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Gerard H. Hoveling

Bio: Gerard H. Hoveling is an academic researcher from Delft University of Technology. The author has contributed to research in topics: Chemical process & Scanning transmission X-ray microscopy. The author has an hindex of 1, co-authored 1 publications receiving 334 citations.

Papers
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Journal ArticleDOI
13 Nov 2008-Nature
TL;DR: Scanning transmission X-ray microscopy can be used at atmospheric pressure and up to 350 °C to monitor in situ phase changes in a complex iron-based Fisher–Tropsch catalyst and the nature and location of carbon species produced.
Abstract: The modern chemical industry uses heterogeneous catalysts in almost every production process. They commonly consist of nanometre-size active components (typically metals or metal oxides) dispersed on a high-surface-area solid support, with performance depending on the catalysts' nanometre-size features and on interactions involving the active components, the support and the reactant and product molecules. To gain insight into the mechanisms of heterogeneous catalysts, which could guide the design of improved or novel catalysts, it is thus necessary to have a detailed characterization of the physicochemical composition of heterogeneous catalysts in their working state at the nanometre scale. Scanning probe microscopy methods have been used to study inorganic catalyst phases at subnanometre resolution, but detailed chemical information of the materials in their working state is often difficult to obtain. By contrast, optical microspectroscopic approaches offer much flexibility for in situ chemical characterization; however, this comes at the expense of limited spatial resolution. A recent development promising high spatial resolution and chemical characterization capabilities is scanning transmission X-ray microscopy, which has been used in a proof-of-principle study to characterize a solid catalyst. Here we show that when adapting a nanoreactor specially designed for high-resolution electron microscopy, scanning transmission X-ray microscopy can be used at atmospheric pressure and up to 350 degrees C to monitor in situ phase changes in a complex iron-based Fisher-Tropsch catalyst and the nature and location of carbon species produced. We expect that our system, which is capable of operating up to 500 degrees C, will open new opportunities for nanometre-resolution imaging of a range of important chemical processes taking place on solids in gaseous or liquid environments.

364 citations


Cited by
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Journal ArticleDOI
TL;DR: This Review concludes with a conclusion that further research is needed into the determinants of infectious disease and the immune system in order to treat these diseases and provide effective treatments.
Abstract: We gratefully acknowledge funding and support from King Abdullah University of Science and Technology (KAUST). Thanks are also due to the KAUST communication department for designing several images for this Review.

1,497 citations

Journal ArticleDOI
TL;DR: In this article, the authors focus on the use of nano-catalysis for green chemistry development including the strategy of using microwave heating with nanocatalysis in benign aqueous reaction media which offers an extraordinary synergistic effect with greater potential than these three components in isolation.

1,005 citations

Journal ArticleDOI
TL;DR: In this paper, the major routes for the production of lower olefins from synthesis gas with an emphasis on a direct or single step process, the so-called Fischer-Tropsch to olefin process, is described.
Abstract: C2 to C4 olefins are traditionally produced from steam cracking of naphtha. The necessity for alternative production routes for these major commodity chemicals via non-oil-based processes has driven research in past times during the oil crises. Currently, there is a renewed interest in producing lower olefins from alternative feedstocks such as coal, natural gas, or biomass, in view of high oil prices, environmental regulations, and strategies to gain independence from oil imports. This review describes the major routes for the production of lower olefins from synthesis gas with an emphasis on a direct or single step process, the so-called FTO or Fischer–Tropsch to olefins process. The different catalysts for FTO are outlined and compared, and the key issues and requirements for future developments are highlighted. Iron-based catalysts are prevailing for FTO, and reproducible lower olefin selectivities of 50 wt % of hydrocarbons produced have been realized at CO conversions higher than 70% for 60 to 1000 ...

738 citations

Journal ArticleDOI
TL;DR: This critical review deals with the applications of nanocatalysts in Suzuki coupling reactions, a field that has attracted immense interest in the chemical, materials and industrial communities, with an emphasis on their performance, stability and reusability.
Abstract: This critical review deals with the applications of nanocatalysts in Suzuki coupling reactions, a field that has attracted immense interest in the chemical, materials and industrial communities. We intend to present a broad overview of nanocatalysts for Suzuki coupling reactions with an emphasis on their performance, stability and reusability. We begin the review with a discussion on the importance of Suzuki cross-coupling reactions, and we then discuss fundamental aspects of nanocatalysis, such as the effects of catalyst size and shape. Next, we turn to the core focus of this review: the synthesis, advantages and disadvantages of nanocatalysts for Suzuki coupling reactions. We begin with various nanocatalysts that are based on conventional supports, such as high surface silica, carbon nanotubes, polymers, metal oxides and double hydroxides. Thereafter, we reviewed nanocatalysts based on non-conventional supports, such as dendrimers, cyclodextrin and magnetic nanomaterials. Finally, we discuss nanocatalyst systems that are based on non-conventional media, i.e., fluorous media and ionic liquids, for use in Suzuki reactions. At the end of this review, we summarise the significance of nanocatalysts, their impacts on conventional catalysis and perspectives for further developments of Suzuki cross-coupling reactions (131 references).

702 citations

Journal ArticleDOI
TL;DR: In this article, the authors proposed a method to use the key scientific project of Fujian Province to improve the performance of the Key Scientific Project (KSP) of the National Natural Science Foundation of China (NNSF).
Abstract: National Natural Science Foundation of China [20625310, 20923004]; National Basic Research Program of China [2005CB221408, 2010CB732303]; Research Fund for the Doctoral Program of Higher Education [20090121110007]; Key Scientific Project of Fujian Province [2009HZ0002-1]

664 citations