Rong Ye | University of Michigan (original) (raw)

Papers by Rong Ye

Nature Chemistry, 2023

Microscopic sequences of synthetic polymers play crucial roles in the polymer properties, but are... more Microscopic sequences of synthetic polymers play crucial roles in the polymer properties, but are generally unknown and inaccessible to traditional measurements. Here we report real-time optical sequencing of single synthetic copolymer chains under living polymerization conditions. We achieve this by carrying out multi-colour imaging of polymer growth by single catalysts at single-monomer resolution using CREATS (coupled reaction approach toward super-resolution imaging). CREATS makes a reaction effectively fluorogenic, enabling single-molecule localization microscopy of chemical reactions at higher reactant concentrations. Our data demonstrate that the chain propagation kinetics of surface-grafted polymerization contains temporal fluctuations with a defined memory time (which can be attributed to neighbouring monomer interactions) and chain-length dependence (due to surface electrostatic effects). Furthermore, the microscopic sequences of individual copolymers reveal their tendency to form block copolymers, and, more importantly, quantify the size distribution of individual blocks for comparison with theoretically random copolymers. Such sequencing capability paves the way for single-chain-level structure–function correlation studies of synthetic polymers.

Nature Communications, 2021

Adsorption plays vital roles in many processes including catalysis, sensing, and nanomaterials de... more Adsorption plays vital roles in many processes including catalysis, sensing, and nanomaterials design. However, quantifying molecular adsorption, especially at the nanoscale, is challenging, hindering the exploration of its utilization on nanomaterials that possess heterogeneity across different length scales. Here we map the adsorption of nonfluorescent small molecule/ion and polymer ligands on gold nanoparticles of various morphologies in situ under ambient solution conditions, in which these ligands are critical for the particles' physiochemical properties. We differentiate at nanometer resolution their adsorption affinities among different sites on the same nanoparticle and uncover positive/negative adsorption cooperativity, both essential for understanding adsorbate-surface interactions. Considering the surface density of adsorbed ligands, we further discover crossover behaviors of ligand adsorption between different particle facets, leading to a strategy and its implementation in facet-controlled synthesis of colloidal metal nanoparticles by merely tuning the concentration of a single ligand.

Science advances, 2017

Solar-driven photocatalytic conversion of CO2 into fuels has attracted a lot of interest; however... more Solar-driven photocatalytic conversion of CO2 into fuels has attracted a lot of interest; however, developing active catalysts that can selectively convert CO2 to fuels with desirable reaction products remains a grand challenge. For instance, complete suppression of the competing H2 evolution during photocatalytic CO2-to-CO conversion has not been achieved before. We design and synthesize a spongy nickel-organic heterogeneous photocatalyst via a photochemical route. The catalyst has a crystalline network architecture with a high concentration of defects. It is highly active in converting CO2 to CO, with a production rate of ~1.6 × 10(4) μmol hour(-1) g(-1). No measurable H2 is generated during the reaction, leading to nearly 100% selective CO production over H2 evolution. When the spongy Ni-organic catalyst is enriched with Rh or Ag nanocrystals, the controlled photocatalytic CO2 reduction reactions generate formic acid and acetic acid. Achieving such a spongy nickel-organic photoca...

Angewandte Chemie International Edition, 2016

Controlled synthesis of transition-metal hydroxides and oxides with earth-abundant elements have ... more Controlled synthesis of transition-metal hydroxides and oxides with earth-abundant elements have attracted significant interest because of their wide applications,f or example as battery electrode materials or electrocatalysts for fuel generation. Here,w er eport the tuning of the structure of transition-metal hydroxides and oxides by controlling chemical reactions using an unfocused laser to irradiate the precursor solution. AN d:YAGl aser with wavelengths of 532 nm or 1064 nm was used. The Ni 2+ ,M n 2+ ,a nd Co 2+ ion-containing aqueous solution undergoes photo-induced reactions and produces hollowm etal-oxide nanospheres (Ni 0.18 Mn 0.45 Co 0.37 O x)o rc ore-shell metal hydroxide nanoflowers ([Ni 0.15 Mn 0.15 Co 0.7 (OH) 2 ](NO 3) 0.2 •H 2 O), depending on the laser wavelengths.W ep ropose two reaction pathways, either by photo-induced redox reaction or hydrolysis reaction, which are responsible for the formation of distinct nanostructures.T he study of photon-induced materials growth shines light on the rational design of complex nanostructures with advanced functionalities.

Journal of the American Chemical Society, Jan 21, 2018

Attachment of N-heterocyclic carbenes (NHCs) on the surface of metal nanoparticle (NP) catalysts ... more Attachment of N-heterocyclic carbenes (NHCs) on the surface of metal nanoparticle (NP) catalysts permits fine-tuning of catalytic activity and product selectivity. Yet, NHC-coated Au NPs have been seldom used in catalysis beyond hydrogenation chemistry. One challenge in this field has been to develop a platform that permits arbitrary ligand modification without having to compromise NP stability toward aggregation or leaching. Herein, we exploit the strategy of supported dendrimer-encapsulated metal clusters (DEMCs) to achieve aggregation-stable yet active heterogeneous Au NP catalysts with NHC ligands. Dendrimers function as aggregation-inhibitors during the NP synthesis, and NHCs, well-known for their strong attachment to the gold surface, provide a handle to modify the stereochemistry, stereoelectronics, and chemical functionality of the NP surface. Indeed, compared to "ligandless" Au NPs which are virtually inactive below 80 °C, the NHC-ligated Au NP catalysts enable a ...

Proceedings of the National Academy of Sciences of the United States of America, Jan 10, 2016

Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nano... more Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nanoparticles. Model catalysts as such are applied to catalytic transformations in the three types of catalysts: heterogeneous, homogeneous, and enzymatic. Real-time dynamics of oxidation state, coordination, and bonding of nanoparticle catalysts are put under the microscope using surface techniques such as sum-frequency generation vibrational spectroscopy and ambient pressure X-ray photoelectron spectroscopy under catalytically relevant conditions. It was demonstrated that catalytic behavior and trends are strongly tied to oxidation state, the coordination number and crystallographic orientation of metal sites, and bonding and orientation of surface adsorbates. It was also found that catalytic performance can be tuned by carefully designing and fabricating catalysts from the bottom up. Homogeneous and heterogeneous catalysts, and likely enzymes, behave similarly at the molecular level. Unif...

Catalysts, heterogeneous, homogeneous, and enzymatic, are comprised of nanometer-sized inorganic ... more Catalysts, heterogeneous, homogeneous, and enzymatic, are comprised of nanometer-sized inorganic and/or organic components. They share molecular factors including charge, coordination, interatomic distance, bonding, and orientation of catalytically active atoms. By controlling the governing catalytic components and molecular factors, catalytic processes of a multichannel and multiproduct nature could be run in all three catalytic platforms to create unique end-products. Unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis. Recyclable catalysts, especially those that display selective reactivity, are vital for the development of sustainable chemical processes. Among available catalyst platforms, heterogeneous catalysts are particularly well-disposed toward separation from the reaction mixture via filtration methods, which renders them readily recyclable. Furthermore, heterogeneous catalysts offer numerous handles-some without homogeneous analogues-for performance and selectivity optimization. These handles include nanoparticle size, pore profile of porous supports, surface ligands and interface with oxide supports, and flow rate through a solid catalyst bed. Despite these available handles, however, conventional heterogeneous catalysts are themselves often structurally heterogeneous compared to homogeneous catalysts, which complicates efforts to optimize and expand the scope of their reactivity and selectivity. Ongoing efforts are aimed to address the above challenge by heterogenizing homogeneous catalysts, which can be defined as the modification of homogeneous catalysts to render them in a separable (solid) phase from the starting materials and products. Specifically, we grow the small nanoclusters in dendrimers, a class of uniform polymers with the connectivity of fractal trees and generally radial symmetry. Thanks to their dense multivalency, shape persistence and structural uniformity, dendrimers have 2 proven to be versatile scaffolds for the synthesis and stabilization of small nanoclusters. Then these dendrimer-encapsulated metal clusters (DEMCs) are adsorbed onto mesoporous silica. Through this method, we have achieved selective transformations that had been challenging to accomplish in a heterogeneous setting, e.g. π-bond activation and aldol reactions. Extensive investigation into the catalytic systems under reaction conditions allowed us to correlate the structural features (e.g. oxidation states) of the catalysts and their activity. Moreover, we have demonstrated that supported DEMCs are also excellent catalysts for typical heterogeneous reactions, including hydrogenation and alkane isomerization. Critically, these investigations also confirmed that the supported DEMCs are heterogeneous and stable against leaching. Catalysts optimization is achieved through the modulation of various parameters. The clusters are oxidized (e.g., with PhICl 2) or reduced (e.g., with H 2) in situ. Changing the dendrimer properties (e.g., generation, terminal functional groups) is analogous to ligand modification in homogeneous catalysts, which affect both catalytic activity and selectivity. Similarly, pore size of the support is another factor in determining product distribution. In a flow reactor, the flow rate is adjusted to control the residence time of the starting material and intermediates, and thus the final product selectivity. Our approach to heterogeneous catalysis affords various advantages: (1) the catalyst system can tap into the reactivity typical to homogeneous catalysts, which conventional heterogeneous catalysts could not achieve; (2) unlike most homogeneous catalysts with comparable performance, the heterogenized homogeneous catalysts can be recycled; (3) improved activity or selectivity compared to conventional homogeneous catalysts is possible because of uniquely heterogeneous parameters for optimization. While localized surface plasmon resonance (LSPR) provides a powerful platform for nanoparticle catalysis, our studies suggest that in some cases interband transitions should be considered as an alternative mechanism of light-driven nanoparticle catalysis. The benefits already demonstrated by plasmonic nanostructures as catalysts provided the impetus for examining complementary activation modes based on the metal nanoparticle itself. Leveraging these transitions has the potential to provide a means to highly active catalysis modes that would otherwise be challenging to access. For example, for the preparation of highly active metal catalysts on a subnanosized scale is challenging, thus limiting their exploitation and study in catalysis. Our work suggests a novel and facile strategy for the formation of highly active gold nanocluster catalysts by light illumination of the interband transitions in the presence of the appropriate substrate.

Nanoparticles (Pd, Pt, Rh) stabilized by G4OH PAMAM dendrimers and supported in SBA-15 (MNPs/SBA-... more Nanoparticles (Pd, Pt, Rh) stabilized by G4OH PAMAM dendrimers and supported in SBA-15 (MNPs/SBA-15 with M = Pd, Pt, Rh) were efficiently used as catalysts in the acceptorless dehydrogenation of tetrahydroquinoline/indoline derivatives in toluene (release of H 2) at 130 °C. These catalysts are air stable, very active, robust, and recyclable during the process. The reverse hydrogenation reaction of quinoline derivatives (H 2 storage) was also optimized and successfully performed in the presence of the same catalysts in toluene at 60 °C under only 1 atm of hydrogen gas. Such catalysts may be essential for the adoption of organic hydrogen-storage materials as an alternative to petroleum-derived fuels. Hot filtration test confirmed that the reaction follows a heterogeneous pathway. Moreover, PdNPs/SBA-15 was an excellent catalyst for the direct arylation at the C-2 position (via C−H activation) of indole in water in the presense of a hypervalent iodine oxidant. Thus, a one-pot dehydrogenation/direct arylation cascade reaction between indoline and an arylated agent was efficaciously performed in water, demonstrating the potential of the system to catalyze tandem heterogeneous/homogeneous processes by choice of the appropriate oxidant/reductant.

Heterogeneous catalysts have been widely used for chemical transformations and offer easy product... more Heterogeneous catalysts have been widely used for chemical transformations and offer easy product separation in addition to their high activity. Iron is an earth-abundant metal, but it has not been studied thoroughly as heterogeneous catalysts for organic reactions. In this work, supported iron catalysts were synthesized via loading FeCl 3 onto a mesoporous silica SBA-15. These catalysts were highly active for Michael addition reactions, a synthetic pathway for forming C C bonds that is typically achieved by homogeneous catalysts. Our studies show that for the supported iron catalysts, larger pore sizes of the silica resulting from the loading of iron and the oxidation state of iron being Fe(III) are essential for the high reaction rates. Notably, the catalysts show stability against leaching, regardless the presence or absence of a dendrimer as an additional stabilizing agent. The catalysts could be used for at least three runs without the loss of activity. The successful Michael addition reactions of indole or 2-methylindole and different ,ˇ-unsaturated ketones corroborate the synthetic scope of the catalysts. These results show promises of using supported iron catalysts as inexpensive and effective alternatives for the formation of C C bonds.

Supported molecular catalysts consist of nanomaterials immobilized on a solid support. Important ... more Supported molecular catalysts consist of nanomaterials immobilized on a solid support. Important factors that control catalyst properties (reactivity, product selectivity, and stability) include the structure and compositions of both nanomaterials and supports. This review focuses on recent studies of supported molecular catalysts with controlled activity and selectivity in our group. We will first introduce the development of previously unexplored supported molecular catalysts. We will demonstrate the controllable selectivity of catalysts based on acidified mesoporous silica, metal‐organic frameworks (MOFs), hydrogen‐activated tungsten oxides, and noble metal doped MnxOy/Na2WO4 catalyst supported on mesoporous silica. We will then discuss advanced characterization techniques under reaction conditions, which offer mechanistic explanations of activity and selectivity of supported molecular catalysts. The applications of chemical transient kinetics (CTK) analysis, ambient pressure X‐ray photoelectron spectroscopy (APXPS), and sum‐frequency generation vibrational spectroscopy (SFG‐VS) are discussed. Next, we will describe new insights into catalysis at the nanoparticle‐support interfaces, which are catalytic environments unique to supported molecular catalysts. Examples include reactions at oxide‐metal interfaces and alcohol oxidation reactions at solid–gas and solid–liquid interfaces. Lastly, we will discuss heterogenized homogeneous catalysts and heterogenized enzyme catalysts as future directions of supported molecular catalysts.

Attachment of N-heterocyclic carbenes (NHCs) on the surface of metal nanoparticle (NP) catalysts ... more Attachment of N-heterocyclic carbenes (NHCs) on the surface of metal nanoparticle (NP) catalysts permits fine-tuning of catalytic activity and product selectivity. Yet, NHC-coated Au NPs have been seldom used in catalysis beyond hydrogenation chemistry. One challenge in this field has been to develop a platform that permits arbitrary ligand modification without having to compromise NP stability toward aggregation or leaching. Herein, we exploit the strategy of supported dendrimer-encapsulated metal clusters (DEMCs) to achieve aggregation-stable yet active heterogeneous Au NP catalysts with NHC ligands. Dendrimers function as aggregation-inhibitors during the NP synthesis, and NHCs, well-known for their strong attachment to the gold surface, provide a handle to modify the stereochemistry, stereoelectronics, and chemical functionality of the NP surface. Indeed, compared to " ligandless " Au NPs which are virtually inactive below 80 °C, the NHC-ligated Au NP catalysts enable a model lactonization reaction to proceed at 20 °C on the same time scale (hours). Based on Eyring analysis, proto-deauration is the turnover-limiting step accelerated by the NHC ligands. Furthermore, the use of chiral NHCs led to asymmetric induction (up to 16% enantiomeric excess) in the lactonization transformations, which demonstrates the potential of supported DEMCs with ancillary ligands in enantioselective catalysis.

Catalysts are generally classified into three categories: homogeneous, heterogeneous and enzyme, ... more Catalysts are generally classified into three categories: homogeneous, heterogeneous and enzyme, each evolved as an independent field. Efforts to bridge these fields are scarce but desirable. In this Perspective, we first describe how numerous classes of reactions can be achieved by all three categories of catalysts. Examples are given based on a selective survey of the literature. Next, a selection of important approaches, the benefits and challenges of constructing heterogeneous–homogeneous, heterogeneous–enzyme and homogeneous–enzyme hybrid catalysts are discussed based on published researches. Hybrid catalysts not only increase the performance, including activity, selectivity, lifetime and recyclability compared to one of the components, but also offer extra functions such as a microenvironment for different reaction pathways, and cascade catalysis for products that are challenging to produce. We expect future tailor-made hybrid catalysts will combine the advantages of the components and be optimized for industrial applications.

Solar-driven photocatalytic conversion of CO 2 into fuels has attracted a lot of interest; howeve... more Solar-driven photocatalytic conversion of CO 2 into fuels has attracted a lot of interest; however, developing active catalysts that can selectively convert CO 2 to fuels with desirable reaction products remains a grand challenge. For instance, complete suppression of the competing H 2 evolution during photocatalytic CO 2-to-CO conversion has not been achieved before. We design and synthesize a spongy nickel-organic heterogeneous photocatalyst via a photochemical route. The catalyst has a crystalline network architecture with a high concentration of defects. It is highly active in converting CO 2 to CO, with a production rate of ~1.6 × 10 4 mmol hour −1 g −1. No measurable H 2 is generated during the reaction, leading to nearly 100% selective CO production over H 2 evolution. When the spongy Ni-organic catalyst is enriched with Rh or Ag nanocrystals, the controlled photocatalytic CO 2 reduction reactions generate formic acid and acetic acid. Achieving such a spongy nickel-organic photocatalyst is a critical step toward practical production of high-value multicarbon fuels using solar energy.

Light driven excitation of gold nanoparticles (GNPs) has emerged as a potential strategy to gener... more Light driven excitation of gold nanoparticles (GNPs) has emerged as a potential strategy to generate hot carriers for photocatalysis through excitation of localized surface plasmon resonance (LSPR). In contrast, carrier generation through excitation of interband transitions remains a less explored and underestimated pathway for photocatalytic activity. Photoinduced oxidative etching of GNPs with FeCl 3 was investigated as a model reaction in order to elucidate the effects of both types of transitions. The quantitative results show that interband transitions more efficiently generate hot carriers and that those carriers exhibit higher reactivity as compared to those generated solely by LSPR. Further, leveraging the strong π-acidic character of the resulting photogenerated Au + hole, an interband transition induced cyclization reaction of alkynylphenols was developed. Notably, alkyne coordination to the Au + hole intercepts the classic oxidation event and leads to the formation of the catalytically active gold clusters on subnanometer scale.

The effect of acidic properties of mesoporous zeolites on the control of product selectivity duri... more The effect of acidic properties of mesoporous zeolites on the control of product selectivity during the hydrogenative isomerization of methylcyclopentane has been investigated. A series of mesoporous zeolites with controlled acidic properties were prepared by postdealumination process with hydrochloric acid under hydrothermal conditions, and the resultant zeolites used for supporting colloidal Pt nanoparticles (NPs) with a mean size of 2.5 nm (±0.6 nm). As compared to the pure Pt NPs supported on catalytically inert mesoporous silica (MCF-17) as the reference catalyst that can produce isomers most selectively (∼80%), the Pt NPs supported on mesoporous zeolites produced C 6-cyclic hydrocarbons (i.e., cyclohexane and benzene) most dominantly. The type and strength of the Brö nsted (B) and Lewis (L) acid sites of those zeolites with a controlled Al amount are analyzed by using FT-IR after the adsorption of pyridine and NH 3 temperature-programmed desorption measurements, and they are correlated with the selectivity change between cyclohexane and benzene. From this investigation, we found a linear relationship between the number of Brö nsted acid sites and the formation rate for cyclohexane. In addition, we revealed that more Lewis acidic zeolite having relatively smaller B/L ratio is effective for the cyclohexane formation, whereas more Brö nsted acidic zeolite having relatively larger B/L ratio is effective for the benzene formation.

Controlled synthesis of transition-metal hydroxides and oxides with earth-abundant elements have ... more Controlled synthesis of transition-metal hydroxides and oxides with earth-abundant elements have attracted significant interest because of their wide applications,f or example as battery electrode materials or electrocatalysts for fuel generation. Here,w er eport the tuning of the structure of transition-metal hydroxides and oxides by controlling chemical reactions using an unfocused laser to irradiate the precursor solution. AN d:YAGl aser with wavelengths of 532 nm or 1064 nm was used. The Ni 2+ ,M n 2+ ,a nd Co 2+ ion-containing aqueous solution undergoes photo-induced reactions and produces hollowm etal-oxide nanospheres (Ni 0.18 Mn 0.45 Co 0.37 O x )o rc ore-shell metal hydroxide nanoflowers ([Ni 0.15 Mn 0.15 Co 0.7 (OH) 2 ](NO 3 ) 0.2 ·H 2 O), depending on the laser wavelengths.W ep ropose two reaction pathways, either by photo-induced redox reaction or hydrolysis reaction, which are responsible for the formation of distinct nanostructures.T he study of photon-induced materials growth shines light on the rational design of complex nanostructures with advanced functionalities.

Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nano... more Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nano-particles. Model catalysts as such are applied to catalytic transformations in the three types of catalysts: heterogeneous, homogeneous, and enzymatic. Real-time dynamics of oxidation state, coordination, and bonding of nanoparticle catalysts are put under the microscope using surface techniques such as sum-frequency generation vibrational spectroscopy and ambient pressure X-ray photoelectron spectroscopy under catalytically relevant conditions. It was demonstrated that catalytic behavior and trends are strongly tied to oxidation state, the coordination number and crystallographic orientation of metal sites, and bonding and orientation of surface adsorbates. It was also found that catalytic performance can be tuned by carefully designing and fabricating catalysts from the bottom up. Homogeneous and heterogeneous catalysts, and likely enzymes, behave similarly at the molecular level. Unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis.

Nano letters, Jan 16, 2016

The Hayashi-Ito aldol reaction of methyl isocyanoacetate (MI) and benzaldehydes, a classic homoge... more The Hayashi-Ito aldol reaction of methyl isocyanoacetate (MI) and benzaldehydes, a classic homogeneous Au(I)-catalyzed reaction, was studied with heterogenized homogeneous catalysts. Among dendrimer encapsulated nanoparticles (NPs) of Au, Pd, Rh, or Pt loaded in mesoporous supports and the homogeneous analogues, the Au NPs led to the highest yield and highest diastereoselectivity of products in toluene at room temperature. The Au catalyst was stable and was recycled for at least six runs without substantial deactivation. Moreover, larger pore sizes of the support and the use of a hydrophobic solvent led to a high selectivity for the trans diastereomer of the product. The activation energy is sensitive to neither the size of Au NPs nor the support. A linear Hammett plot was obtained with a positive slope, suggesting an increased electron density on the carbonyl carbon atom in the rate-limiting step. IR studies revealed a strong interaction between MI and the gold catalyst, supporting...

Nature Chemistry, 2023

Nature Communications, 2021

Science advances, 2017

Angewandte Chemie International Edition, 2016

Journal of the American Chemical Society, Jan 21, 2018

Proceedings of the National Academy of Sciences of the United States of America, Jan 10, 2016

Attachment of N-heterocyclic carbenes (NHCs) on the surface of metal nanoparticle (NP) catalysts ... more Attachment of N-heterocyclic carbenes (NHCs) on the surface of metal nanoparticle (NP) catalysts permits fine-tuning of catalytic activity and product selectivity. Yet, NHC-coated Au NPs have been seldom used in catalysis beyond hydrogenation chemistry. One challenge in this field has been to develop a platform that permits arbitrary ligand modification without having to compromise NP stability toward aggregation or leaching. Herein, we exploit the strategy of supported dendrimer-encapsulated metal clusters (DEMCs) to achieve aggregation-stable yet active heterogeneous Au NP catalysts with NHC ligands. Dendrimers function as aggregation-inhibitors during the NP synthesis, and NHCs, well-known for their strong attachment to the gold surface, provide a handle to modify the stereochemistry, stereoelectronics, and chemical functionality of the NP surface. Indeed, compared to " ligandless " Au NPs which are virtually inactive below 80 °C, the NHC-ligated Au NP catalysts enable a model lactonization reaction to proceed at 20 °C on the same time scale (hours). Based on Eyring analysis, proto-deauration is the turnover-limiting step accelerated by the NHC ligands. Furthermore, the use of chiral NHCs led to asymmetric induction (up to 16% enantiomeric excess) in the lactonization transformations, which demonstrates the potential of supported DEMCs with ancillary ligands in enantioselective catalysis.

Controlled synthesis of transition-metal hydroxides and oxides with earth-abundant elements have ... more Controlled synthesis of transition-metal hydroxides and oxides with earth-abundant elements have attracted significant interest because of their wide applications,f or example as battery electrode materials or electrocatalysts for fuel generation. Here,w er eport the tuning of the structure of transition-metal hydroxides and oxides by controlling chemical reactions using an unfocused laser to irradiate the precursor solution. AN d:YAGl aser with wavelengths of 532 nm or 1064 nm was used. The Ni 2+ ,M n 2+ ,a nd Co 2+ ion-containing aqueous solution undergoes photo-induced reactions and produces hollowm etal-oxide nanospheres (Ni 0.18 Mn 0.45 Co 0.37 O x )o rc ore-shell metal hydroxide nanoflowers ([Ni 0.15 Mn 0.15 Co 0.7 (OH) 2 ](NO 3 ) 0.2 ·H 2 O), depending on the laser wavelengths.W ep ropose two reaction pathways, either by photo-induced redox reaction or hydrolysis reaction, which are responsible for the formation of distinct nanostructures.T he study of photon-induced materials growth shines light on the rational design of complex nanostructures with advanced functionalities.

Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nano... more Colloidal chemistry is used to control the size, shape, morphology, and composition of metal nano-particles. Model catalysts as such are applied to catalytic transformations in the three types of catalysts: heterogeneous, homogeneous, and enzymatic. Real-time dynamics of oxidation state, coordination, and bonding of nanoparticle catalysts are put under the microscope using surface techniques such as sum-frequency generation vibrational spectroscopy and ambient pressure X-ray photoelectron spectroscopy under catalytically relevant conditions. It was demonstrated that catalytic behavior and trends are strongly tied to oxidation state, the coordination number and crystallographic orientation of metal sites, and bonding and orientation of surface adsorbates. It was also found that catalytic performance can be tuned by carefully designing and fabricating catalysts from the bottom up. Homogeneous and heterogeneous catalysts, and likely enzymes, behave similarly at the molecular level. Unifying the fields of catalysis is the key to achieving the goal of 100% selectivity in catalysis.

Nano letters, Jan 16, 2016