Shyama Mandal

All Publications

• A physics informed model for the prediction of surface energies and the shape of metal particles. iScience Mandal, S. C., Abild-Pedersen, F. 2026; 29 (1): 114430

  Abstract

  Surface energies of metal-based systems are important for determining the Wulff-constructed shapes of metal nanoparticles and understanding the stability. We have developed a physics informed method to predict the total energy of metal-based systems across a wide range of configurations. Our method has been tested against density functional theory (DFT) calculations for late transition metals. This method enables on-the-fly surface energy predictions based on the fundamental of materials property and allows for the Wulff construction of metal particles for a random number of elemental atoms and without the need for DFT calculations. By making a division between atoms in the different layers of the model system, we can improve the accuracy of the model, suggesting a dissimilarity between the electronic structure due to an alternating compression and expansion of atomic layers. We find that our model accurately and effectively provides valuable insights into the distribution and stability of nanoparticles.

  View details for DOI 10.1016/j.isci.2025.114430

  View details for PubMedID 41536983

  View details for PubMedCentralID PMC12796764

• A physics informed model for the prediction of surface energies and the shape of metal particles ISCIENCE Mandal, S., Abild-Pedersen, F. 2026; 29 (1)

  View details for DOI 10.1016/j.isci.2025.114430

  View details for Web of Science ID 001655246500006

• Toward Instant Prediction of Metal Adatom Diffusion Barriers for Understanding of Sintering and Catalyst Durability JOURNAL OF PHYSICAL CHEMISTRY C Deo, S., Mandal, S., Saini, S., Abild-Pedersen, F. 2025

  View details for DOI 10.1021/acs.jpcc.5c07376

  View details for Web of Science ID 001651833300001

• Crossing the Oxo-Peroxo Wall for Selective Electrochemical Epoxidation. Advanced science (Weinheim, Baden-Wurttemberg, Germany) Basera, P., Mandal, S. C., Abild-Pedersen, F., Bajdich, M. 2025: e17229

  Abstract

  Electrochemical oxidation in water requires the formation of reactive oxygen species to be able to oxidize unsaturated hydrocarbons to epoxides, aldehydes, and ketones. These reactions, broadly classified as alternative oxidation reactions (AOR), directly compete with the prevalent oxygen evolution reaction (OER). In molecular catalysis, the Oxo-Wall dictates a transition from a stable oxo intermediate (OER active) to a meta-stable metal-oxo (OER inactive) generally occurs. In this work on heterogeneous catalysis, the same Oxo-Wall applies, however, a meta-stable oxo preferentially coordinates with lattice oxygen to form a more stable surface peroxo intermediate. A universal free energy onset of this process is identified at 3.39 eV under electrochemical activation in water and show that it is completely decoupled from the OER oxo species. Such decoupling gives rise to a new region of oxygen reactivity relevant for AOR where a selective oxidation of the unsaturated C-C bonds is predicted to occur instead of OER. A distinct AOR overpotential volcano is constructed and identify recently reported electrocatalysts, including palladium-platinum for propylene epoxidation and silver-nickel for ethylene epoxidation, along with others such as TiO2 and CuO. Broader implications and limitations of electrochemical AOR are discussed, highlighting their potential to enable electrochemically enhanced thermal catalysis.

  View details for DOI 10.1002/advs.202517229

  View details for PubMedID 41186102

• Metal-Independent Correlations for Site-Specific Binding Energies of Relevant Catalytic Intermediates. JACS Au Mandal, S. C., Abild-Pedersen, F. 2024; 4 (12): 4790-4798

  Abstract

  Establishing energy correlations among different metals can accelerate the discovery of efficient and cost-effective catalysts for complex reactions. Using a recently introduced coordination-based model, we can predict site-specific metal binding energies (ΔE M) that can be used as a descriptor for chemical reactions. In this study, we have examined a range of metals including Ag, Au, Co, Cu, Ir, Ni, Os, Pd, Pt, Rh, and Ru and found linear correlations between predicted ΔE M and adsorption energies of CH and O (ΔE CH and ΔE O) at various coordination environments for all the considered metals. Interestingly, all the metals correlate with one another under specific surface site coordination, indicating that different metals are interrelated in a particular coordination environment. Furthermore, we have tested and verified for PtPd- and PtIr-based alloys that they follow a similar behavior. Moreover, we have expanded the metal space by taking some early transition metals along with a few s-block metals and shown a cyclic behavior of the adsorbate binding energy (ΔE A) versus ΔE M. Therefore, ΔE CH and ΔE O can be efficiently interpolated between metals, alloys, and intermetallics based on information related to one metal only. This simplifies the process of screening new metal catalyst formulations and their reaction energies.

  View details for DOI 10.1021/jacsau.4c00759

  View details for PubMedID 39735927

  View details for PubMedCentralID PMC11672124

• Metal-Independent Correlations for Site-Specific Binding Energies of Relevant Catalytic Intermediates JACS AU Mandal, S., Abild-Pedersen, F. 2024

  View details for DOI 10.1021/jacsau.4c00759

  View details for Web of Science ID 001370933700001

• Dehydrogenative Coupling for Synthesis of Quinazolin-4(3H)-ones via Tandem Reaction using Ruthenium(II)-Phenyl-Azo-Naphthaldoxime:AnExperimental and Theoretical Investigation. Chemistry, an Asian journal Halder, S., Naskar, S., Jana, D., Kanrar, G., Mandal, S. C., Roy, S., Bharadwaj, N., Pramanik, K., Ganguly, S. 2024: e202401278

  Abstract

  The bidentate N, N, donor phenyl-azo-naphthaldoxime NpLH, 1 was used to synthesize the ruthenium(II) complex trans-[Ru(NpL)(CO)Cl(PPh3)2], 2. It has been characterized by SCXRD, electrochemical and spectral studies. Computational analysis indicates that the low-lying p*-LUMO of the complex has substantial azo-character of coordinated ligand. This property has been exploited to form an efficient electron transfer pre-catalyst to effectuate dehydrogenative functionalization of a large number of benzyl alcohols to quinazolin-4(3H)-ones via condensation with diverse o-amino benzamides as well as N-substituted benzamides under aerobic conditions (57 entries). A reaction mechanism has been projected via isolation of intermediates and certain control experiments. Furthermore, it has been substantiated by theoretical scrutiny using density functional theory (DFT) calculation. The catalytic cycle involves stepwise hydrogen atom transfer (HAT) from benzyl alcohols to the Nazo atoms of the coordinated ligand with subsequent removal of the H-atoms from the Nazo atoms to regenerate the active catalyst.

  View details for DOI 10.1002/asia.202401278

  View details for PubMedID 39610157

• Unveiling the Stability of Encapsulated Pt Catalysts Using Nanocrystals and Atomic Layer Deposition. Journal of the American Chemical Society Liccardo, G., Cendejas, M. C., Mandal, S. C., Stone, M. L., Porter, S., Nhan, B. T., Kumar, A., Smith, J., Plessow, P. N., Cegelski, L., Osio-Norgaard, J., Abild-Pedersen, F., Chi, M., Datye, A. K., Bent, S. F., Cargnello, M. 2024

  Abstract

  Platinum exhibits desirable catalytic properties, but it is scarce and expensive. Optimizing its use in key applications such as emission control catalysis is important to reduce our reliance on such a rare element. Supported Pt nanoparticles (NPs) used in emission control systems deactivate over time because of particle growth in sintering processes. In this work, we shed light on the stability against sintering of Pt NPs supported on and encapsulated in Al2O3 using a combination of nanocrystal catalysts and atomic layer deposition (ALD) techniques. We find that small amounts of alumina overlayers created by ALD on preformed Pt NPs can stabilize supported Pt catalysts, significantly reducing deactivation caused by sintering, as previously observed by others. Combining theoretical and experimental insights, we correlate this behavior to the decreased propensity of oxidized Pt species to undergo Ostwald ripening phenomena because of the physical barrier imposed by the alumina overlayers. Furthermore, we find that highly stable catalysts can present an abundance of under-coordinated Pt sites after restructuring of both Pt particles and alumina overlayers at a high temperature (800 °C) in C3H6 oxidation conditions. The enhanced stability significantly improves the Pt utilization efficiency after accelerated aging treatments, with encapsulated Pt catalysts reaching reaction rates more than two times greater than those of a control supported Pt catalyst.

  View details for DOI 10.1021/jacs.4c06423

  View details for PubMedID 39137357

• Sintering Mechanism of Pt/Al₂O₃ in Complex Emission Gases Elucidated via <i>In Situ</i> Environmental STEM ACS MATERIALS LETTERS Smith, J., Liccardo, G., Cendejas, M. C., Stone, M., Mandal, S., Abild-Pedersen, F., Cargnello, M., Chi, M. 2024

  View details for DOI 10.1021/acsmaterialslett.4c00422

  View details for Web of Science ID 001281960500001

• Machine learning-based screening of Mn-PNP catalysts for the CO₂ reduction reaction using a region-wise ligand-encoded feature matrix ENERGY ADVANCES Das, A., Roy, D., Mandal, S., Pathak, B. 2024

  View details for DOI 10.1039/d3ya00520h

  View details for Web of Science ID 001198780500001

• Unravelling CO2 Reduction Reaction Intermediates on High Entropy Alloy Catalysts: An Interpretable Machine Learning Approach To Establish Scaling Relations. Chemistry (Weinheim an der Bergstrasse, Germany) Roy, D., Charan Mandal, S., Das, A., Pathak, B. 2023: e202302679

  Abstract

  Establishment of a scaling relation among the reaction intermediates is highly important but very much challenging on complex surfaces, such as surfaces of high entropy alloys (HEAs). Herein, we designed an interpretable machine learning (ML) approach to establish a scaling relation among CO2 reduction reaction (CO2 RR) intermediates adsorbed at the same adsorption site. Local Interpretable Model-Agnostic Explanations (LIME), Accumulated Local Effects (ALE), and Permutation Feature Importance (PFI) are used for the global and local interpretation of the utilized black box models. These methods were successfully applied through an iterative way and validated on CuCoNiZnMg and CuCoNiZnSnbased HEAs data. Finally, we successfully predicted adsorption energies of *H2 CO (MAE: 0.24 eV) and *H3 CO (MAE: 0.23 eV) by using the *HCO training data. Similarly, adsorption energy of *O (MAE: 0.32 eV) is also predicted from *H training data. We believe that our proposed method can shift the paradigm of state-of-the-art ML in catalysis towards better interpretability.

  View details for DOI 10.1002/chem.202302679

  View details for PubMedID 37966848

• Classification of Adsorbed Hydrocarbons Based on Bonding Configurations of the Adsorbates and Surface Site Stabilities ACS CATALYSIS Mandal, S., Abild-Pedersen, F. 2023: 13663-13671

  View details for DOI 10.1021/acscatal.3c03239

  View details for Web of Science ID 001082678300001

• Organic additive for the selective C-2-product formation on Cu(100): a density functional theory mechanistic study CATALYSIS SCIENCE & TECHNOLOGY Das, A., Mandal, S., Pathak, B. 2023

  View details for DOI 10.1039/d3cy00857f

  View details for Web of Science ID 001050192200001

• Energy level alignments between organic and inorganic layers in 2D layered perovskites: conjugation vs. substituent. Nanoscale Mahal, E., Mandal, S. C., Roy, D., Pathak, B. 2023

  Abstract

  2D layered hybrid perovskites have attracted huge attention due to their interesting optoelectronic properties and chemical flexibility. Depending upon their electronic structures and properties, these materials can be utilised in various optoelectronic devices like photovoltaics, LEDs and so on. In this context, study of the excited energy levels of the organic spacers can help us to align the excited energy levels of the organic unit with the excitonic level of the inorganic unit according to the requirement of a particular optoelectronic device. We have explored the role of 3-phenyl-2-propenammonium on the electronic structure of a perovskite containing this cation as a spacer. Our results clearly demonstrate the active participation of conjugated ammonium spacers in the electronic structure of a perovskite. Also, we have considered a variety of amines to identify the best alignment with common inorganic units and studied the role of substituents and conjugation on the energy level alignment. Placing the triplet excited level of an organic spacer below the lowest excitonic level of the inorganic unit can induce energy transfer from the inorganic to organic unit, finally resulting in phosphorescence emission. We have shown that the triplet energy level of 3-anthracene-2-propeneamine/3-pyrene-2-propeneamine can be tuned in such a way that there can be an excitonic energy transfer from the Pb2I7/PbI4 inorganic unit-based perovskites. Therefore, perovskite material with such combinations of organic spacer cations will be very useful for light emission applications.

  View details for DOI 10.1039/d3nr01105d

  View details for PubMedID 37067050

• Subsurface Li Monolayer on Cu(111) Surfaces for Upgrading Ethanol to n-Butanol: A Computational Study ACS APPLIED NANO MATERIALS Pathak, B., Tiwari, M., Mandal, S., Das, A. 2023

  View details for DOI 10.1021/acsanm.2c05126

  View details for Web of Science ID 000954009100001

• Ga and Zn Atom-Doped CuAl2O4(111) Surface-Catalyzed CO2 Conversion to Dimethyl Ether: Importance of Acidic Sites JOURNAL OF PHYSICAL CHEMISTRY C Pathak, B., Das, A., Mandal, S., Das, S. 2022; 126 (51): 21628-21637

  View details for DOI 10.1021/acs.jpcc.2c07240

  View details for Web of Science ID 000899456900001

• Antibiotic-triggered reversible luminescence switching in amine-grafted mixed-linker MOF: exceptional turn-on and ultrafast nanomolar detection of sulfadiazine and adenosine monophosphate with molecular keypad lock functionality JOURNAL OF MATERIALS CHEMISTRY A Goswami, R., Mandal, S., Seal, N., Pathak, B., Neogi, S. 2019; 7 (33): 19471-19484

  View details for DOI 10.1039/c9ta06632b

  View details for Web of Science ID 000482139000025

• Guest-Induced Ultrasensitive Detection of Multiple Toxic Organics and Fe<SUP>3+</SUP> Ions in a Strategically Designed and Regenerative Smart Fluorescent Metal-Organic Framework ACS APPLIED MATERIALS & INTERFACES Goswami, R., Mandal, S., Pathak, B., Neogi, S. 2019; 11 (9): 9042-9053

  Abstract

  Luminescent metal-organic frameworks (LMOFs) are promising functional materials for sustainable applications, where an analyte-induced multiresponsive system with good recyclability is beneficial for detecting numerous lethal pollutants. We designed and built the dual-functionalized, three-dimensional Zn(II)-framework [Zn3( bpg)1.5( azdc)3]·(DMF)5.9·(H2O)1.05 (CSMCRI-1) using an -OH group-integrated bpg linker and a -N═N- moiety containing H2 azdc ligand, which functions as a unique tetrasensoric fluorescent probe. The activated CSMCRI-1 (1') represents the hitherto unreported pillar-layer framework for extremely selective fluorescence quenching by nitrofurazone antibiotics as well as explosive nitro-aromatic 2,4,6-trinitrophenol, where ultrasensitive detection is achieved for both the electron-lacking analytes. Impressively, 1' represents the first ever MOF for significant fluorescence "turn-on" detection of toxic and electron-rich 4-aminophenol in the concurrent presence of isomeric analogues. Density functional theory calculations highlight the specific importance of pillar functionalization in the "turn-on" or "turn-off" responses of 1' by electronically divergent toxic organics and provide further proof of supramolecular interactions between the framework and analytes. The fluorescence intensity of 1' dramatically quenches by a trace amount of Fe3+ ions over other competing metal ions, alongside visible colorimetric change of the framework in solid and solution phase upon Fe3+ encapsulation. The sensing ability of 1' remains unaltered for multiple cycles toward all lethal pollutants. The sensing mechanism is attributed to both dynamic and static quenching as well as resonance energy transfer, which strongly comply with the predictions of theoretical simulations. Considering the long-term and real-time monitoring, AND as well as OR molecular logic gates are constructed based on the discriminative fluorescence response for each analyte that provides a platform to fabricate smart LMOFs with multimode logic operations.

  View details for DOI 10.1021/acsami.8b20013

  View details for Web of Science ID 000460996900037

  View details for PubMedID 30717599