Author
M.I. Pais da Silva
Bio: M.I. Pais da Silva is an academic researcher from Pontifical Catholic University of Rio de Janeiro. The author has contributed to research in topics: Catalysis & Zeolite. The author has an hindex of 9, co-authored 15 publications receiving 293 citations.
Papers
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TL;DR: In this paper, bimetallic catalysts were more active toward the C2−C4 hydrocarbon fraction, with an enhancement in the selectivity to C2, C3 and 1-C4 olefins.
Abstract: Fischer–Tropsch synthesis (493 K, 0.62 MPa CO, 1.24 MPa H2) has been performed over monometallic and bimetallic Co and/or Fe clusters deposited on mesoporous silicas (HMS and SBA-15). Catalysts have been prepared by incipient wetness impregnation and characterized by N2 adsorption–desorption isotherms, X-ray diffraction (XRD), H2-temperature programmed reduction (H2-TPR), and transmission electron microscopy (TEM). HMS supported Co-Fe catalyst showed the highest activity and C5+ hydrocarbon selectivity, while Co-Fe/SBA-15 catalyst revealed the highest selectivity to alcohols. Both bimetallic catalysts were more active toward the C2–C4 hydrocarbon fraction, with an enhancement in the selectivity to C2 , C3 and 1-C4 olefins. Both bimetallic catalysts showed greater chain growth probability values than the monometallic iron based catalysts although their performance in catalytic tests were more close to the iron catalyst.
62 citations
TL;DR: In this article, the performance of methanol synthesis catalysts based on Cu-Zn-Al was studied in the direct synthesis of DME using H-ferrierite as a dehydration component.
61 citations
TL;DR: In this article, three preparation methods (coprecipitation, sequential precipitation, and homogeneous precipitation) were evaluated in a methanol steam reforming reaction and the authors concluded that the preparation methods used influenced Cu dispersion and overall catalyst structure, and Cu-Zn alloy formation resulted from the incorporation of Zn atoms into the Cu lattice.
47 citations
TL;DR: In this article, a co-precipitation method was used in methanol steam reforming at 250˚°C and ZrO2 nanoclusters or amorphous material was found in Zr-based catalyst which role was to prevent the CuO and ZnO crystallite growth causing a microstrain in Cu oxides lattice.
33 citations
TL;DR: In this article, the acidity of H-ferrierite (H-FER) zeolite with different Si/Al ratios was obtained through several dealumination methods: calcination, steam treatment, acid leaching after steam treatment and ionic exchange with ammonium and silicon hexafluoride.
30 citations
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TL;DR: In this paper, the authors present recent developments in synthesis methods of dimethyl ether as an alternative energy while focusing on conventional processes and innovative technologies in reactor design and employed catalysts.
Abstract: Dimethyl ether (DME) is a well-known propellant and coolant, an alternative clean fuel for diesel engines which simultaneously is capable of achieving high performance and low emission of CO, NOx and particulates in its combustion. It can be produced from a variety of feed-stocks such as natural gas, coal or biomass; and also can be processed into valuable co-products such as hydrogen as a sustainable future energy. This review, which also can be counted as an extensive, pioneer review paper on this topic, presents recent developments in synthesis methods of dimethyl ether as an alternative energy while focuses on conventional processes and innovative technologies in reactor design and employed catalysts. In this context, synthesis methods are classified according to their use of raw material type as direct and indirect methods as well as other routes, since different methods need their own operating condition. Also, the available data for the selectivity to DME and its yield as a function of H2/CO and CO2 content of the feed is discussed.
386 citations
TL;DR: State-of-the-art oxidative lignin depolymerization chemistries employed in the papermaking process and oxidative catalysts that can be applied to biorefinery lignIn to produce platform chemicals including phenolic compounds, dicarboxylic acids, and quinones in high selectivity and yield are reviewed.
Abstract: Transforming plant biomass to biofuel is one of the few solutions that can truly sustain mankind's long-term needs for liquid transportation fuel with minimized environmental impact. However, despite decades of effort, commercial development of biomass-to-biofuel conversion processes is still not an economically viable proposition. Identifying value-added co-products along with the production of biofuel provides a key solution to overcoming this economic barrier. Lignin is the second most abundant component next to cellulose in almost all plant biomass; the emerging biomass refinery industry will inevitably generate an enormous amount of lignin. Development of selective biorefinery lignin-to-bioproducts conversion processes will play a pivotal role in significantly improving the economic feasibility and sustainability of biofuel production from renewable biomass. The urgency and importance of this endeavor has been increasingly recognized in the last few years. This paper reviews state-of-the-art oxidative lignin depolymerization chemistries employed in the papermaking process and oxidative catalysts that can be applied to biorefinery lignin to produce platform chemicals including phenolic compounds, dicarboxylic acids, and quinones in high selectivity and yield. The potential synergies of integrating new catalysts with commercial delignification chemistries are discussed. We hope the information will build on the existing body of knowledge to provide new insights towards developing practical and commercially viable lignin conversion technologies, enabling sustainable biofuel production from lignocellulosic biomass to be competitive with fossil fuel.
371 citations
TL;DR: In this article, a review illustrates the earlier state-of-the-art from an experimental point of view about hydrogen production from methanol reforming performed in both conventional and membrane reactors.
Abstract: In the recent years, hydrogen has gained a considerable interest as an energy carrier useful for various applications and, particularly, for polymer electrolyte membrane fuel cells (PEMFCs) supply. Nevertheless, PEMFCs require high purity hydrogen as a feeding fuel, which shows some limitations regarding storage and transportation. Therefore, to overcome these problems, the in situ hydrogen generation has made attractive both alcohols and hydrocarbons steam reforming reaction. Among other fuels, methanol is an interesting hydrogen source because it is liquid at ambient conditions, possesses relatively high H/C ratio, low reforming temperature (200–300 °C) and it is also producible from biomass. Meanwhile, there is a comprehensive literature about inorganic membrane reactors utilization for hydrogen generation via methanol steam reforming reaction. This review illustrates the earlier state of the art from an experimental point of view about hydrogen production from methanol reforming performed in both conventional and membrane reactors. Furthermore, a short overview about methanol reforming catalysts as well as a discussion on the impact of methanol steam reforming process via inorganic membrane reactors to produce hydrogen for PEMFCs supply is given.
355 citations
TL;DR: In this review, various aspects of chitin research including sources, structure, biosynthesis, chitinolytic enzyme, Chitin binding protein, genetic engineering approach to produce chit in, ch itin and evolution, and a wide range of applications in bio- and nanotechnology will be dealt with.
Abstract: Two centuries after the discovery of chitin, it is widely accepted that this biopolymer is an important biomaterial in many aspects. Numerous studies on chitin have focused on its biomedical applications. In this review, various aspects of chitin research including sources, structure, biosynthesis, chitinolytic enzyme, chitin binding protein, genetic engineering approach to produce chitin, chitin and evolution, and a wide range of applications in bio- and nanotechnology will be dealt with.
341 citations
TL;DR: The presence of light and heavy metal ions influenced the copper and cobalt uptake potential of crab shell and among several eluting agents, EDTA (pH 3.5, in HCl) performed well and also caused low biosorbent damage.
339 citations