Jinlong Gong

Publications of Jinlong Gong

• Selective oxidation of methanol to dimethoxymethane over bifunctional VO(x)/TS-1 catalysts.

  Authors: Shuang Chen, Shengping Wang, Xinbin Ma, Jinlong Gong

  Chemical communications (Cambridge, England). 09/2011; 47(33):9345-7.

  This communication describes the design of bifunctional VO(x)/TS-1 catalysts with enhanced redox and acidic character via doping SO(4)(2-) and PO(4)(3-) for selective oxidation of methanol toThis communication describes the design of bifunctional VO(x)/TS-1 catalysts with enhanced redox and acidic character via doping SO(4)(2-) and PO(4)(3-) for selective oxidation of methanol to dimethoxymethane. Redox sites enable the production of formaldehyde, while acidic sites favor the condensation of formaldehyde to DMM.

• Recent advances in catalytic hydrogenation of carbon dioxide.

  Authors: Wei Wang, Shengping Wang, Xinbin Ma, Jinlong Gong

  Chemical Society reviews. 07/2011; 40(7):3703-27.

  Owing to the increasing emissions of carbon dioxide (CO(2)), human life and the ecological environment have been affected by global warming and climate changes. To mitigate the concentration of CO(2)Owing to the increasing emissions of carbon dioxide (CO(2)), human life and the ecological environment have been affected by global warming and climate changes. To mitigate the concentration of CO(2) in the atmosphere various strategies have been implemented such as separation, storage, and utilization of CO(2). Although it has been explored for many years, hydrogenation reaction, an important representative among chemical conversions of CO(2), offers challenging opportunities for sustainable development in energy and the environment. Indeed, the hydrogenation of CO(2) not only reduces the increasing CO(2) buildup but also produces fuels and chemicals. In this critical review we discuss recent developments in this area, with emphases on catalytic reactivity, reactor innovation, and reaction mechanism. We also provide an overview regarding the challenges and opportunities for future research in the field (319 references).

• Tuning porosity of Ti-MCM-41: implication for shape selective catalysis.

  Authors: Shengping Wang, Yun Shi, Xinbin Ma, Jinlong Gong

  ACS applied materials & interfaces. 06/2011; 3(6):2154-60.

  This paper describes a method to regulate porosity of Ti-containing mesoporous molecular sieves (Ti-MCM-41) by employing swelling agents that are hydrophobic in nature, such as dodecylamine,This paper describes a method to regulate porosity of Ti-containing mesoporous molecular sieves (Ti-MCM-41) by employing swelling agents that are hydrophobic in nature, such as dodecylamine, n-heptane, and sym-trimethylbenzene (TMB). Physicochemical properties of the samples were investigated using XRD, FT-IR, IR spectra of pyridine absorption, UV-vis, TEM, and N(2) adsorption-desorption techniques. Addition of favorable swelling agents leads to an increase in pore size accompanied by retaining the mesostructure with a certain decrease of structure ordering. Swelling agents also have significant impact on the integration of Ti into the silica framework, which further affect the formation of Lewis acid sites. N-heptane is the most favorable agent for pore expansion of Ti-MCM-41. The material with n-heptane/CTAB ratio of 1 exhibits the largest pore size of 48.3 Ǻ, and mesopore volume of 1.266 cm(3)/g and narrow pore-size distribution. We also demonstrated that shape-selective transesterification catalytic activity of Ti-MCM-41 was greatly enhanced because of pore expansion.

• Structure and Surface Chemistry of Gold-Based Model Catalysts.

  Authors: Jinlong Gong

  Chemical reviews. 04/2011;

• PEGylated liposome coated QDs/mesoporous silica core-shell nanoparticles for molecular imaging.

  Authors: Jie Pan, Dong Wan, Jinlong Gong

  Chemical communications (Cambridge, England). 02/2011; 47(12):3442-4.

  This paper describes the synthesis and application of PEGylated liposome-coated quantum dots (QDs)/mesoporous silica core-shell nanoparticles (NPs) for molecular imaging. This system increasesThis paper describes the synthesis and application of PEGylated liposome-coated quantum dots (QDs)/mesoporous silica core-shell nanoparticles (NPs) for molecular imaging. This system increases biocompatibility and stability of QDs, thus improving the imaging effects in labeling of cancer cells.

• CO dissociation induced by adsorbed oxygen and water on Ir(111).

  Authors: Ming Pan, Son Hoang, Jinlong Gong, C Buddie Mullins

  Chemical communications (Cambridge, England). 12/2009;

  Although CO does not dissociate on the clean Ir(111) surface, the addition of atomic oxygen induces CO dissociation at low temperatures (lower than 400 K); similarly, CO dissociation has also beenAlthough CO does not dissociate on the clean Ir(111) surface, the addition of atomic oxygen induces CO dissociation at low temperatures (lower than 400 K); similarly, CO dissociation has also been observed on water co-adsorbed Ir(111) or water and oxygen co-adsorbed Ir(111).

• Imaging Hindered Rotations of Alkoxy Species on TiO(2)(110).

  Authors: Zhenrong Zhang, Roger Rousseau, Jinlong Gong, Bruce D Kay, Zdenek Dohnálek

  Journal of the American Chemical Society. 11/2009;

  We present the first scanning tunneling microscopy (STM) study of the rotational dynamics of organic species on any oxide surface. Specifically, variable-temperature STM and dispersion-correctedWe present the first scanning tunneling microscopy (STM) study of the rotational dynamics of organic species on any oxide surface. Specifically, variable-temperature STM and dispersion-corrected density functional theory (DFT-D) are used to study the alkyl chain conformational disorder and dynamics of 1-, 2-, 3- and 4-octoxy on rutile TiO(2)(110). Initially, the geminate pairs of the octoxy and bridging hydroxyl species are created via octanol dissociation on bridging-oxygen (O(b)) vacancy defects. The STM images provide time-averaged snapshots of octoxy species rotating among multiple energetically nearly degenerate configurations accessible at a given temperature. In the calculations we find that the underlying corrugated potential energy surface is a result of the interplay between attractive van der Waals dispersion forces, leading to weak attractive C...Ti and repulsive C...O(b) interactions which lead to large barriers of 50-70 kJ mol(-1) for the rotation of the octoxy alkyl chains across the O(b) rows. In the presence of the geminate hydroxyl groups we find that the relative populations of the various conformations as well as the rotational barriers are perturbed by the presence of geminate hydroxyl due to additional C...hydroxyl repulsions.

• Oxygen exchange in the selective oxidation of 2-butanol on oxygen precovered Au(111).

  Authors: Ting Yan, Jinlong Gong, C Buddie Mullins

  Journal of the American Chemical Society. 11/2009; 131(44):16189-94.

  Direct evidence for C-O bond cleavage in the partial oxidation of 2-butanol on oxygen precovered Au(111) is provided using temperature programmed desorption (TPD) and molecular beam reactiveDirect evidence for C-O bond cleavage in the partial oxidation of 2-butanol on oxygen precovered Au(111) is provided using temperature programmed desorption (TPD) and molecular beam reactive scattering (MBRS) under ultrahigh vacuum (UHV) conditions. The oxygen precovered Au(111) surface can promote the partial oxidation of 2-butanol into 2-butanone with near 100% selectivity at low oxygen coverages, while 2-butanol adsorbs and desorbs molecularly on the clean Au(111) surface. Both C(2)H(5)C(16)OCH(3) and C(2)H(5)C(18)OCH(3) are observed in TPD after 2-butanol (C(2)H(5)CH(16)OHCH(3)) was dosed onto Au(111) precovered with (18)O(a). This oxygen exchange phenomenon serves as strong evidence for the C-O bond cleavage in 2-butanol partial oxidation to 2-butanone. Two surface intermediates are proposed for the selective oxidation of 2-butanol: 2-butoxide and eta(2)-aldehyde. As oxygen coverage increases, full oxidation is activated in addition to selective partial oxidation.

• Surface Science Investigations of Oxidative Chemistry on Gold.

  Authors: Jinlong Gong, C Buddie Mullins

  Accounts of chemical research. 08/2009;

  Because of gold's resistance to oxidation and corrosion, historically chemists have considered this metal inert. However, decades ago, researchers discovered that highly dispersed gold particles onBecause of gold's resistance to oxidation and corrosion, historically chemists have considered this metal inert. However, decades ago, researchers discovered that highly dispersed gold particles on metal oxides are highly chemically active, particularly in low-temperature CO oxidations. These seminal findings spurred considerable interest in investigations and applications of gold-based materials. Since the discovery of gold's chemical activity at the nanoscale, researchers found that bulk gold also has interesting catalytic properties. Thus, it is important to understand and contrast the intrinsic chemical properties of bulk gold with those of nanoparticle Au. Despite numerous studies, the structure and active site of supported Au nanoclusters and the active oxygen species remain elusive, and model studies under well-controlled conditions could help identify these species. The {111} facet has the lowest surface energy and is the most stable and prevalent configuration of most supported gold nanoparticles. Therefore, a molecular-level understanding of the physical properties and surface chemistry of Au(111) could provide mechanistic details regarding the nature of Au-based catalysts and lead to improved catalytic processes. This Account focuses on our current understanding of oxidative chemistry on well-defined gold single crystals, predominantly from recent investigations on Au(111) that we have performed using modern surface science techniques. Our model system strategy allows us to control reaction conditions, which assists in the identification of reaction intermediates, the determination of the elementary reaction steps, and the evaluation of reaction energetics for rate-limiting steps. We have employed temperature-programmed desorption (TPD), molecular beam reactive scattering (MBRS), and Auger electron spectroscopy (AES) to evaluate surface oxidative chemistry. In some cases, we have combined these results with density functional theory (DFT) calculations. By controlling the reaction parameters that determine product selectivity, we have examined the chemical properties of bulk gold. Based on our investigations, the surface-bound oxygen atoms are metastable at low temperature. We also demonstrate that the oxygen atoms and formed hydroxyls are responsible for some of the distinct chemical behavior of gold and participate in surface reactions either as a Brønsted base or a nucleophilic base. We observe similar reaction patterns on gold surfaces to those on copper and silver surfaces, suggesting that the acid-base reactions that have been observed on copper and silver may also occur on gold. Our model chemical studies on gold surfaces have provided intrinsic fundamental insights into high surface area gold-based catalysts and the origin of the reactive oxygen species.

• Selective oxidation of propylamine to propionitrile and propionaldehyde on oxygen-covered gold.

  Authors: Jinlong Gong, Ting Yan, C Buddie Mullins

  Chemical communications (Cambridge, England). 03/2009;

  Oxidative dehydrogenation of amines using heterogeneous gold catalysts has unanticipated potential; chemisorbed atomic oxygen is used to activate propylamine, producing propionitrile and/orOxidative dehydrogenation of amines using heterogeneous gold catalysts has unanticipated potential; chemisorbed atomic oxygen is used to activate propylamine, producing propionitrile and/or propionaldehyde on a single-crystal Au(111) surface.

• Selective oxidation of ethanol to acetaldehyde on gold.

  Authors: Jinlong Gong, C Buddie Mullins

  Journal of the American Chemical Society. 01/2009; 130(49):16458-9.

• Selective Oxidation of Ethanol to Acetaldehyde on Gold.

  Authors: Jinlong Gong, C Mullins

  Journal of the American Chemical Society. 12/2008;

• Selective Oxidation of Propanol on Au(111): Mechanistic Insights into Aerobic Oxidation of Alcohols.

  Authors: Jinlong Gong, David W Flaherty, Ting Yan, C Buddie Mullins

  Chemphyschem : a European journal of chemical physics and physical chemistry. 12/2008;

• Vacancy-assisted diffusion of alkoxy species on rutile TiO2(110).

  Authors: Zhenrong Zhang, Roger Rousseau, Jinlong Gong, Shao-Chun Li, Bruce D Kay, Qingfeng Ge, Zdenek Dohnálek

  Physical review letters. 10/2008; 101(15):156103.

  Using scanning tunneling microscopy (STM) and density functional theory simulations, we have studied the diffusion of alkoxy species formed by the dissociation of alcohols on bridge-bonded oxygenUsing scanning tunneling microscopy (STM) and density functional theory simulations, we have studied the diffusion of alkoxy species formed by the dissociation of alcohols on bridge-bonded oxygen (BBO) vacancies (BBO(V)'s) on TiO2(110). At elevated temperatures (>or=400 K) the sequential isothermal STM images show that mobile BBO(V)'s mediate the diffusion of alkoxy species by providing space for alkyl-group-bearing BBO atom to diffuse into. The experimental findings are further supported by simulations that find that BBO(V) diffusion is the rate limiting step in the overall diffusion mechanism.

• Carbonate formation and decomposition on atomic oxygen precovered Au(111).

  Authors: Rotimi A Ojifinni, Jinlong Gong, Nathan S Froemming, David W Flaherty, Ming Pan, Graeme Henkelman, C Buddie Mullins

  Journal of the American Chemical Society. 09/2008; 130(34):11250-1.

  Experimental results supported by density functional theory calculations show carbonate formation and reaction on atomic oxygen precovered Au(111). Oxygen mixing is observed in temperature-programmedExperimental results supported by density functional theory calculations show carbonate formation and reaction on atomic oxygen precovered Au(111). Oxygen mixing is observed in temperature-programmed desorption measurements when a Au(111) precovered with 16O is exposed to isotopically labeled CO2 (C18O2). The presence of 16O18O is attributed to surface carbonate formation and decomposition at surface temperatures ranging from 77-400 K and initial oxygen coverages ranging from 0.18-2.1 ML. A reaction probability on the order of 10(-4) and an activation energy of -0.15+/- 0.08 eV are estimated for this reaction.

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• Water-enhanced low-temperature CO oxidation and isotope effects on atomic oxygen-covered Au(111).

  Authors: Rotimi A Ojifinni, Nathan S Froemming, Jinlong Gong, Ming Pan, Tae S Kim, J M White, Graeme Henkelman, C Buddie Mullins

  Journal of the American Chemical Society. 06/2008; 130(21):6801-12.

  Water-oxygen interactions and CO oxidation by water on the oxygen-precovered Au(111) surface were studied by using molecular beam scattering techniques, temperature-programmed desorption (TPD), andWater-oxygen interactions and CO oxidation by water on the oxygen-precovered Au(111) surface were studied by using molecular beam scattering techniques, temperature-programmed desorption (TPD), and density functional theory (DFT) calculations. Water thermally desorbs from the clean Au(111) surface with a peak temperature of approximately 155 K; however, on a surface with preadsorbed atomic oxygen, a second water desorption peak appears at approximately 175 K. DFT calculations suggest that hydroxyl formation and recombination are responsible for this higher temperature desorption feature. TPD spectra support this interpretation by showing oxygen scrambling between water and adsorbed oxygen adatoms upon heating the surface. In further support of these experimental findings, DFT calculations indicate rapid diffusion of surface hydroxyl groups at temperatures as low as 75 K. Regarding the oxidation of carbon monoxide, if a C (16)O beam impinges on a Au(111) surface covered with both atomic oxygen ( (16)O) and isotopically labeled water (H 2 (18)O), both C (16)O (16)O and C (16)O (18)O are produced, even at surface temperatures as low as 77 K. Similar experiments performed by impinging a C (16)O beam on a Au(111) surface covered with isotopic oxygen ( (18)O) and deuterated water (D 2 (16)O) also produce both C (16)O (16)O and C (16)O (18)O but less than that produced by using (16)O and H 2 (18)O. These results unambiguously show the direct involvement and promoting role of water in CO oxidation on oxygen-covered Au(111) at low temperatures. On the basis of our experimental results and DFT calculations, we propose that water dissociates to form hydroxyls (OH and OD), and these hydroxyls react with CO to produce CO 2. Differences in water-oxygen interactions and oxygen scrambling were observed between (18)O/H 2 (16)O and (18)O/D 2 (16)O, the latter producing less scrambling. Similar differences were also observed in water reactivity toward CO oxidation, in which less CO 2 was produced with (16)O/D 2 (16)O than with (16)O/H 2 (16)O. These differences are likely due to primary kinetic isotope effects due to the differences in O-H and O-D bond energies.

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• Reactivity of molecularly chemisorbed oxygen on a Au/TiO2 model catalyst.

  Authors: James D Stiehl, Jinlong Gong, Rotimi A Ojifinni, Tae S Kim, Sean M McClure, C Buddie Mullins

  The journal of physical chemistry. B. 11/2006; 110(41):20337-43.

  We present results of an investigation into the reactivity of molecularly chemisorbed oxygen with CO on a Au/TiO2 model catalyst at 77 K. We previously discovered that exposing the model catalystWe present results of an investigation into the reactivity of molecularly chemisorbed oxygen with CO on a Au/TiO2 model catalyst at 77 K. We previously discovered that exposing the model catalyst sample to a radio-frequency-generated plasma jet of oxygen results in co-population of both atomically and molecularly chemisorbed oxygen species on the sample. We tested the reactivity of the molecularly chemisorbed oxygen by comparing the CO2 produced from a sample populated with both species to the CO2 produced from a sample that has been cleared of molecularly chemisorbed oxygen employing collision-induced desorption. Samples that are populated with both species consistently result in greater CO2 produced than samples with only atomic oxygen. We interpret this result to indicate that molecularly chemisorbed oxygen on the sample can directly participate in the CO oxidation reaction. The reactivity of molecularly chemisorbed oxygen has been investigated for five different gold coverages (0.5, 0.75, 1, 1.25, and 2 ML), and we observe that there is a greater fractional difference in the CO2 produced (difference between sample populated with both molecularly and atomically adsorbed oxygen and sample populated solely with atomically adsorbed oxygen) for the 1 ML Au coverage than for the other coverages for equivalent oxygen plasma-jet exposures. However, it is not possible to unambiguously conclude that this observation is directly related to a particle size effect on the chemistry since the absolute O(2,a) and O(a) content on the various surfaces is different for all the coverages studied because of the plasma-jet technique that we employed for populating the surfaces with oxygen. Unfortunately, this precludes a direct comparison of the reactivity of molecular oxygen in the carbon monoxide oxidation reaction as a function of gold coverage and hence particle size.

• Selective catalytic oxidation of ammonia to nitrogen on atomic oxygen precovered Au(111).

  Authors: Jinlong Gong, Rotimi A Ojifinni, Tae S Kim, John M White, C Buddie Mullins

  Journal of the American Chemical Society. 08/2006; 128(28):9012-3.

  We demonstrate ammonia oxidation promoted by an atomic oxygen precovered Au(111) surface. The selectivity of the catalytic oxidation of ammonia to NO or N2 on Au(111) is tunable by the atomic oxygenWe demonstrate ammonia oxidation promoted by an atomic oxygen precovered Au(111) surface. The selectivity of the catalytic oxidation of ammonia to NO or N2 on Au(111) is tunable by the atomic oxygen coverage. We propose that N2 and NO are produced via the recombination reactions of Nad + Nad and Nad + Oad.

• Water activated by atomic oxygen on Au(111) to oxidize CO at low temperatures.

  Authors: Tae S Kim, Jinlong Gong, Rotimi A Ojifinni, J M White, C Buddie Mullins

  Journal of the American Chemical Society. 06/2006; 128(19):6282-3.

  The Au(111) surface was populated with atomic oxygen [16O] followed by oxygen-labeled water [H218O] at surface temperatures as low as 77 K. When a CO beam was impinged on this surface, both [C16O16O]The Au(111) surface was populated with atomic oxygen [16O] followed by oxygen-labeled water [H218O] at surface temperatures as low as 77 K. When a CO beam was impinged on this surface, both [C16O16O] and [C16O18O] were produced. The results strongly suggest the direct involvement and promoting role of water in CO oxidation on oxygen covered Au(111) at low temperatures.

• Phosgene-free approaches to catalytic synthesis of diphenyl carbonate and its intermediates

  Authors: Jinlong Gong, Xinbin Ma, Shengping Wang

  Applied Catalysis A: General. 316(1):1-21.

  Diphenyl carbonate (DPC) is considered as a substitution for phosgene to synthesize polycarbonate resins. Conventional production of DPC involves reactions of phosgene and phenol. However, theDiphenyl carbonate (DPC) is considered as a substitution for phosgene to synthesize polycarbonate resins. Conventional production of DPC involves reactions of phosgene and phenol. However, the phosgene process has drawbacks such as environmental and safety problems associated with using highly toxic phosgene as the reagent, which results in the formation of chlorine salts, and copious amounts of methylene chloride as the solvent. For these reasons, environmentally friendly processes for DPC production without using phosgene have been proposed and developed in the past decades. So far, the most promising alternatives appear to be the transesterification of dimethyl carbonate (DMC) and phenol, the direct oxidative carbonylation of phenol, and transesterification of dialkyl oxalates and phenol. This paper attempts to review recent literature concerning process design and catalytic chemistry for these phosgene-free approaches. The advantages and disadvantages are discussed for each reaction. Strategies to