Catalysis Research Research Articles

Standardized Data, Scalable Documentation, Sustainable Storage – EnzymeML As A Basis For FAIR Data Management In Biocatalysis

AbstractThe often reported reproducibility crisis in the biomedical sciences also applies to enzymology and biocatalysis, and mainly results from incomplete reporting of reaction conditions. In this Concept article, an infrastructure based on EnzymeML is sketched, which enables reporting, exchange, and storage of enzymatic data according to the FAIR data principles. EnzymeML is a novel data exchange format for enzymology and biocatalysis, which facilitates the application of the STRENDA Guidelines and thus makes data on enzyme‐catalyzed reactions findable, accessible, interoperable, and reusable. EnzymeML enables the comprehensive documentation of metadata, thus fostering reproducibility and replicability in enzymology and biocatalysis. An EnzymeML Application Programming Interface integrates electronic lab notebooks with modelling platforms and databases on enzymatic reactions, and thus enables the seamless flow of enzymatic data from measurement to modelling to publication, without the need for manual intervention such as reformatting or editing. EnzymeML serves as a valuable tool for the design of biocatalytic experiments and contributes to the vision of a unified research data infrastructure for catalysis research.

Automated Adsorption Workflow for Semiconductor Surfaces and the Application to Zinc Telluride.

Surface adsorption is a crucial step in numerous processes, including heterogeneous catalysis, where the adsorption of key species is often used as a descriptor of efficiency. We present here an automated adsorption workflow for semiconductors which employs density functional theory calculations to generate adsorption data in a high-throughput manner. Starting from a bulk structure, the workflow performs an exhaustive surface search, followed by an adsorption structure construction step, which generates a minimal energy landscape to determine the optimal adsorbate-surface distance. An extensive set of energy-based, charge-based, geometric, and electronic descriptors tailored toward catalysis research are computed and saved to a personal user database. The application of the workflow to zinc telluride, a promising CO2 reduction photocatalyst, is presented as a case study to illustrate the capabilities of this method and its potential as a material discovery tool.

Recent Progress in (Photo-)-Electrochemical Conversion of CO2 With Metal Porphyrinoid-Systems.

Since decades, the global community has been facing an environmental crisis, resulting in the need to switch from outdated to new, more efficient energy sources and a more effective way of tackling the rising carbon dioxide emissions. The activation of small molecules such as O2, H+, and CO2 in a cost—and energy-efficient way has become one of the key topics of catalysis research. The main issue concerning the activation of these molecules is the kinetic barrier that has to be overcome in order for the catalyzed reaction to take place. Nature has already provided many pathways in which small molecules are being activated and changed into compounds with higher energy levels. One of the most famous examples would be photosynthesis in which CO2 is transformed into glucose and O2 through sunlight, thus turning solar energy into chemical energy. For these transformations nature mostly uses enzymes that function as catalysts among which porphyrin and porphyrin-like structures can be found. Therefore, the research focus lies on the design of novel porphyrinoid systems (e.g. corroles, porphyrins and phthalocyanines) whose metal complexes can be used for the direct electrocatalytic reduction of CO2 to valuable chemicals like carbon monoxide, formate, methanol, ethanol, methane, ethylene, or acetate. For example the cobalt(III)triphenylphosphine corrole complex has been used as a catalyst for the electroreduction of CO2 to ethanol and methanol. The overall goal and emphasis of this research area is to develop a method for industrial use, raising the question of whether and how to incorporate the catalyst onto supportive materials. Graphene oxide, multi-walled carbon nanotubes, carbon black, and activated carbon, to name a few examples, have become researched options. These materials also have a beneficial effect on the catalysis through for instance preventing rival reactions such as the Hydrogen Evolution Reaction (HER) during CO2 reduction. It is very apparent that the topic of small molecule activation offers many solutions for our current energy as well as environmental crises and is becoming a thoroughly investigated research objective. This review article aims to give an overview over recently gained knowledge and should provide a glimpse into upcoming challenges relating to this subject matter.

Front Cover: A Unified Research Data Infrastructure for Catalysis Research – Challenges and Concepts (ChemCatChem 14/2021)

Front Cover: A Unified Research Data Infrastructure for Catalysis Research – Challenges and Concepts (ChemCatChem 14/2021)

Ionic Liquid-Stabilized Single-Atom Rh Catalyst Against Leaching

Ionic Liquid-Stabilized Single-Atom Rh Catalyst Against Leaching

Analysis of Updated Literature Data up to 2019 on the Oxidative Coupling of Methane Using an Extrapolative Machine‐Learning Method to Identify Novel Catalysts

AbstractWe have constructed and analyzed an updated dataset consisting of 4759 experimental datapoints for the oxidative coupling of methane (OCM) reaction based on literature data reported before 2020 (∼2019) using machine learning (ML) methods. Several ML methods, including random forest regression (RFR), extra trees regression (ETR), and gradient boosting regression with XGBoost (XGB), were used in conjunction with our proposed approach, in which elemental features are used as input representations rather than inputting the catalyst compositions directly. A recent research trend, namely, the extensive exploration of Mn/Na2WO4/SiO2 catalyst systems in recent years due to their high activity and durability, was clearly reflected in the dataset analysis. An ML model for the prediction of the reaction outcome (C2 yield) was successfully developed, and feature importance scores and SHapley Additive exPlanations (SHAP) values were calculated based on ETR and XGB, respectively, to identify the input variables with the greatest influence on the catalyst performance and observe how these important variables affect the C2 yield in the OCM. The discovery and optimization of catalytic processes using ML as a “surrogate” model were explored, and promising catalytic system candidates for the OCM reaction were identified. Notably, the developed ML model predicted catalysts containing elements that do not appear in the OCM dataset. This clearly demonstrates desirably high potential of our ML model to enable extrapolative predictions for ML‐aided future catalysis research.

Activity of Pdn (n = 1–5) Clusters on Alumina Film on Ni3Al(111) for CO Oxidation: A Molecular Beam Study

Single atom catalyst (SAC) is a vivid new area of research in catalysis. However, the activity in CO oxidation of isolated Pt or Pd atoms, generally supported on an oxide powder, is still controversial. Furthermore, the steady state activity of few atoms clusters is still not yet quantitatively known. In this work we study, by molecular beam reactive scattering (MBRS), the activity of Pd$_{\rm n}$ ($n$ = 1-5) clusters, grown on a nanostructured alumina films on a Ni$_3$Al(111) surface. It is shown that the single atoms are not active at 473 K but they diffuse and coalesce at 533K forming larger clusters. The activity of a cluster is proportional to the number of atoms it contains (n=2-5). At 533 K, the activity per (surface-) atom, which is the turnover frequency (TOF), is constant. Its value is close to those obtained for large clusters of 181$\pm$13 atoms and Pd (111) extended surfaces, in the same experimental conditions.

Future directions of catalytic chemistry

Abstract The philosophy of sustainable development is prevailing worldwide, and will probably bring about a society revolution trend in the future. Catalytic chemistry will play a crucial role in sustainable economic development since at least a catalytic process is involved in almost all-important areas of chemical industry, such as synthesis of chemicals and materials, energy production and conversion as well as pollution abatement and environmental protection. In this paper, we attempt to summarize three common critical directions for catalysis research, in order to meet future needs for sustainable economic development. (i) The discovery of high-performance catalysts will evolve from trial-and-error to rational design. This is due to the maturing theory-experiment joint research schemes and the increasing abilities to explore dynamic nature of catalysts under reaction conditions. (ii) The catalysis for the transition of energy and chemicals generation from oil and coal to more renewable sources will be highly pursued. (iii) The catalysis for cleaner chemical processes will be another active research direction. In Sections “Sustainable catalysis for renewable fuels and chemicals” and “Ecologically clean catalytic process”, some important examples are discussed especially.

A High-Performance Continuous Flow MEA Reactor for Electroreduction CO2 to Formate

The electrochemical reduction of carbon dioxide reduction reaction (CO2RR) to liquid fuels and industrial chemicals represents a promising approach to the environmental remediation of carbon emissions and utilizing intermittent renewable electricity. However, the traditional device of electrolysis CO2 is seriously limited by low CO2 solubility, large PH gradient and high ohmic resistance due to the large distance between two electrodes, which is not applicable to industrial production. Herein, we demonstrate a high-performance continuous flow membranes electrode assembly (MEA) reactor based a self-growing Cu-Sn bimetallic electrocatalysts in the liquid-phase to electroreduction of CO2 to formate. We then via testing different electrolyzer structure explore the best performance of the flow MEA reactor, and compare with H-type cell. Notably, the reactor is designed not only greatly increase current density (66.41 mA cm-2) at -1.11 VRHE, but also maintain high Faraday efficiency (89.56%), and that can effective separation of the gaseous/liquid production. And then, we achieve the production rate of 1 L CO2 to formate (163 μmol h -1 cm-2) at working electrode at -0.97 VRHE and cell voltage at 3.17 V after 20 hours electrolysis. This present study provides a novel reactor can maximize the use of catalyst activity for electrochemical CO2RR and other emerging electrochemical catalysis research.

Reductive Formylation of Nitroarenes using HCOOH over Bimetallic C−N Framework Derived from the Integration of MOF and COF

AbstractCoZn embedded C−N framework is prepared by the carbonization of CoZn containing MOF integrated with COF porous architecture in Ar atmosphere. The graphitic nature of porous carbon is confirmed from Raman analysis. The porosity and nanostructure information are retrieved from N2‐sorption and transmission electron microscopic analysis, respectively. The incorporation of different metals and their oxidation states and types of nitrogen present in the C−N framework are confirmed from X‐ray photoelectron spectroscopy. The basicity of the materials is determined from a CO2‐temperature programmed desorption. ZnCo embedded C−N framework exhibits excellent activity in the selective reductive formylation using HCOOH. For comparison, more than 15 materials are prepared, and their activities are compared. Several control experiments are performed to establish a structure‐activity relation. The recycling experiment, hot‐filtration test, and poisoning experiment demonstrate the metal embedded porous C−N framework‘s recyclability and stability. A reaction mechanism for the reductive N‐formylation of nitroaromatics is presented based on structure‐activity relationship, control reactions, and physicochemical characterizations. The development of interesting MOF‐COF‐derived metal nanoclusters embedded C−N framework for selective reductive formylation of nitroaromatics using formic acid will be highly attractive to catalysis researchers and industrialists.

Resolving multifrequential oscillations and nanoscale interfacet communication in single-particle catalysis.

In heterogeneous catalysis research, the reactivity of individual nanofacets of single particles is typically not resolved. We applied in situ field electron microscopy to the apex of a curved rhodium crystal (radius of 650 nanometers), providing high spatial (~2 nanometers) and time resolution (~2 milliseconds) of oscillatory catalytic hydrogen oxidation, to image adsorbed species and reaction fronts on the individual facets. Using ionized water as the imaging species, the active sites were directly imaged with field ion microscopy. The catalytic behavior of differently structured nanofacets and the extent of coupling between them were monitored individually. We observed limited interfacet coupling, entrainment, frequency locking, and reconstruction-induced collapse of spatial coupling. The experimental results are backed up by microkinetic modeling of time-dependent oxygen species coverages and oscillation frequencies.

In Memoriam Prof. Dr.‐Ing. Jens Weitkamp

AbstractNo abstract.

Surface composition of AgPd single-atom alloy catalyst in an oxidative environment.

Single-atom alloys (SAAs) have recently gained considerable attention in the field of heterogeneous catalysis research due to their potential for novel catalytic properties. While SAAs are often examined in reactions of reductive atmospheres, such as hydrogenation reactions, in the present work, we change the focus to AgPd SAAs in oxidative environments since Pd has the highest catalytic activity of all metals for oxidative reactions. Here, we examine how the chemical reactivity of AgPd SAAs differs from its constituent Pd in an oxidative atmosphere. For this purpose, electronic structure changes in an Ag0.98Pd0.02 SAA foil in 1 mbar of O2 were studied by in situ x-ray photoemission spectroscopy and compared with the electronic structure of a Pd foil under the same conditions. When heated in an oxidative atmosphere, Pd in Ag0.98Pd0.02 partly oxidizes and forms a metastable PdOx surface oxide. By using a peak area modeling procedure, we conclude that PdOx on Ag0.98Pd0.02 is present as thin, possibly monolayer thick, PdOx islands on the surface. In comparison to the PdO formed on the Pd foil, the PdOx formed on AgPd is substantially less thermodynamically stable, decomposing at temperatures about 270 °C lower than the native oxide on Pd. Such behavior is an interesting property of oxides formed on dilute alloys, which could be potentially utilized in catalytic oxidative reactions such as methane oxidation.

Strategies for combining triplet–triplet annihilation upconversion sensitizers and acceptors in a host matrix

• The review highlights the evolving trends in TTA-UC with comprehensive citations. • Insights on host matrix framework impregnated TTA-UC donor acceptor pairs. • Categorize sensitizer-emitter pairs systematically and summarize key metrics. • Briefly emphasize shortcomings and prospects and selected applications. Triplet-triplet annihilation upconversion (TTA-UC) has been transformed by innovative state-of-the-art developments concerning host matrix framework and nano/micro-substrates that encapsulate the new and existing chromophore pairs. The current review identifies and oversees a timely coverage of such evolving layout trends to further extend the scope of TTA-UC to abundant opportunities for research through excited-state engineering. The article reviews the latest advances in; i) pattern and layouts of the substrates (silica, polymer, inorganic nanocrystals, metal–organic frameworks, micelles, and liposomes), media (gel), and phenomenon (surface plasmon resonance) that drives the process; ii) a comparison of the fundamental features and applications of the smart design patterns; iii) a brief section contributed to the potential triplet sensitizers, annihilators its database and iv) selected applications with a prospect of implementation. The dissemination of this review will be applicable in the form of strategies and research in renewable energy, photo-redox catalysis, biological and material sciences.

Tools and Methods for Investigating Synthetic Metal-Catalyzed Reactions in Living Cells.

Although abiotic catalysts are capable of promoting numerous new-to-nature reactions, only a small subset has so far been successfully integrated into living systems. Research in intracellular catalysis requires an interdisciplinary approach that takes advantage of both chemical and biological tools as well as state-of-the-art instrumentations. In this perspective, we will focus on the techniques that have made studying metal-catalyzed reactions in cells possible using representative examples from the literature. Although the lack of quantitative data in vitro and in vivo has somewhat limited progress in the catalyst development process, recent advances in characterization methods should help overcome some of these deficiencies. Given its tremendous potential, we believe that intracellular catalysis will play a more prominent role in the development of future biotechnologies and therapeutics.

Dynamic Interconversion of Metal Active Site Ensembles in Zeolite Catalysis.

Catalysis science is founded on understanding the structure, number, and reactivity of active sites. Kinetic models that consider active sites to be static and noninteracting entities are routinely successful in describing the behavior of heterogeneous catalysts. Yet, active site ensembles often restructure in response to their external environment and even during steady-state catalytic turnover, sometimes requiring non-mean-field kinetic treatments to describe distance-dependent interactions among sites. Such behavior is being recognized more frequently in modern catalysis research, with the advent of experimental methods to quantify turnover rates with increasing precision, an expanding arsenal of operando characterization tools, and computational descriptions of atomic structure and motion at chemical potentials and timescales increasingly relevant to reaction conditions. This review focuses on dynamic changes to metal active site ensembles on zeolite supports, which are silica-based crystalline materials substituted with Al that generate binding sites for isolated and low-nuclearity metal site ensembles. Metal sites can become solvated and mobilized during reaction, facilitating interactions among sites that change their nuclearity and function. Such intersite communication can be regulated by the zeolite support, resulting in non-single-site and potentially non-mean-field kinetic behavior arising from mechanisms of catalytic action that combine elements of those canonically associated with homogeneous and heterogeneous catalysis.We discuss recent literature examples that document dynamic active site behavior in metal-zeolites and outline methodologies to identify and interpret such behavior. We conclude with our outlook on future research directions to develop this evolving branch of catalysis science and harness it for practical applications.

A Unified Research Data Infrastructure for Catalysis Research – Challenges and Concepts

AbstractModern research methods produce large amounts of scientifically valuable data. Tools to process and analyze such data have advanced rapidly. Yet, access to large amounts of high‐quality data remains limited in many fields, including catalysis research. Implementing the concept of FAIR data (Findable, Accessible, Interoperable, Reusable) in the catalysis community would improve this situation dramatically. The German NFDI initiative (National Research Data Infrastructure) aims to create a unique research data infrastructure covering all scientific disciplines. One of the consortia, NFDI4Cat, proposes a concept that serves all aspects and fields of catalysis research. We present a perspective on the challenging path ahead. Starting out from the current state, research needs are identified. A vision for a integrating all research data along the catalysis value chain, from molecule to chemical process, is developed. Respective core development topics are discussed, including ontologies, metadata, required infrastructure, IP, and the embedding into research community. This Concept paper aims to inspire not only researchers in the catalysis field, but to spark similar efforts also in other disciplines and on an international level.

Single-atom alloy catalysts designed by first-principles calculations and artificial intelligence

Single-atom-alloy catalysts (SAACs) have recently become a frontier in catalysis research. Simultaneous optimization of reactants’ facile dissociation and a balanced strength of intermediates’ binding make them highly efficient catalysts for several industrially important reactions. However, discovery of new SAACs is hindered by lack of fast yet reliable prediction of catalytic properties of the large number of candidates. We address this problem by applying a compressed-sensing data-analytics approach parameterized with density-functional inputs. Besides consistently predicting efficiency of the experimentally studied SAACs, we identify more than 200 yet unreported promising candidates. Some of these candidates are more stable and efficient than the reported ones. We have also introduced a novel approach to a qualitative analysis of complex symbolic regression models based on the data-mining method subgroup discovery. Our study demonstrates the importance of data analytics for avoiding bias in catalysis design, and provides a recipe for finding best SAACs for various applications.

Clariant signs catalysis research partnership with prestigious ETH Zurich University

Clariant signs catalysis research partnership with prestigious ETH Zurich University

Oxidation-induced structural transition of two-dimensional iron oxide on Au(111)

Understanding the dynamic changes of catalytically active nanostructures (NSs) under reaction conditions is a pivotal challenge in catalysis research, which has been intensively studied on metal catalysts, but less on oxide NSs. Here, we synthesized two-dimensional (2D) FeO NSs and thin films on Au(111) and studied their oxidation process in O2 from ultrahigh vacuum to near-ambient-pressure (NAP) conditions, using the combination of in-situ NAP scanning tunneling microscopy and x-ray photoelectron spectroscopy. Our studies revealed atomic details on the transition process from the FeO bilayer to the FeO2 tri-layer on Au(111). Further, we found FeO2 NSs and thin layers are metastable on Au(111) and would undergo a three-dimensional phase change upon further thermal treatments. Our study has thus provided insight on the structural dynamics of 2D iron oxide under reaction conditions and enabled further understanding on the design of the oxide-metal interface.