Metal-mediated chemical reactions have been a vital area of research for over a century. Recently, there has been increasing effort to improve the performance of metal-mediated catalysis by optimizing the structure and chemical environment of active catalytic species towards process intensification and sustainability. Network-supported catalysts use a solid (rigid or flexible) support with embedded metal catalysts, ideally allowing for efficient precursor access to the catalytic sites and simultaneously not requiring a catalyst separation step following the reaction with minimal catalyst leaching. This minireview focuses on recent developments of network-supported catalysts to improve the performance of a wide range of metal-mediated catalytic reactions. We discuss in detail the different strategies to realize the combined benefits of homogeneous and heterogeneous catalysis in a metal catalyst support. We outline the unique versatility, tunability, properties, and activity of such hybrid catalysts in batch and continuous flow configurations. Furthermore, we present potential future directions to address some of the challenges and shortcomings of current flexible network-supported catalysts.
more »
« less
Neural network embeddings based similarity search method for atomistic systems
With the popularity of machine learning growing in the field of catalysis there are increasing numbers of catalyst databases becoming available. These databases provide us with the opportunity to search for catalysts with desired properties, which could lead to the discovery of new catalysts. However, while there are search methods for molecules based on similarity metrics, for solid-state catalyst systems there is not yet a straightforward search method. In this work, we propose a neural network embeddings based similarity search method that is applicable for both molecules and solid-state catalyst systems. We illustrate how the search method works and show search examples for the QM9, Materials Project (MP) and Open Catalyst 2020 (OC20) databases. We show that the configurations found present similarity in terms of geometry, composition, energy and in the electronic density of states. These results imply the neural network embeddings have encoded effective information that could be used to retrieve molecules and materials with similar properties.
more »
« less
- Award ID(s):
- 1921946
- PAR ID:
- 10558686
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Digital Discovery
- Volume:
- 1
- Issue:
- 5
- ISSN:
- 2635-098X
- Page Range / eLocation ID:
- 636 to 644
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
High-efficiency and low-cost catalysts for the oxygen evolution reaction (OER) in acidic electrolytes are critical for electrochemical water splitting in proton exchange membrane (PEM) electrolyzers to produce green hydrogen, a clean fuel for sustainable energy conversion and storage. Among OER catalysts, solid-state synthesized SrCo1−xIrxO3 has demonstrated superior activity compared to commercial standards, such as IrO2 and RuO2. However, the solid-state synthesis process is economically inefficient for industrial use due to the potential for impurities and low yield of the final product. In addition, the requirement for electrochemical cycling to activate the catalyst introduces contaminations and uncertainties for industrial applications. In this study, a modified solution-based sol–gel method was employed to produce SrCo0.5Ir0.5O3 (SCIO) with high purity and yield. Subsequent ball milling and acid leaching treatments were applied, resulting in a catalyst with higher efficiency than those activated solely by electrochemical cycling. The electrochemical analysis and physical characterizations of our SCIO catalyst after ex-situ post-synthesis treatments show a similar active phase in composition and structure to those obtained through in situ electrochemical cycling and activation. Our approach simplifies the preparation process, making the catalyst ready for direct use in PEM electrolyzers without further treatment, offering a promising solution for producing high-performance, industrial-scale OER catalysts.more » « less
-
Properties in material composition and crystal structures have been explored by density functional theory (DFT) calculations, using databases such as the Open Quantum Materials Database (OQMD). Databases like these have been used currently for the training of advanced machine learning and deep neural network models, the latter providing higher performance when predicting properties of materials. However, current alternatives have shown a deterioration in accuracy when increasing the number of layers in their architecture (over-fitting problem). As an alternative method to address this problem, we have implemented residual neural network architectures based on Merge and Run Networks, IRNet and UNet to improve performance while relaxing the observed network depth limitation. The evaluation of the proposed architectures include a 9:1 ratio to train and test as well as 10 fold cross validation. In the experiments we found that our proposed architectures based on IRNet and UNet are able to obtain a lower Mean Absolute Error (MAE) than current strategies. The full implementation (Python, Tensorflow and Keras) and the trained networks will be available online for community validation and advancing the state of the art from our findings.more » « less
-
Abstract Optical properties in solids, such as refractive index and absorption, hold vast applications ranging from solar panels to sensors, photodetectors, and transparent displays. However, first‐principles computation of optical properties from crystal structures is a complex task due to the high convergence criteria and computational cost. Recent progress in machine learning shows promise in predicting material properties, yet predicting optical properties from crystal structures remains challenging due to the lack of efficient atomic embeddings. Here, Graph Neural Network for Optical spectra prediction (GNNOpt) is introduced, an equivariant graph‐neural‐network architecture featuring universal embedding with automatic optimization. This enables high‐quality optical predictions with a dataset of only 944 materials. GNNOpt predicts all optical properties based on the Kramers‐Krönig relations, including absorption coefficient, complex dielectric function, complex refractive index, and reflectance. The trained model is applied to screen photovoltaic materials based on spectroscopic limited maximum efficiency and search for quantum materials based on quantum weight. First‐principles calculations validate the efficacy of the GNNOpt model, demonstrating excellent agreement in predicting the optical spectra of unseen materials. The discovery of new quantum materials with high predicted quantum weight, such as SiOs, which host exotic quasiparticles with multifold nontrivial topology, demonstrates the potential of GNNOpt in predicting optical properties across a broad range of materials and applications.more » « less
-
Abstract As a subfield of artificial intelligence (AI), machine learning (ML) has emerged as a versatile tool in accelerating catalytic materials discovery because of its ability to find complex patterns in high‐dimensional data. While the intricacy of cutting‐edge ML models, such as deep learning, makes them powerful, it also renders decision‐making processes challenging to explain. Recent advances in explainable AI technologies, which aim to make the inner workings of ML models understandable to humans, have considerably increased our capacity to gain insights from data. In this study, taking the oxygen reduction reaction (ORR) on {111}‐oriented Pt monolayer core–shell catalysts as an example, we show how the recently developed theory‐infused neural network (TinNet) algorithm enables a rapid search for optimal site motifs with the chemisorption energy of hydroxyl (OH) as a single descriptor, revealing the underlying physical factors that govern the variations in site reactivity. By exploring a broad design space of Pt monolayer core–shell alloys ( candidates) that were generated from thermodynamically stable bulk structures in existing material databases, we identified novel alloy systems along with previously known catalysts in the goldilocks zone of reactivity properties. SHAP (SHapley Additive exPlanations) analysis reveals the important role of adsorbate resonance energies that originate from ‐band interactions in chemical bonding at metal surfaces. Extracting physical insights into surface reactivity with explainable AI opens up new design pathways for optimizing catalytic performance beyond active sites.more » « less
An official website of the United States government

