Kang Rui Garrick Lim

All Publications

• Nanoscale wetting controls reactive Pd ensembles in synthesis of dilute PdAu alloy catalysts. Nature communications Lim, K. R., Owen, C. J., Kaiser, S. K., Routh, P. K., Mendoza, M., Park, K. K., Kim, T. S., Garg, S., Gardener, J. A., Russotto, L., O'Connor, C. R., Bijl, M., Aizenberg, M., Reece, C., Lee, J. D., Frenkel, A. I., Kozinsky, B., Aizenberg, J. 2025; 16 (1): 6293

  Abstract

  The performance of bimetallic dilute alloy catalysts is largely determined by the size of minority metal ensembles on the nanoparticle surface. By analyzing the synthesis of catalysts comprising Pd8Au92 nanoparticles supported on silica using surface-sensitive techniques, we report that whether Pd overgrowth occurs before or after Au nanoparticle deposition onto the support controls the surface Pd ensemble size and abundance. These differences in Pd ensembles influence catalytic reactivity in H2-D2 isotope exchange and benzaldehyde hydrogenation, which, in correlation with theoretical calculations, is used to elucidate the active site(s) in each reaction. To clarify how the synthetic sequence controls the formation of Pd ensembles, we combine numerical wetting calculations and molecular dynamics simulations (with a machine-learned force field) to visualize Pd deposition and migration on the nanoparticle surface, respectively. Our results suggest that the nanoparticle-support interface restricts nanoparticle accessibility to Pd deposition, which consequently controls the Pd ensemble size, illustrating the critical role of nanoscale wetting phenomena during bimetallic catalyst preparation.

  View details for DOI 10.1038/s41467-025-61540-4

  View details for PubMedID 40628727

  View details for PubMedCentralID 6441046

• Effects of Pd ensemble size in dilute and single atom alloy PdAu catalysts for one-pot selective hydrogenation and reductive amination CATALYSIS SCIENCE & TECHNOLOGY Lim, K., Azizli, T., Kaiser, S. K., Aizenberg, M., Montemore, M. M., Aizenberg, J. 2025

  View details for DOI 10.1039/d5cy00441a

  View details for Web of Science ID 001507325800001

• Active and Stable PtPd Diesel Oxidation Catalysts under Industry-Defined Test Protocols CHEMSUSCHEM Lim, K., Shirman, T., Toops, T. J., Alvarenga, J., Aizenberg, M., Aizenberg, J. 2025: e202500295

  Abstract

  Nanoparticle-supported Pt and Pd catalysts are employed industrially to convert CO and hydrocarbon residue from incomplete diesel fuel combustion into more environmentally-benign products. However, these catalysts deactivate over time due to sintering, especially for Pt nanoparticles which readily generate volatile species under high operating temperatures. Here, we turned the detrimental vapor-mediated sintering of Pt into an advantage by using a physical mixture of Pt and Pd catalysts prepared using a raspberry-colloid-templating (RCT) method. The RCT method produced Pt/Al2O3 and Pd/Al2O3 catalysts with partially embedded NPs to inhibit surface-mediated sintering pathways. As validated using an industry-defined emission control test protocol, aging a physical mixture of Pt/Al2O3 and Pd/Al2O3 at high temperature produced an alloyed PtPd/Al2O3 catalyst that outperformed the fresh catalyst mixture and both individual catalysts for hydrocarbon conversion, while exhibiting high catalytic stability and resistance to sintering and to SO2 poisoning. X-ray photoelectron spectroscopy revealed that in the aged catalyst mixture, half of the Pd content existed in the more active metallic state, compared to the less active oxide forms in the fresh mixture and both individual catalysts, explaining the unusual activity enhancement. Our results represent a practical approach to producing active and stable PtPd/Al2O3 diesel oxidation catalysts for emission control applications.

  View details for DOI 10.1002/cssc.202500295

  View details for Web of Science ID 001445826700001

  View details for PubMedID 40019308

• Partial PdAu nanoparticle embedding into TiO2 support accentuates catalytic contributions from the Au/TiO2 interface PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Lim, K., Kaiser, S. K., Herring, C. J., Kim, T., Perich, M., Garg, S., O'Connor, C. R., Aizenberg, M., van der Hoeven, J. S., Reece, C., Montemore, M. M., Aizenberg, J. 2025; 122 (2): e2422628122

  Abstract

  Despite the broad catalytic relevance of metal-support interfaces, controlling their chemical nature, the interfacial contact perimeter (exposed to reactants), and consequently, their contributions to overall catalytic reactivity, remains challenging, as the nanoparticle and support characteristics are interdependent when catalysts are prepared by impregnation. Here, we decoupled both characteristics by using a raspberry-colloid-templating strategy that yields partially embedded PdAu nanoparticles within well-defined SiO2 or TiO2 supports, thereby increasing the metal-support interfacial contact compared to nonembedded catalysts that we prepared by attaching the same nanoparticles onto support surfaces. Between nonembedded PdAu/SiO2 and PdAu/TiO2, we identified a support effect resulting in a 1.4-fold higher activity of PdAu/TiO2 than PdAu/SiO2 for benzaldehyde hydrogenation. Notably, partial nanoparticle embedding in the TiO2 raspberry-colloid-templated support increased the metal-support interfacial perimeter and consequently, the number of Au/TiO2 interfacial sites by 5.4-fold, which further enhanced the activity of PdAu/TiO2 by an additional 4.1-fold. Theoretical calculations and in situ surface-sensitive desorption analyses reveal facile benzaldehyde binding at the Au/TiO2 interface and at Pd ensembles on the nanoparticle surface, explaining the connection between the number of Au/TiO2 interfacial sites (via the metal-support interfacial perimeter) and catalytic activity. Our results demonstrate partial nanoparticle embedding as a synthetic strategy to produce thermocatalytically stable catalysts and increase the number of catalytically active Au/TiO2 interfacial sites to augment catalytic contributions arising from metal-support interfaces.

  View details for DOI 10.1073/pnas.2422628122

  View details for Web of Science ID 001415241400001

  View details for PubMedID 39786932

  View details for PubMedCentralID PMC11745314

• Restructuring dynamics of surface species in bimetallic nanoparticles probed by modulation excitation spectroscopy NATURE COMMUNICATIONS Routh, P. K., Redekop, E., Prodinger, S., van der Hoeven, J. S., Lim, K., Aizenberg, J., Nachtegaal, M., Clark, A. H., Frenkel, A. I. 2024; 15 (1): 6736

  Abstract

  Restructuring of metal components on bimetallic nanoparticle surfaces in response to the changes in reactive environment is a ubiquitous phenomenon whose potential for the design of tunable catalysts is underexplored. The main challenge is the lack of knowledge of the structure, composition, and evolution of species on the nanoparticle surfaces during reaction. We apply a modulation excitation approach to the X-ray absorption spectroscopy of the 30 atomic % Pd in Au supported nanocatalysts via the gas (H2 and O2) concentration modulation. For interpreting restructuring kinetics, we correlate the phase-sensitive detection with the time-domain analysis aided by a denoising algorithm. Here we show that the surface and near-surface species such as Pd oxides and atomically dispersed Pd restructured periodically, featuring different time delays. We propose a model that Pd oxide formation is preceded by the build-up of Pd regions caused by oxygen-driven segregation of Pd atoms towards the surface. During the H2 pulse, rapid reduction and dissolution of Pd follows an induction period which we attribute to H2 dissociation. Periodic perturbations of nanocatalysts by gases can, therefore, enable variations in the stoichiometry of the surface and near-surface oxides and dynamically tune the degree of oxidation/reduction of metals at/near the catalyst surface.

  View details for DOI 10.1038/s41467-024-51068-4

  View details for Web of Science ID 001286734700036

  View details for PubMedID 39112484

  View details for PubMedCentralID PMC11306641

• Colloidal Templating in Catalyst Design for Thermocatalysis JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Lim, K., Aizenberg, M., Aizenberg, J. 2024; 146 (32): 22103-22121

  Abstract

  Conventional catalyst preparative methods commonly entail the impregnation, precipitation, and/or immobilization of nanoparticles on their supports. While convenient, such methods do not readily afford the ability to control collective ensemble-like nanoparticle properties, such as nanoparticle proximity, placement, and compartmentalization. In this Perspective, we illustrate how incorporating colloidal templating into catalyst design for thermocatalysis confers synthetic advantages to facilitate new catalytic investigations and augment catalytic performance, focusing on three colloid-templated catalyst structures: 3D macroporous structures, hierarchical macro-mesoporous structures, and discrete hollow nanoreactors. We outline how colloidal templating decouples the nanoparticle and support formation steps to devise modular catalyst platforms that can be flexibly tuned at different length scales. Of particular interest is the raspberry colloid templating (RCT) method which confers high thermomechanical stability by partially embedding nanoparticles within its support, while retaining high levels of reactant accessibility. We illustrate how the high modularity of the RCT approach allows one to independently control collective nanoparticle properties, such as nanoparticle proximity and localization, without concomitant changes to other catalytic descriptors that would otherwise confound analyses of their catalytic performance. We next discuss how colloidal templating can be employed to achieve spatially disparate active site functionalization while directing reactant transport within the catalyst structure to enhance selectivity in multistep catalytic cascades. Throughout this Perspective, we highlight developments in advanced characterization that interrogate transport phenomena and/or derive new insights into these catalyst structures. Finally, we offer our outlook on the future roles, applications, and challenges of colloidal templating in catalyst design for thermocatalysis.

  View details for DOI 10.1021/jacs.4c07167

  View details for Web of Science ID 001284769500001

  View details for PubMedID 39101642

  View details for PubMedCentralID PMC11328140

• Controlling nanoparticle placement in Au/TiO₂ inverse opal photocatalysts NANOSCALE Bijl, M., Lim, K., Garg, S., Nicolas, N. J., Visser, N. L., Aizenberg, M., van der Hoeven, J. S., Aizenberg, J. 2024; 16 (29): 13867-13873

  Abstract

  Gold nanoparticle-loaded titania (Au/TiO2) inverse opals are highly ordered three-dimensional photonic structures with enhanced photocatalytic properties. However, fine control over the placement of the Au nanoparticles in the inverse opal structures remains challenging with traditional preparative methods. Here, we present a multi-component co-assembly strategy to prepare high-quality Au/TiO2 inverse opal films in which Au nanoparticles are either located on, or inside the TiO2 matrix, as verified using electron tomography. We report that Au nanoparticles embedded in the TiO2 support exhibit enhanced thermal and mechanical stability compared to non-embedded nanoparticles that are more prone to both leaching and sintering.

  View details for DOI 10.1039/d4nr01200c

  View details for Web of Science ID 001276870700001

  View details for PubMedID 38979601

• Deconvoluting the Individual Effects of Nanoparticle Proximity and Size in Thermocatalysis ACS NANO Lim, K., Kaiser, S. K., Wu, H., Garg, S., O'Connor, C. R., Reece, C., Aizenberg, M., Aizenberg, J. 2024; 18 (24): 15958-15969

  Abstract

  Nanoparticle (NP) size and proximity are two physical descriptors applicable to practically all NP-supported catalysts. However, with conventional catalyst design, independent variation of these descriptors to investigate their individual effects on thermocatalysis remains challenging. Using a raspberry-colloid-templating approach, we synthesized a well-defined catalyst series comprising Pd12Au88 alloy NPs of three distinct sizes and at two different interparticle distances. We show that NP size and interparticle distance independently control activity and selectivity, respectively, in the hydrogenation of benzaldehyde to benzyl alcohol and toluene. Surface-sensitive spectroscopic analysis indicates that the surfaces of smaller NPs expose a greater fraction of reactive Pd dimers, compared to inactive Pd single atoms, thereby increasing intrinsic catalytic activity. Computational simulations reveal how a larger interparticle distance improves catalytic selectivity by diminishing the local benzyl alcohol concentration profile between NPs, thus suppressing its readsorption and consequently, undesired formation of toluene. Accordingly, benzyl alcohol yield is maximized using catalysts with smaller NPs separated by larger interparticle distances, overcoming activity-selectivity trade-offs. This work exemplifies the high suitability of the modular raspberry-colloid-templating method as a model catalyst platform to isolate individual descriptors and establish clear structure-property relationships, thereby bridging the materials gap between surface science and technical catalysts.

  View details for DOI 10.1021/acsnano.4c04193

  View details for Web of Science ID 001242760500001

  View details for PubMedID 38836504

• Nanoparticle proximity controls selectivity in benzaldehyde hydrogenation NATURE CATALYSIS Lim, K., Kaiser, S. K., Wu, H., Garg, S., Perxes Perich, M., van der Hoeven, J. S., Aizenberg, M., Aizenberg, J. 2024; 7 (2): 172-184

  View details for DOI 10.1038/s41929-023-01104-1

  View details for Web of Science ID 001163526400001

• Identifying the Optimal Pd Ensemble Size in Dilute PdAu Alloy Nanomaterials for Benzaldehyde Hydrogenation ACS CATALYSIS Kaiser, S. K., van der Hoeven, J. S., Yan, G., Lim, K., Ngan, H., Garg, S., Karatok, M., Aizenberg, M., Aizenberg, J., Sautet, P., Friend, C. M., Madix, R. J. 2023; 13 (18): 12092-12103

  View details for DOI 10.1021/acscatal.3c02671

  View details for Web of Science ID 001065043200001

• Fluoride-free synthesis and long-term stabilization of MXenes JOURNAL OF MATERIALS RESEARCH Wong, A., Lim, K., Seh, Z. 2022; 37 (22): 3988-3997

  View details for DOI 10.1557/s43578-022-00680-5

  View details for Web of Science ID 000838511100007

• Fundamentals of MXene synthesis NATURE SYNTHESIS Lim, K., Shekhirev, M., Wyatt, B. C., Anasori, B., Gogotsi, Y., Seh, Z. 2022; 1 (8): 601-614

  View details for DOI 10.1038/s44160-022-00104-6

  View details for Web of Science ID 001127081000003

• 2H-MoS₂ on Mo₂CT<i>_x</i> MXene Nanohybrid for Efficient and Durable Electrocatalytic Hydrogen Evolution ACS NANO Lim, K., Handoko, A. D., Johnson, L. R., Meng, X., Lin, M., Subramanian, G., Anasori, B., Gogotsi, Y., Vojvodic, A., Seh, Z. 2020; 14 (11): 16140-16155

  Abstract

  The development of highly efficient and durable earth-abundant hydrogen evolution reaction (HER) catalysts is crucial for the extensive implementation of the hydrogen economy. Members of the 2D MXenes family, particularly Mo2CTx, have recently been identified as promising HER catalysts. However, their inherent oxidative instability in air and aqueous electrolyte solutions is hindering their widespread use. Herein, we present a simple and scalable method to circumvent adventitious oxidation in Mo2CTx MXenes via in situ sulfidation to form a Mo2CTx/2H-MoS2 nanohybrid. The intimate epitaxial coupling at the Mo2CTx/2H-MoS2 nanohybrid interface afforded superior HER activities, requiring only 119 or 182 mV overpotential to yield -10 or -100 mA cm-2geom current densities, respectively. Density functional theory calculations reveal strongest interfacial adhesion was found within the nanohybrid structure as compared to the physisorbed nanohybrid, and the possibility to tune the HER overpotential through manipulating the extent of MXene sulfidation. Critically, the presence of 2H-MoS2 suppresses further oxidation of the MXene layer, enabling the nanohybrid to sustain industrially relevant current densities of over -450 mA cm-2geom with exceptional durability. Less than 30 mV overpotential degradation was observed after 10 continuous days of electrolysis at a fixed -10 mA cm-2geom current density or 100,000 successive cyclic voltammetry cycles. The exceptional HER durability of the Mo2CTx/2H-MoS2 nanohybrid presents a major step forward to realize practical implementation of MXenes as noble metal free catalysts for broad-based applications in water splitting and energy conversion.

  View details for DOI 10.1021/acsnano.0c08671

  View details for Web of Science ID 000595533800155

  View details for PubMedID 33186028

• High Quantum Yield Water-Dispersed Near-Infrared In(Zn)As-In(Zn)P-GaP-ZnS Quantum Dots with Robust Stability for Bioimaging ADVANCED MATERIALS INTERFACES Lim, K., Darwan, D., Wijaya, H., Lim, Z., Shanmugam, J., Wang, T., Lim, L., Ang, W., Tan, Z. 2020; 7 (22)

  View details for DOI 10.1002/admi.202000920

  View details for Web of Science ID 000573617100001

• Rational Design of Two-Dimensional Transition Metal Carbide/Nitride (MXene) Hybrids and Nanocomposites for Catalytic Energy Storage and Conversion ACS NANO Lim, K., Handoko, A. D., Nemani, S., Wyatt, B., Jiang, H., Tang, J., Anasori, B., Seh, Z. 2020; 14 (9): 10834-10864

  Abstract

  Electro-, photo-, and photoelectrocatalysis play a critical role toward the realization of a sustainable energy economy. They facilitate numerous redox reactions in energy storage and conversion systems, enabling the production of chemical feedstock and clean fuels from abundant resources like water, carbon dioxide, and nitrogen. One major obstacle for their large-scale implementation is the scarcity of cost-effective, durable, and efficient catalysts. A family of two-dimensional transition metal carbides, nitrides, and carbonitrides (MXenes) has recently emerged as promising earth-abundant candidates for large-area catalytic energy storage and conversion due to their unique properties of hydrophilicity, high metallic conductivity, and ease of production by solution processing. To take full advantage of these desirable properties, MXenes have been combined with other materials to form MXene hybrids with significantly enhanced catalytic performances beyond the sum of their individual components. MXene hybridization tunes the electronic structure toward optimal binding of redox active species to improve intrinsic activity while increasing the density and accessibility of active sites. This review outlines recent strategies in the design of MXene hybrids for industrially relevant electrocatalytic, photocatalytic, and photoelectrocatalytic applications such as water splitting, metal-air/sulfur batteries, carbon dioxide reduction, and nitrogen reduction. By clarifying the roles of individual material components in the MXene hybrids, we provide design strategies to synergistically couple MXenes with associated materials for highly efficient and durable catalytic applications. We conclude by highlighting key gaps in the current understanding of MXene hybrids to guide future MXene hybrid designs in catalytic energy storage and conversion applications.

  View details for DOI 10.1021/acsnano.0c05482

  View details for Web of Science ID 000615914800001

  View details for PubMedID 32790329

• Atomistic modeling of electrocatalysis: Are we there yet? WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE Abidi, N., Lim, K., Seh, Z., Steinmann, S. N. 2021; 11 (3)

  View details for DOI 10.1002/wcms.1499

  View details for Web of Science ID 000562529100001

• Deep Fluorescence Imaging by Laser-Scanning Excitation and Artificial Neural Network Processing ADVANCED OPTICAL MATERIALS Darwan, D., Lim, K., Wijaya, H., Lim, Z., Wang, T., Ang, W., Tan, Z. 2020; 8 (19)

  View details for DOI 10.1002/adom.202000390

  View details for Web of Science ID 000545780000001

• Efficient Near-Infrared Light-Emitting Diodes based on In(Zn)As-In(Zn)P-GaP-ZnS Quantum Dots ADVANCED FUNCTIONAL MATERIALS Wijaya, H., Darwan, D., Zhao, X., Ong, E., Lim, K., Wang, T., Lim, L., Khoo, K., Tan, Z. 2020; 30 (4)

  View details for DOI 10.1002/adfm.201906483

  View details for Web of Science ID 000495140300001

• Large-Stokes-Shifted Infrared-Emitting InAs-In(Zn)P-ZnSe-ZnS Giant-Shell Quantum Dots by One-Pot Continuous-Injection Synthesis CHEMISTRY OF MATERIALS Wijaya, H., Darwan, D., Lim, K., Wang, T., Khoo, K., Tan, Z. 2019; 31 (6): 2019-2026

  View details for DOI 10.1021/acs.chemmater.8b05023

  View details for Web of Science ID 000462950400021