Catalysis-in-a-Box: Robotic Screening of Catalytic Materials in the Time of COVID-19 and Beyond

Kumar, Gaurav; Bossert, Hannah; McDonald, Dan; Chatzidimitriou, Anargyros; Ardagh, M. Alexander; Pang, Yutong; Lee, Choong Sze; Tsapatsis, Michael; Abdelrahman, Omar A.; Dauenhauer, Paul J.

doi:10.1016/j.matt.2020.06.025

Cited by 17 publications

(23 citation statements)

References 57 publications

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“…4.3 Reaction Activity Measurements. All reactivity measurements were performed at atmospheric pressure using a micro-flow catalytic packed bed reactor contained in a modified gas chromatography (GC) inlet as described in our previous work 57 . A detailed reactor design is shown in Figure S1 and Supplementary Note 2.…”

Section: Materials Characterizationmentioning

confidence: 99%

“…High selectivity may be achieved by lowering the energy barrier to the preferential product by manipulating the energies of reaction intermediates and transition states via catalyst design to modify binding energies of surface species, 1,2 site strength, 3 or steric confinement around the active sites. 4,5 Suppression of side reactions and selectivity improvement can also be achieved utilizing competitive adsorption of inert site-selective titrants on active sites if binding of the titrant is favored over the undesired pathways. 6 In particular, organic bases, such as ammonia, alkyl amines, and pyridine [7][8][9][10] bind on Brønsted acid sites (BAS) even at elevated temperatures above 160 ℃, typical for gas-phase reactions.…”

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confidence: 99%

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On the Spatial Design of Co-Fed Amines for Selective Dehydration of Methyl Lactate to Acrylates

et al. 2021

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Co-feeding an inert and site-selective chemical titrant provides desirable selectivity tuning when titrant adsorption is favored over side reaction pathways on a solid acid catalyst. Here, a selectivity enhancement from 61 to 84 C % was demonstrated for methyl lactate dehydration to methyl acrylate and acrylic acid over a NaY zeolite catalyst using amines as the co-fed titrants to suppress side reactions on in situ-generated Brønsted acid sites (BASs). The effectiveness of BAS titration was evaluated by considering both the basicity and steric properties of the titrant molecule with the goal to maximize the selectivity enhancement. The presence of electron-donating alkyl functional groups not only enhances amine basicity but also introduces additional steric constraints to the molecule with respect to the pore dimensions of the NaY zeolite. While higher basicity of titrant amines favors stronger adsorption on BASs, steric limitations hinder site binding through contributions from internal diffusion limitations and local steric repulsion between the titrant and the zeolite wall around the BAS. Titrant bases with proton affinities above ∼1040 kJ/mol and sizes below 85% of the NaY supercage window or pore diameter are predicted to afford dehydration selectivities above 90 C % to acrylate products.

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Section: Materials Characterizationmentioning

confidence: 99%

mentioning

confidence: 99%

On the Spatial Design of Co-Fed Amines for Selective Dehydration of Methyl Lactate to Acrylates

et al. 2021

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“…The supporting information references additional publications. [17][18][19]34,57,76,[84][85][86][87]…”

Section: Supporting Informationmentioning

confidence: 99%

On the Spatial Design of Co-Fed Amines for Selective Dehydration of Methyl Lactate to Acrylates

Pang¹,

Ardagh²,

Shetty³

et al. 2021

Preprint

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Co-feeding an inert and site-selective chemical titrant provides desirable selectivity tuning when titrant adsorption is favored over side reaction pathways on a solid acid catalyst. Here, a selectivity enhancement from 61 to 84 C % was demonstrated for methyl lactate dehydration to methyl acrylate and acrylic acid over NaY zeolite catalyst using amines as the co-fed titrants to suppress side reactions on in situ generated Brønsted acid sites (BAS). The effectiveness of BAS titration was evaluated by considering both the basicity and steric properties of the titrant molecule with the goal to maximize the selectivity enhancement. The presence of electron-donating alkyl functional groups enhances amine basicity but also introduces additional steric constraints to the molecule with respect to the pore dimensions of the NaY zeolite. While higher basicity of titrant amines favors stronger adsorption on BAS, steric limitations hinder site binding through contributions from internal diffusion limitations and local steric repulsion between titrant and the zeolite wall around the BAS. Titrant bases with proton affinities above ~1040 kJ/mol and sizes below 85% of the NaY supercage window or pore diameter are predicted to afford dehydration selectivities above 90 C % to acrylate products.

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“…The Bayesian optimization algorithm is implemented based on the GPyOpt optimization package. 9 For our applications, we use a GP model with a Matérn 5/2 kernel as a surrogate model, with kernel parameters chosen to optimize the maximum likelihood. We use teacher-student model to compare the performance of Bayesian optimization fused with DFT data (BO_DFT) and standard Bayesian Optimization (BO_baseline).…”

Section: Data Integritymentioning

confidence: 99%

“…[5][6][7] The halide perovskite field and several others require new tools to experimentally navigate these vast spaces efficiently to locate optima and to extract generalisable scientific insights. [8][9][10][11][12][13][14] Machine-learning-based sequential learning approaches (e.g. Bayesian optimisation, BO) have emerged as efficient materials search tools that explore vast variable spaces in a 'closed-loop' fashion, whereby the outcome of one experimental round informs the next without human intervention.…”

Section: Introductionmentioning

confidence: 99%

A Physical Data Fusion Approach to Optimize Compositional Stability of Halide Perovskites

Sun

Tiihonen²,

Oviedo³

et al. 2020

Preprint

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Compositional search within multinary perovskites employing brute force synthesis are prohibitively expensive in large chemical spaces. To identify the most stable multi-cation lead iodide perovskites containing Cs, formamidinium (FA) and methylammonium (MA), we fuse results from density functional theory (DFT) calculations and in situ thin-film degradation test within an end-to-end machine learning (ML) algorithm to inform the compositional optimization of CsxMAyFA1-x-yPbI3. We integrate phase thermodynamics modelling as a probabilistic constraint in a Bayesian optimization (BO) loop, which effectively guides the experimental search while considering both structural and environmental stability. After three optimization rounds and only sampling 1.8% of the compositional space, we identify thin-film compositions centred at Cs0.17MA0.03FA0.80PbI3 that achieve a 3x delay in macroscopic degradation onset under elevated temperature, humidity, and light compared with the more complex state-of-the-art Cs0.05(MA0.17FA0.83)0.95Pb(I0.83Br0.17)3. We find up to 8% of MA can be incorporated into the perovskite structure before stability is significantly compromised. Cs is beneficial at low concentrations, however, beyond 17% is found to contribute to reduced stability. Synchrotron-based grazing-incidence wide-angle X-ray scattering (GIWAXS) further validates that the interplay of chemical decomposition and phase separation governs the non-linear instability landscape of this compositional space. We reveal the detrimental role of the ẟ-CsPbI3 minority phase in accelerating degradation and it can be kinetically suppressed by co-optimising Cs and MA content, providing insights into simplifying perovskite compositions for further environmental stability enhancement. Our approach realizes the effectiveness of ML-enabled data fusion in achieving a holistic, efficient, and physics-informed experimentation for multinary systems, potentially generalisable to materials search in the vast structural and alloyed spaces beyond halide perovskites.

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Catalysis-in-a-Box: Robotic Screening of Catalytic Materials in the Time of COVID-19 and Beyond

Cited by 17 publications

References 57 publications

On the Spatial Design of Co-Fed Amines for Selective Dehydration of Methyl Lactate to Acrylates

On the Spatial Design of Co-Fed Amines for Selective Dehydration of Methyl Lactate to Acrylates

On the Spatial Design of Co-Fed Amines for Selective Dehydration of Methyl Lactate to Acrylates

A Physical Data Fusion Approach to Optimize Compositional Stability of Halide Perovskites

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