.

A novel experimental approach for the catalytic conversion of lignocellulosic Bambusa bambos to bioethanol

Bambusa bambos (B.B) biomass is cellulose rich lignocellulosic material, containing 47.49% cellulose, 17.49% hemicellulose, 23.56% lignin was used as a potential substrate for bioethanol production. The research paper investigates the use of B.B biomass as a substrate for bio-ethanol production through a two-phase catalytic conversion process. Four water-regulated regimes were identified to optimize the conversion of lignocellulosic biomass to biofuel precursors. The catalytic hydrolysis of B.B using CuCl2 was conducted for 10 hours at 110˚C, in aprotic ionic liquid (1-Butyl-3-methylimidazolium chloride) medium. The concentrations of glucose and 5-hydroxymethylfurfural (5-HMF) were measured while varying the amount of water addition. Water played a crucial role in the conversion of cellulose to glucose and 5-HMF by influencing product yields through the interplay of transport properties like heat conduction and viscosity. The highest glucose yield was achieved at 60.82% when operating at a water inclusion rate of 115.72 µL water/h for a duration of 6 hours at 110˚C. On the other hand, the maximum HMF yield was observed as 5.84% at water inclusion rate of 77.15 µL water/h for 5 hours at 110˚C. Yeast mediated glucose fermentation resulted in a bioethanol concentration of 5.5 mg/mL utilizing 15 mg/mL of catalytically produced glucose at a temperature of 30°C. After catalytic hydrolysis, the ionic liquid was also efficiently recycled for a sustainable economy.

Facile preparation of UiO-66-NH2-stabilized high internal phase molecularly imprinted polymers for synergistic catalytic hydrolysis detoxification of organophosphate nerve agents

Developed a UiO-66-NH2 stabilizing pickering high internal phase OP imprinting polymer multi-porous composite catalysis system, which integrates MIPs and MOFs successfully, the two materials with remarkable catalytic hydrolysis activity for OPs.

Techno-enviro-economic analysis of second-generation bioethanol at plant-scale by different pre-treatments of biomass from palm oil waste

This study evaluates three pathways: supercritical water treatment (SCW), CO2-water (scCO2-H2O), and catalytic hydrothermal hydrolysis (CHH) to produce second-generation bioethanol using palm tree fronds (PTF) as feedstock. The analysis focuses on technical performances using process simulation with Aspen Plus™, environmental evaluation by applying a Life Cycle Assessment (LCA) framework and an economic analysis using the levelized cost. The results of the technical performances reveal CHH as the best pathway for bioethanol production, with the highest ethanol yield at 273 L/tonne dry PTF and a substantial NER of 2.2, outperforming SCW and scCO2-H2O. From an environmental evaluation, CHH reveals lower carbon footprints of 61 g CO2 per MJ. Economically, CHH is competitive, with an ethanol production cost of1.11 $/L, comparable to the enzymatic hydrolysis process. These findings provide the technical, environmental, and economic aspects of a promising route for lignocellulosic bioethanol production while suggesting pathways for further optimisation for future research.

Mechanism and experimental study of bimetallic solid catalysts on urea catalytic hydrolysis to ammonia

Mechanism and experimental study of bimetallic solid catalysts on urea catalytic hydrolysis to ammonia

Comparative analysis of Zn(II)-complexes as model metalloenzymes for mimicking Jack bean urease.

The inhibitory action of Schiff base complexes of 3d metals against the urease enzyme is well explored in the scientific community. However, the ability of such complexes in mimicking active metallobiosites of urease enzymes, possessing ureolytic behavior, still remains unexplored. With this aim firstly, two Zn(II)-complexes (PPR-HMB-Zn and PZ-HMB-Zn) have been developed from two different Schiff base ligands (HL1 = 2-((E)-(2-(piperidin-1-yl)ethylimino)methyl)-5-methylphenol and HL2 = 2-((E)-(2-(piperizin-1-yl)ethylimino)methyl)-5-methylphenol) and structurally characterized using single crystal XRD. The hydrolytic enzymatic activity of both complexes was demonstrated by the gradual increase in the absorption maxima at 425 nm for the formation of the p-nitrophenolate ion from catalytic hydrolysis mediated by the Zn(II) complexes with a disodium salt of p-nitrophenyl phosphate as a model substrate. Associated kinetic parameters, pH dependency and a relevant hydrolysis mechanism have also been explored. After confirming the hydrolytic ability, the complexes were exploited to mimic the hydrolytic activity of Jack bean urease that catalytically hydrolyses urea into ammonia and CO2. The change in the pH of the solution owing to the formation of ammonia under the complex catalysed hydrolytic action of urea has been monitored spectrophotometrically using the pH dependent structural change of phenol red. The amount of ammonia has been quantified using the Nessler's reagent spectrophotometric method. The ureolytic reaction mechanism has been investigated using density functional theory (DFT) calculations using the B3LYP and TPSSH methods for the systematic calculation of the interaction energy. In contrast to PZ-HMB-Zn, PPR-HMB-Zn functions more effectively as a catalyst due to the existence of a lattice-occluded water molecule in its crystal structure and the protonation of the non-terminal N to attract urea by H-bonding, which was further confirmed by AIM analysis.