Industrial Catalysis Research Articles

Optimized modelling and kinetic analysis of nickel recovery from waste orthodontic implants using response surface methodology

With the increasing applications of nickel in industrial homogeneous catalysis, coatings, and batteries a large amount can be recycled from waste orthodontic implants that contain ∼ 10% nickel. This research has reported a cost-effective, low temperature, and environmentally friendly route for recovering nickel from the waste orthodontic implants using a hydrometallurgical technique. Response surface methodology coupled with central composition design (CCD) was employed to optimize and maximize the yield. Leaching time, temperature, rotational speed, and solid–liquid (S-L) ratio were considered independent parameters, while recovery of nickel was taken as a response. A quadratic regression model was developed for the maximization of nickel leaching concerning input parameters and response. Different performance indicators (i.e., RE, RMSE, and MAE) were employed to assess the developed model further. Based on ANOVA analysis, temperature, and S-L ratio were found to be statistically significant factors. The results show a maximum nickel yield of ∼95% was achieved with optimized parameters viz., temperature (90 °C), leaching time (180 min), rotational speed (40 rpm), and S-L ratio (1:50). Furthermore, the kinetic analysis of the process is also carried out using the Jander rate equation, and the calculated activation energy of nickel leaching with a first-order reaction is 39.8 kJ/mol.

The past and the future of catalysis and technology in industry: a perspective from Casale SA point of view

The role of catalysis in the chemical industry has always been essential. The word catalyst is derived from the Greek word katalύein, meaning “to dissolve” and in 1836 Jöns Jakob Berzelius defined it as “change caused by an agent which itself remains unchanged“. Most of the chemical processes such as NH3 and syngas production, catalytic cracking of gas oil, synthesis of sulfuric and nitric acid, are only possible thanks to catalysis. Therefore, catalysis has a huge and direct impact on the life of every human being. This work discusses what are the practical implications related to the availability of a catalyst for a company developing and selling technologies for the production of some of the most important chemicals. It offers also a perspective on the future evolution of catalysis and technology in chemical industries.

Recovery of Phosphoric Acid from Spent Petrochemical Catalysts

AbstractPetrochemical catalysts are widely used in the industry. For the production of cumene, zeolite‐based catalysts containing phosphoric acid are applied. Over the time, coking deactivates the surface, and the catalyst has to be exchanged and disposed of. Different process approaches for recycling the phosphoric acid‐containing catalysts were investigated. Related preliminary investigations have shown that calcination of the used catalyst is necessary prior to reprocessing. By digesting the catalyst with hydrofluoric acid, ∼96 % phosphate was recovered. However, this process is very costly in terms of process technology. More promising is digestion by basic or acidic routes. Several options are possible here, and digestion with H3PO4 proved to be particularly suitable. Here, phosphate yields reached up to 98.8 %, with a positive balance of economic efficiency at the same time. The catalyst can be produced and recycled in the same plant with the same reagents, what constitutes a major breakthrough towards sustainability in industrial catalysis.

High Performance Tunable Catalysts Prepared by Using 3D Printing.

Honeycomb monoliths are the preferred supports in many industrial heterogeneous catalysis reactions, but current extrusion synthesis only allows obtaining parallel channels. Here, we demonstrate that 3D printing opens new design possibilities that outperform conventional catalysts. High performance carbon integral monoliths have been prepared with a complex network of interconnected channels and have been tested for carbon dioxide hydrogenation to methane after loading a Ni/CeO2 active phase. CO2 methanation rate is enhanced by 25% at 300 °C because the novel design forces turbulent flow into the channels network. The methodology and monoliths developed can be applied to other heterogeneous catalysis reactions, and open new synthesis options based on 3D printing to manufacture tailored heterogeneous catalysts.

Hierarchically Hollow MnO2@CeO2 Heterostructures for NO Oxidation: Remarkably Promoted Activity and SO2 Tolerance

Thermochemical approaches of oxidizing NO to NO2 have been considered as the critical steps governing NOx purification technologies. However, developing efficient materials with boosted NO oxidation activity and strong SO2 resistance at low temperature still remains a significant challenge. This contribution discloses a versatile and scalable methodology for the design of hollow MnO2@CeO2 heterostructures for NO oxidation. Due to its hollow core–shell nanostructure with a high density of active oxygen vacancies and improved charge-transfer efficiency induced by the heterojunction interface, the resulting material exhibits remarkable low-temperature catalytic activity in NO oxidation (T50 at 196 °C and T92 at 275 °C), achieving over 69 °C of temperature reduction in comparison with the commercial Pt/Al2O3 catalyst (T50 at 275 °C). Remarkably, the SO2 tolerance of the hollow core–shell material is greatly enhanced due to the block accessibility of the mesoporous CeO2 shell (ECeO2,SO2 = −1.78 eV vs EMnO2,SO2 = −1.04 eV). This work exemplifies an alternative perspective in the design of high-performance hollow core–shell nanostructured catalysts for atmospheric pollutant purification and industrial thermal catalysis processes.

Nitrophenol Violet as a New Tool for Studying of Kinetics of Reactions in Solutions

This experimental lab set is for students taking college chemistry courses. It includes four laboratory works and completely illustrates the important parts of chemical kinetics, namely the determination of the rate constant and the determination of the factors influencing its value. They can be used in a laboratory set for a physical chemistry laboratory course, or separately, using only one or two of the four laboratory exercises for general, colloid, and organic chemistry laboratory courses, as well as biological and industrial catalysis. The experiment forms an understanding of the possibilities of controlling the reaction rate and an understanding of intermolecular interactions in solutions. The classical effects of the rate constant are considered, such as the effects of salt and solvent, as well as micellar catalysis. The main focus is on the following factors: increasing polarity of the medium or ionic strength decelerates the reactions between Dyez+ and HO– and accelerates that of Dyez– with HO–; solubilization of reagents by micelles of cationic, nonionic, and zwitterionic surfactants accelerates the reactions between Dyez+ and HO– and decelerates the reaction of Dyez– with HO–; anionic micelles decelerate both of them. Interest in micellar effects is due to both theoretical application in the study of reaction mechanisms, structure and dynamics of nanosized aggregates in solution, and practical application, for example, in organic synthesis, in industry. Quantitative data processing was carried out according to the Bronsted–Bjerrum and Scatchard equations, as well as linear dependences of solvation energies. The experiment also provides students with practical experience in using the spectrophotometer, as well as graphical and numerical analysis of the data obtained. A new anionic triphenylmethine dye 3,3′-dinitrophenolsulfonephthalein (nitrophenol violet, NPV) was proposed for the study of chemical kinetics. NPV reacts with alkali faster than anionic dyes such as bromophenol blue and phenolphthalein. This property of NPV reduces laboratory practice time.

Cobalt‐Catalysed, Ligand‐Controlled Regiodivergent Alkene Hydrosilylation

AbstractAlkene hydrosilylation is amongst the largest industrial homogenous catalysis processes. Cobalt catalysis offers a sustainable alternative to commonly used platinum catalysts to achieve this transformation. Using two bisiminopyridine cobalt(II) catalysts the regiodivergent hydrosilylation of alkenes has been developed. Variation of pre‐catalyst activator and ligand substituents were investigated to enable the controlled, regiodivergent hydrosilylation of both aryl‐ and alkyl‐substituted alkenes with phenylsilane. In contrast to other regiodivergence strategies, excellent regioselectivity for either isomer was achieved using the same ligand class but differing by a single methyl group (ethyl vs isopropyl).

Deciphering the Superatomic Behavior of Group V Metal Monoxides.

The valence orbitals of Group V metal monoxides exhibit atomic-like properties which mimic that of coinage metal element atoms. The electronic structures of MO-1/0 (M = V, Nb, and Ta) have been determined by negative ion photoelectron velocity map imaging. Electron affinities and vibrational frequencies for the ground state and excited states of MO (M = V, Nb, and Ta) molecules have been identified as well as photoelectron angular distributions. On the basis of the equivalent-electron principle, MO- (M = V, Nb, and Ta) molecules bear valence electron configurations similar to those of coinage metal elemental atoms, despite having more complicated electronic states for molecules, and concomitant mimicry of magnetic superatom. Generally, other than low-spin states of coinage metal atoms, Group V metal monoxides demonstrate a high-spin state except for TaO, possessing the potential applications to inexpensive superatoms in industrial catalysis.

Iron Single Atom Catalyzed Quinoline Synthesis.

The production of high-value chemicals by single-atom catalysis is an attractive proposition for industry owing to its remarkable selectivity. Successful demonstrations to date are mostly based on gas-phase reactions, and reports on liquid-phase catalysis are relatively sparse owing to the insufficient activation of reactants by single-atom catalysts (SACs), as well as, their instability in solution. Here, mechanically strong, hierarchically porous carbon plates are developed for the immobilization of SACs to enhance catalytic activity and stability. The carbon-based SACs exhibit excellent activity and selectivity (≈68%) for the synthesis of substituted quinolines by a three-component oxidative cyclization, affording a wide assortment of quinolines (23 examples) from anilines and acetophenones feedstock in an efficient, atom-economical manner. Particularly, a Cavosonstat derivative can be synthesized through a one-step, Fe1 -catalyzed cyclization instead of traditional Suzuki coupling. The strategy is also applicable to the deuteration of quinolines at the fourth position, which is challenging by conventional methods. The synthetic utility of the carbon-based SAC, together with its reusability and scalability, renders it promising for industrial scale catalysis.

Natural Nanominerals Show Enzyme-Like Activities

Natural nanominerals (NNMs) are progressively deposited during earth’s formation. They have shown a broad range of applications from industrial catalysis, environmental treatment, and earth science to pharmaceutics due to their unique nanostructures and characteristics. Here, we first report that NNMs have intrinsic enzyme-like properties and show good biocompatibility. First, we characterized the morphology and structure of the six most representative NNMs including sepiolite, attapulgite, halloysite, montmorillonite, kaolinite, and diatomite by SEM, TEM, and XRD. Then, we quantitatively tested their peroxidase- (POD-), catalase- (CAT-), oxidase- (OXD-), and superoxide dismutase- (SOD-) like activities. The results indicate that different kinds of NNMs show varying degrees of POD-like, CAT-like, and SOD-like activities and minor OXD-like activity. Finally, we tested their cytotoxicity and found that the selected representative NNMs have no or less influence on cell viability, showing high biosafety. At present, NNMs have been widely used, mostly focusing on the physical and chemical properties, such as luminescence and conductivity. Our work promotes the understanding of NNMs, providing a new direction for the better application of NNMs.

In situ atomic-scale studies of thermal stability and surface reconstruction of ZnO nanowires based Pd nanocatalysts

As innovative nanostructured catalysts, palladium nanoparticles supported on carbon-coated zinc oxide nanowires (PdNPs/C&ZnO-NWs) are widely applied in industrial thermal catalysis, and therefore the real-time insights into their thermal stability and microstructural reconstruction at thermal reaction conditions will greatly extend our knowledge of their physicochemical properties and provide valuable guidance for the applications and designs of future nanocatalysts. The in-situ transmission electron microscopy (TEM) studies revealed the high-temperature resistance to PdNPs aggregations with aids of carbon-coated low-dimensional nanostructures C&ZnO-NWs and elucidated ripening dynamics of PdNPs and the surface reconstruction of C&ZnO-NWs. The operando analysis of PdNPs/C&ZnO-NWs was executed in real-time under working-temperature situations. The aggregations of PdNPs were not observed until reaching a high working temperature of 300 °C and carbon-coated layers could functionally prevent PdNPs from sintering even when ZnO-NWs experienced melting at 500 °C. The time-lapsed TEM investigation proved that the ripening dynamics and time-dependent revolution of PdNPs size are in accordance with the Ostwald ripening process. The subsequent atomic-scale observation revealed the surface reconstruction of ZnO-NWs in the form of ZnO encapsulation over PdNPs and carbon-coated layers during the thermal process, which showed the microscopic evidence of potential deactivation of ZnO-NW-based nanocatalysts in thermal reactions.

Hybrid enzyme catalysts synthesized by a de novo approach for expanding biocatalysis

The two major challenges in industrial enzymatic catalysis are the limited number of chemical reaction types that are catalyzed by enzymes and the instability of enzymes under harsh conditions in industrial catalysis. Expanding enzyme catalysis to a larger substrate scope and greater variety of chemical reactions and tuning the microenvironment surrounding enzyme molecules to achieve high enzyme performance are urgently needed. In this account, we focus on our efforts using the de novo approach to synthesis hybrid enzyme catalysts that can address these two challenges and the structure–function relationship is discussed to reveal the principles of designing hybrid enzyme catalysts. We hope that this account will promote further efforts toward fundamental research and wide applications of designed enzyme hybrid catalysts for expanding biocatalysis.

Highly Selective Hydrogenation of Phenol Catalyzed by Porous BN Supported Ni−Pd Catalysts

AbstractPhenol, as a phenolic organic substance, is widely present in industrial wastewater and is an important organic pollutant. Porous boron nitride (p‐BN) is an ideal material as catalyst support because it has a large specific surface area and a variety of pore structures. In this paper, a series of Ni−Pd/p‐BN catalysts were prepared by precipitation method. Meanwhile, the catalytic performance of the catalysts for the hydrogenation of phenol to cyclohexanol was systematical and comprehensive studied. Significantly, with the optimal catalyst, the conversion of phenol was greatly improved to reach more than 99.9 %, and the selectivity of cyclohexanol could almost exceed 99.8 %. In addition, the Ni−Pd/p‐BN catalyst can be reused as an effective catalyst for numerous cycles, indicating superior reusability and recyclability. After five cycles, the conversion of phenol and the selectivity of cyclohexanol is only reduced to ∼80 %. This catalyst will be a promising material in the field of industrial catalysis applications.

Bubble evolution and manipulation revealed by reconfigurable shape-memory photonic crystals with tunable wettability

Understanding and controlling the behaviors of bubbles on the surface of macroporous materials (SMM) are of vital importance in the development of industrial catalysis, mass transfer, and membrane science. Using shape-memory photonic crystals (SMPCs) with tunable wettability as 3D/2D macroporous supports, we reveal for the first time the bubble evolution on the SMM by structure color. The evolution of oxygen bubbles generated by the film was accompanied by a red/blue shift structural color, which is convenient for analyzing the evolution process. The color contrast is produced by gas–liquid exchange triggered by Laplacian pressure in the macropores, which is regulated by surface wettability. Importantly, the pressure-induced reversible deformation of macropores adjusts surface wettability and promotes the corresponding gas–liquid exchange, enhancing the color contrast. It makes it possible to reveal bubble evolution in liquids with different wettability. Moreover, 2D bowl-shaped SMPCs with bubble anti-adhesion can be constructed by scraping 3D inverse opals. The reversible deformation of bowls can realize the switch between bubble adhesion and anti-adhesion. It improves our understanding of bubble evolution and inspires us to fabricate the next generation of interfacial catalysts, structured electrodes, and mass transfer interfaces.

Design of a thermally stable and highly active SERS optical sensor for the ultrasensitive detection of dye molecules at high-temperature

Surface enhanced Raman spectroscopy (SERS) with both enhanced activity and pronounced thermal stability is very suitable for ultra-sensitive monitoring of thermally assisted chemical bonding/fragmentation reactions in important industrial catalysis. Herein, we report an appealing thermally stable SERS active sensor based on the construction of multiple-branched Au/Ag nanodendrites (NDs). The obtained Au/Ag NDs with tremendous elongated branches and enormous antennas exhibit a much higher SERS activity for dye detection under 785 nm near infrared (NIR) laser irradiation, as compared to as-prepared other reference samples. Meanwhile, the corresponding unique intermetallic synergy can effectively suppress the oxidation of chemically active Ag in a hot environment. It is important that more than 90% SERS activity at room temperature (∼25 ℃) can be well maintained at high temperature (∼170 ℃) within 30 min continuous tests. Thus, it holds great potential for the in-situ SERS monitoring of high-temperature catalytic reactions in the future.

Photoinduced Strong Metal-Support Interaction for Enhanced Catalysis.

Strong metal-support interaction (SMSI) construction is a pivotal strategy to afford thermally robust nanocatalysts in industrial catalysis, but thermally induced reactions (>300 °C) in specific gaseous atmospheres are generally required in traditional procedures. In this work, a photochemistry-driven methodology was demonstrated for SMSI construction under ambient conditions. Encapsulation of Pd nanoparticles with a TiOx overlayer, the presence of Ti3+ species, and suppression of CO adsorption were achieved upon UV irradiation. The key lies in the generation of separated photoinduced reductive electrons (e-) and oxidative holes (h+), which subsequently trigger the formation of Ti3+ species/oxygen vacancies (Ov) and then interfacial Pd-Ov-Ti3+ sites, affording a Pd/TiO2 SMSI with enhanced catalytic hydrogenation efficiency. The as-constructed SMSI layer was reversible, and the photodriven procedure could be extended to Pd/ZnO and Pt/TiO2.

Study of carbon dioxide hydrogenation to hydrocarbons over iron-based Catalysts: Synergistic effect

The full article will be published in the English version of the journal "Catalysis in Industry" No. 4, 2021.Hydrogenation of CO2 to CO and hydrocarbons is carried out over a wide range of catalysts. Group of VIIIB transition metals have proved high conversion and selectively for CO and methane. Meanwhile, low cost and effective catalysts are preferable in an industrial scale. In this work, the synergistic effect of iron content on the catalytic performance were investigated in carbon dioxide hydrogenation reaction. Incipient wetness impregnation procedure was used for the preparation of four γ-Al2O3 supported iron-based catalysts. BET, XRD, H2-TPR and TEM techniques were employed for the catalyst characterization. The evaluation of catalysts were carried out in a fixed bed reactor at the process conditions of temperature of 300 °C, pressure of 20 atm, H2 to CO2 ratio of 3 and GHSV of 3 nl.h–1·gCat–1. It was found that the promoter addition improves the activity of Fe catalyst for both Fischer – Tropsch synthesis (FTS) and Reverse Water Gas Shift (RWGS) reactions. The results showed that conversion of CO2 was from 15.6 to 35.6 % with major products of methane, C2 to C4, C5+ and CO. It was also found that impact of K and Ce promoters into iron catalyst showed the highest conversion and hydrocarbon yield due to the synergistic effect.

Author Correction: Performance metrics for sustainable catalysis in industry

Author Correction: Performance metrics for sustainable catalysis in industry

D3DistalMutation: a Database to Explore the Effect of Distal Mutations on Enzyme Activity.

Enzyme activity is affected by amino acid mutations, particularly mutations near the active site. Increasing evidence has shown that distal mutations more than 10 Å away from the active site may significantly affect enzyme activity. However, it is difficult to study the enzyme regulation mechanism of distal mutations due to the lack of a systematic collection of three-dimensional (3D) structures, highlighting distal mutation site and the corresponding enzyme activity change. Therefore, we constructed a distal mutation database, namely, D3DistalMutation, which relates the distal mutation to enzyme activity. As a result, we observed that approximately 80% of distal mutations could affect enzyme activity and 72.7% of distal mutations would decrease or abolish enzyme activity in D3DistalMutation. Only 6.6% of distal mutations in D3DistalMutation could increase enzyme activity, which have great potential to the industrial field. Among these mutations, the Y to F, S to D, and T to D mutations are most likely to increase enzyme activity, which sheds some light on industrial catalysis. Distal mutations decreasing enzyme activity in the allosteric pocket play an indispensable role in allosteric drug design. In addition, the pockets in the enzyme structures are provided to explore the enzyme regulation mechanism of distal mutations. D3DistalMutation is accessible free of charge at https://www.d3pharma.com/D3DistalMutation/index.php.

Progress and perspective of enzyme immobilization on zeolite crystal materials

Zeolites play irreplaceable roles in the industrial catalysis field due to their diverse pore structures and special physical and chemical properties, which are also one type of the most attractive inorganic materials for the immobilization of enzymes. In this review, the research progress of enzyme immobilization on molecular sieve crystal materials, including the immobilization methods and applications in chemistry, biomedicine, energy and environment areas, are reviewed. Strategies for constructing delaminated zeolites, hierarchical zeolites and hollow-structured zeolites to effectively immobilize enzymes are summarized. Meanwhile, primary perspectives on future zeolite-enzyme composites are proposed.