Hybrid Catalysis Research Articles

Enhancement of H2-water mass transfer using methyl-modified hollow mesoporous silica nanoparticles for efficient microbial CO2 reduction

Inorganic-microbial hybrid catalysis is an emerging technology that uses electrical energy to drive microorganisms to reduce CO2 into high value-added compounds, and it has broad application prospects in CO2 reduction. However, the low current density (production yield) limits its practical application. Hydrogen-mediated inorganic-microbial hybrid catalysis system can achieve higher current density, but it is limited by low H2 mass transfer. Here, silica nanoparticles were used to enhance the hydrogen mass transfer for highly efficient CO2 reduction. Solid silica (SN), mesoporous silica (MSN), hollow mesoporous silica (HMSN), and methyl-modified hollow mesoporous silica (MHMSN) were firstly prepared and tested for the enhancement of hydrogen mass transfer. Of these, MHMSN nanoparticles at a concentration of 0.3 wt% were the best at enhancing gas-liquid mass transfer, the volumetric mass transfer coefficient (KLa) and saturated dissolved hydrogen concentration of H2 are 0.53 min-1 and 1.81 mg l-1, respectively. Compared with the control group without added nanoparticles, MHMSN significantly increased the solubility and KLa of H2. This can be attributed that the addition of MHMSN promoted the detached process of hydrogen bubbles from the electrode surface, which made the diameter of hydrogen bubbles smaller, increased the gas-liquid mass transfer area, and strengthened the mass transfer process of H2. Furthermore, it was added to the inorganic-microbial hybrid catalysis system to effectively promote the microbial carbon reduction process, achieving a polyhydroxybutyrate (PHB) yield of up to 700 mg l-1, and the electron utilization rate and CO2 conversion rate were 51 % and 58 % higher than the control group, respectively. These results demonstrated that the addition of MHMSN is an effective approach to enhancing the performance of H2-mediated inorganic-microbial hybrid catalysis system.

Cover Feature: Hybrid Catalysis in Concurrent Mode: How to Make Catalysts and Biocatalysts Compatible? (ChemCatChem 14/2024)

Cover Feature: Hybrid Catalysis in Concurrent Mode: How to Make Catalysts and Biocatalysts Compatible? (ChemCatChem 14/2024)

Hybrid Catalysis in Concurrent Mode: How to Make Catalysts and Biocatalysts Compatible?

AbstractFor a long time, catalysis and biocatalysis seemed to be in competition until the organic chemist decided to synergize them for the better. However, their inherent differences presented such a challenge that most of the hybrid catalysis processes developed turned out to be sequential. Nevertheless, some processes have demonstrated that achieving the seemingly impossible was indeed feasible, by combining catalysts and biocatalysts in concurrent mode. This means having them operate under the same experimental conditions, in the presence of all reagents, from the start of the reaction cascade. The objective of this review is to illustrate how it became possible, drawing upon multidisciplinary fields such as organic and inorganic chemistry, chemo‐ and biocatalysis, to reconcile catalysts that are opposed by many parameters. Through a classification of encountered difficulties, organic chemists can swiftly identify methods to overcome them, creating a toolbox to develop new innovative processes.

Electrooxidative Rhodium(III)/Chiral Carboxylic Acid-Catalyzed Enantioselective C-H Annulation of Sulfoximines with Alkynes.

The combination of achiral Cp*Rh(III) with chiral carboxylic acids (CCAs) represents an efficient catalytic system in transition metal-catalyzed enantioselective C-H activation. However, this hybrid catalysis is limited to redox-neutral C-H activation reactions and the adopt to oxidative enantioselective C-H activation remains elusive and pose a significant challenge. Herein, we describe the development of an electrochemical Cp*Rh(III)-catalyzed enantioselective C-H annulation of sulfoximines with alkynes enabled by chiral carboxylic acid (CCA) in an operationally friendly undivided cell at room temperature. A broad range of enantioenriched 1,2-benzothiazines are obtained in high yields with excellent enantioselectivities (up to 99 % yield and 98 : 2 er). The practicality of this method is demonstrated by scale-up reaction in a batch reactor with external circulation. A crucial chiral Cp*Rh(III) intermediate is isolated, characterized, and transformed, providing rational support for a Rh(III)/Rh(I) electrocatalytic cycle.

Electrooxidative Rhodium(III)/Chiral Carboxylic Acid‐Catalyzed Enantioselective C−H Annulation of Sulfoximines with Alkynes

AbstractThe combination of achiral Cp*Rh(III) with chiral carboxylic acids (CCAs) represents an efficient catalytic system in transition metal‐catalyzed enantioselective C−H activation. However, this hybrid catalysis is limited to redox‐neutral C−H activation reactions and the adopt to oxidative enantioselective C−H activation remains elusive and pose a significant challenge. Herein, we describe the development of an electrochemical Cp*Rh(III)‐catalyzed enantioselective C−H annulation of sulfoximines with alkynes enabled by chiral carboxylic acid (CCA) in an operationally friendly undivided cell at room temperature. A broad range of enantioenriched 1,2‐benzothiazines are obtained in high yields with excellent enantioselectivities (up to 99 % yield and 98 : 2 er). The practicality of this method is demonstrated by scale‐up reaction in a batch reactor with external circulation. A crucial chiral Cp*Rh(III) intermediate is isolated, characterized, and transformed, providing rational support for a Rh(III)/Rh(I) electrocatalytic cycle.

Boronic Acid/Palladium Hybrid Catalysis for Regioselective O-Allylation of Carbohydrates.

Novel imidazole-containing boronic acid and palladium hybrid catalysis for regioselective O-allylation of carbohydrates has been developed. This catalytic process enables the introduction of a useful allyl functional group into the equatorial hydroxy group of cis-1,2-diols of various carbohydrates with low catalyst loading and excellent regioselectivities. This is the first report on hybrid catalysis in combination with a Lewis base-containing boronic acid and a transition metal complex.

High conductive polymer PANI link Bi2MoO6 and PBA to establish “tandem hybrid catalysis system” by coupling photocatalysis and PMS activation technology

In order to design an efficient advanced oxidation system to improve the inherent limitations in removing refractory organic pollutants, we couple photocatalysis and peroxymonosulfate (PMS) activation technology to establish a tandem hybrid catalysis system inspired by series hybrid electric vehicles. Among them, Bi2MoO6, as an electric power source, can be driven by fuel (light) to generate continuous power (electron) input into the prussian blue analogues (PBA) through the transmission shaft polyaniline (PANI), allowing it to respond quickly and continuously activate PMS. Therefore, it exhibits excellent catalytic performance to degrade DC increased by 55%, and the catalytic rate constant k increased by 7 times compared with the PMS alone. Continuous flow experiments are explored to reveal the feasibility of engineering applications. This study provides a new strategy of tandem hybrid catalysis system to drive future advanced water treatment technologies.

How Hybrid Catalysis Can Support the Deployment of the “Carbon Cyclic Economy-CCE”

How Hybrid Catalysis Can Support the Deployment of the “Carbon Cyclic Economy-CCE”

Low-Valent Metals in Metal-Organic Frameworks Via Post-Synthetic Modification.

Metal-organic frameworks (MOFs) provide uniquely tunable, periodic platforms for site-isolation of reactive low-valent metal complexes of relevance in modern catalysis, adsorptive applications, and fundamental structural studies. Strategies for integrating such species in MOFs include post-synthetic metalation, encapsulation and direct synthesis using low-valent organometallic complexes as building blocks. These approaches have each proven effective in enhancing catalytic activity, modulating product distributions (i.e., by improving catalytic selectivity), and providing valuable mechanistic insights. In this minireview, we explore these different strategies, as applied to isolate low-valent species within MOFs, with a particular focus on examples that leverage the unique crystallinity, permanent porosity and chemical mutability of MOFs to achieve deep structural insights that lead to new paradigms in the field of hybrid catalysis.

Low‐Valent Metals in Metal‐Organic Frameworks Via Post‐Synthetic Modification

AbstractMetal‐organic frameworks (MOFs) provide uniquely tunable, periodic platforms for site‐isolation of reactive low‐valent metal complexes of relevance in modern catalysis, adsorptive applications, and fundamental structural studies. Strategies for integrating such species in MOFs include post‐synthetic metalation, encapsulation and direct synthesis using low‐valent organometallic complexes as building blocks. These approaches have each proven effective in enhancing catalytic activity, modulating product distributions (i.e., by improving catalytic selectivity), and providing valuable mechanistic insights. In this minireview, we explore these different strategies, as applied to isolate low‐valent species within MOFs, with a particular focus on examples that leverage the unique crystallinity, permanent porosity and chemical mutability of MOFs to achieve deep structural insights that lead to new paradigms in the field of hybrid catalysis.

Ethylbenzene oxidation by a hybrid catalysis system of reconstituted myoglobin and silica-protected PdAu nanoparticles under a hydrogen-oxygen mixed atmosphere

C–H bond oxidation using molecular oxygen as a terminal oxidant is an important reaction in molecular conversions. This reaction is achieved by several enzymes such as cytochrome P450s in biological systems, whereas artificial catalytic systems for this reaction are limited. In this work, the oxidation of ethylbenzene was promoted by a hybrid catalysis system consisting of myoglobin reconstituted with manganese porphycene as an artificial peroxygenase in combination with PdAu nanoparticles encapsulated in hollow mesoporous silica spheres as a solid catalyst to produce hydrogen peroxide, respectively. Neither catalyst alone provides hydroxylated products. Favorable conditions for hydrogen peroxide generation and subsequent C–H bond hydroxylation are different from each other and require optimization of pH and salt concentration. The optimized conditions are found to be 0.5 atm of H2 and 0.5 atm of O2 at pH 8.5 in the presence of 10 mM NaCl. The total optimized turnover number of the hybrid catalysis system for ethyl benzene hydroxylation is 3.6, which is consistent with 97% of the turnover number value of the same reaction catalyzed by reconstituted myoglobin using 0.5 mM hydrogen peroxide under the hydrogen-oxygen mixed atmosphere. This finding indicates that the hybrid catalyst system operates without any negative effects for both catalytic reactions.

Catalytic mechanism of in-situ Ni/C co-incorporation for hydrogen absorption of Mg

Ni and carbon materials exhibit remarkable catalysis for the hydriding reaction of Mg. But the underlying mechanism of Ni/C hybrid catalysis is still unclear. In this work, density functional theory (DFT) calculation is applied to investigate the effect of Ni/C co-incorporation on the hydriding reaction of Mg crystal. The morphology and crystal structure of the Ni/C co-incorporated Mg sample show that the co-incorporated structure is credible. The transition state searching calculation suggests that both the incorporations of Ni and C are beneficial for the H2 dissociation. But Ni atom has a dramatic improvement for H2 dissociation and makes the H diffusion become limiting step of the hyriding reaction. The Ni dz2 orbit and H s orbit accept the electrons and combine together compactly, while the Ni dxy orbit is half-occupied. The catalytic effect of Ni on H2 dissociation can be ascribed to the bridging effect of Ni dxy orbit. The incorporation of C can weaken the over-strong interaction between Ni and H which hindered the H diffusion on Mg(0001). The Ni/C co-incorporated Mg(0001) shows the best performance during hyriding reaction compared with the clean and single incorporated Mg(0001).

Front Cover: Emergence of Non‐photoresponsive Catalytic Techniques for Environmental Remediation and Energy Generation (Chem. Asian J. 9/2023)

In recent years, numerous photocatalysts and electrocatalysts have been developed to address energy and environmental issues, however, some properties such as low efficiency and easy charge recombination limit their applications. Hence, it is imperative to design and explore new catalytic techniques that include non-photoresponsive catalysts. Here, recent advances in exploiting diverse catalytic techniques that can be used in dark environments, including piezocatalysis, thermocatalysis, pyrocatalysis, tribocatalysis and hybrid catalysis (piezocatalysis with pyrocatalysis and tribocatalysis with pyrocatalysis) are summarized. The overall mechanism of each catalytic technique and its applications in different fields such as energy generation, environmental remediation, and carbon dioxide reduction are discussed. More information can be found in the Review by Zong-Hong Lin, Sangmin Lee, Dukhyun Choi et al.

Aldolase and N-heterocyclic carbene gold(i) catalysts: compartmentalization and immobilization on anionic clays for concurrent hybrid catalysis at acidic pH

Limitations to concurrent reactions involving hybrid catalysis, such as acidic pH, elevated temperature and catalyst incompatibilities, were overcome by immobilizing cells harbouring the enzyme, and compartmentalizing catalysts.

Hybrid catalysis for enantioselective Baeyer–Villiger oxidation and stereoselective epoxidation: a Cp*Ir complex to fuel FMN and FAD reduction for flavoprotein monooxygenase modules

Taking advantage of the standalone capacity of the two-component flavoenzyme oxygenation module, we extended the scope of the pH and oxygen robust iridium complex, Cp*Ir(bpy-OMe)H+ to drive enzymatic reactions from a low-cost hydride source.

Linear‐Selective Allylation of Aldehydes with Simple Alkenes Mediated by Quadruple Hybrid Catalysis

AbstractIn this study, we developed a linear‐selective allylation reaction of aldehydes using simple alkenes as starting materials by using a quadruple hybrid catalyst system. The reaction proceeded under mild conditions such as room temperature under visible light irradiation and was applicable to asymmetric reactions. The key for this reaction is the addition of Ni(BF4)2 ⋅ 6H2O catalyst to the previously reported ternary catalyst system, accelerating the allylic transfer process from branch products to thermodynamically stable linear products by increasing the Brønsted acidity of thiophosphoric imide (TPI) catalyst.magnified image

Insight to an efficient and magnetic α-Fe2O3/γ-Fe2O3/Cu2O hybrid catalysis for peroxymonosulfate: preparation, performance, and mechanism

Insight to an efficient and magnetic α-Fe2O3/γ-Fe2O3/Cu2O hybrid catalysis for peroxymonosulfate: preparation, performance, and mechanism

Strengthening the Connection between Science, Society and Environment to Develop Future French and European Bioeconomies: Cutting-Edge Research of VAALBIO Team at UCCS.

The development of the future French and European bioeconomies will involve developing new green chemical processes in which catalytic transformations are key. The VAALBIO team (valorization of alkanes and biomass) of the UCCS laboratory (Unité de Catalyse et Chimie du Solide) are working on various catalytic processes, either developing new catalysts and/or designing the whole catalytic processes. Our research is focused on both the fundamental and applied aspects of the processes. Through this review paper, we demonstrate the main topics developed by our team focusing mostly on oxygen- and hydrogen-related processes as well as on green hydrogen production and hybrid catalysis. The social impacts of the bioeconomy are also discussed applying the concept of the institutional compass.

A Germanium Catalyst Accelerates the Photoredox α-C(sp3)-H Alkylation of Primary Amines.

Site-selective C(sp3)-H functionalizations using photoredox catalysis (PC) and hydrogen atom transfer (HAT) catalysis have received increasing attention. Here, we report a Ph2GeCl2 cocatalyst that greatly improves the yield of α-C(sp3)-H alkylation of primary amines catalyzed by a PC-HAT hybrid system. The α-position of the amino group selectively reacted even when weaker C-H bonds existed in the substrates. This finding may help the design of a novel site-selective hybrid catalysis.

Fabrication of Cu (1 0 0) facet-enhanced ionic liquid/copper hybrid catalysis via one-step electro-codeposition for CO2ER toward C2

Electrochemical reduction of CO2 (CO2ER) to high value-added multicarbon (C2+) is a viable way to promote carbon–neutral cycle. To date, copper (Cu) is reported as the most effective metal catalyst toward C2+, but it remains a challenge to achieve high selectivity and large current density. Incorporating ionic liquid in Cu-based catalysis has been proved an effective strategy, however, most reported methods are either involved too much ionic liquid (IL) as electrolyte or too complex & unstable. Herein, an ionic liquid-embedded Cu electrocatalyst (Cu-IL/GDL) was innovatively constructed through one-step electro-codeposition method, in which a kind of amino-ionic liquid, AFIL, was anchored to the gas diffusion layer (GDL) and embedded by the deposited Cu. Under the excellent synergy between Cu and AFIL, Cu-IL/GDL exhibits higher faradaic efficiency toward ethylene (C2H4, 40.67%) and C2 (C2H4 and C2H5OH, 61.39%) when directing CO2 to carbon-fiber side of electrode in H-cell. To be precise, more Cu (100) facet is stabilized by the capping effect of AFIL, being in favor for C–C coupling; meanwhile more AFIL+ is embedded by the deposited Cu, making for the initiation of CO2ER. Thus, this paper proposes a facial and effective strategy to reinforce Cu (100) facet, and couple and heighten the virtues of ionic liquid and Cu during CO2ER toward C2.