Inkjet Printing of Catalytic Materials

During the last four decades, inkjet printing has become one of the most prevalent printing technologies for home and office desktop printing applications. Advances in inkjet technology allow the printing of full-color, high-resolution photographs of equivalent quality to those from other printing techniques that have prevailed in the recent past. In the commercial printing sector, inkjet technology is being widely used for digital proofing prior to running a print job on a press; for short-run, wide-format digital printing such as posters for outdoor advertising; and for applications that require printing onto non-paper substrates such as rigid display boards. In addition, inkjet printers are being developed for integration with offset presses to print customized information in magazines, such as tailored advertising (Sirringhaus & Shimoda, 2003). Finally, in the general industrial sector, the inkjet technology is considered as the leading technology for printing customized information such as “sell-by” dates and product identification codes, as part of packaging or production processes

Hydrogen Lean-DeNOx as an Alternative to the Ammonia and Hydrocarbon Selective Catalytic Reduction (SCR)

The present article consists a critical up-to-date review of the research conducted so far on the selective catalytic reduction of NOx with hydrogen under lean-burn conditions as an alternative technology to the existing NH3- and HC-SCR. Noble Metal based catalysts are described in detail with emphasis on the analysis of the various reaction mechanisms that have been put forward in the literature. The influence of the nature of the support chemical composition and the preparation method and structure of the catalysts on the reaction mechanism is also discussed. Finally, the effects of various reaction parameters on the catalysts activity, selectivity and stability with reaction time are discussed in detail

The influence of reaction temperature on the chemical structure and surface concentration of active nox in h2-scr over pt/mgo{single bond}ceo2: ssitka-drifts and transient mass spectrometry studies

Steady-state isotopic transient kinetic analysis (SSITKA), transient isothermal, and temperature-programmed surface reaction in H2 (H2-TPSR) techniques coupled with online mass spectroscopy (MS) and in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) were used to study essential mechanistic and kinetic aspects of the selective catalytic reduction (SCR) of NO with the use of H2 under strongly oxidizing conditions (H2-SCR) over a novel Pt/MgO{single bond}CeO2 catalyst. The main focus was to study and report for the first time the effects of reaction temperature on the chemical structure and surface concentration of the active NOx intermediate species thereby formed. The information obtained is essential to understanding the volcano-type profile of the catalyst activity versus reaction temperature observed here and also reported previously. In the present work, two active NOx intermediate species identified by SSITKA-DRIFTS were found in the nitrogen-reaction path toward N2 and N2O formation, one species located in the vicinity of the Pt{single bond}CeO2 support interface region (nitrosyl [NO+] coadsorbed with a nitrate [NO-3] species on an adjacent Ce4+{single bond}O2- site pair) and the second located in the vicinity of the Pt{single bond}MgO support interface region. The chemical structure of the second kind of active NOx species was found to depend on reaction temperature. In particular, the chemical structure was that of bidentate or monodentate nitrate (NO-3) at T 200 ° C. The concentration of the active NOx intermediates that lead to N2 formation was found to be practically independent of reaction temperature (120-300 °C) and significantly larger than 1 equivalent monolayer of surface Pt (θNOx = 2.4 - 2.6). The former result cannot be used to explain the volcano-type behavior of the catalytic activity versus the reaction temperature observed; alternative explanations are explored. The H-spillover process involved in the H2-SCR mechanism was found to be limited within a support region of about a 4-5 Å radius around the Pt nanoparticles (dPt = 1.2 - 1.5 nm)

An investigation of the NO/H2/O2 (Lean De-NOx) reaction on a highly active and selective Pt/La0.7Sr0.2Ce0.1FeO3 catalyst at low temperatures

A 0.1 wt% Pt supported on La0.7Sr0.2Ce0.1FeO3 solid (mixed oxide containing LaFeO3, SrFeO3-x, CeO2, and Fe2O3 phases) has been studied for the NO/H2/O2 reaction in the 100-400°C range. For a critical comparison, 0.1 wt% Pt was supported on SiO2, CeO2, and Fe2O3 and tested under the same reaction conditions. For the Pt/La0.7Sr0.2Ce0.1FeO3 catalyst a maximum in the NO conversion (83%) has been observed at 150°C with a N2 selectivity value of 93%, while for the Pt/SiO2 catalyst at 120°C (82% conversion) with a N2 selectivity value of 65% using a GHSV of 80,000 h-1 Low N2 selectivity values, less than 45%, were obtained with the Pt/CeO2 and Pt/Fe2O3 catalysts in the 100-400°C range. For the Pt/La0.7Sr0.2Ce0.1FeO3 catalyst, addition of 5% H2O in the feed stream at 140°C resulted in a widening of the operating temperature window with appreciable NO conversion and no negative effect on the stability of the catalyst during 20 h on stream. In addition, a remarkable N2 yield (93%) after 20 h on 0.25% NO/1% H2/5% O2/5% H2O/He gas stream at 140°C has been observed. Remarkable N2 selectivity values in the range of 80-90% have also been observed in the 100-200°C low-temperature range either in the absence or in the presence of water in the feed stream. A maximum specific integral reaction rate of 443.5 μmol N2/s·g of Pt metal was measured at 160°C during reaction with a 0.25% NO/1% H2/5% O2/5% H2O/He gas mixture. This value is higher by 90% than the corresponding one observed on the 0.1 wt% Pt/SiO2 catalyst at 120°C and it is the highest value ever reported for the reaction at hand in the 100-200°C low-temperature range on Pt-based catalysts. A TOF value of 13.4 × 10-2 s-1 for N2 formation was calculated at 110°C for the Pt/La0.7Sr0.2Ce0.1FeO3 catalyst. Temperature-programmed desorption (TPD) of NO and transient titration experiments of the catalyst surface following NO/H2/O2 reaction have revealed important information concerning the amount and chemical composition of active and inactive (spectator) adsorbed N-containing species present under reaction conditions

A Complete Techno-Economical Assessment for the Conversion of the Kotsiatis Landfill in Cyprus into a Waste to Energy Plant

Human activities give rise to waste materials, which if not recycled or reused, end up in landfills as "waste". Cyprus is one of the new Member States of the European Union and before 2003, specific legislation concerning the safe management of waste was absent, with most of the waste ending up in landfills. The largest landfill in Cyprus, Kotsiatis, is located 17 km from Nicosia, occupying an area of 2ha. The current study focuses on a complete techno-economical assessment concerning the conversion of Kotsiatis into a modem Waste-to-Energy (WtE) plant, including aspects such as marketing and promotional activities needed, financing options and operational costs. Results have shown that the construction of a Waste-to-Energy plant in the area will improve the quality of life and the current environmental problems, and that it is economically viable without governmental subsidy (with a Net Present Value of €2,655,730 and an Internal Rate of Return of 10.5% in our base scenario). Finally, even though the locals in the close vicinity are against such a plant, this is due to them not being aware of the technology and being misinformed by information through local media

Catalytic removal of nitrates from waters in a continuous flow process: The remarkable effect of liquid flow rate and gas feed composition

The selective catalytic reduction of nitrates (NO3 -) in water mediums towards N2 formation by the use of H2 and in the presence of O2 (air) in the gas feed has been investigated under a continuous flow process over Pd-Cu supported on various mixed metal oxides, xwt.% MxOy/g-Al2O3 (MxOy=CeO2, MgO, Mn2O3, Cr2O3, Y2O3, MoO2, Fe2O3 and TiO2). It is demonstrated for the first time that a remarkable improvement of both catalysts activity and N2 reaction selectivity can be achieved when increasing the liquid flow rate in the continuous flow process. In particular, it was found that NO3 - reduction rates up to more than two times higher and NH4 selectivity values up to twenty times lower can be obtained when increasing the liquid flow rate from 2 to 6mL/min. Moreover, it was proven for the first time, in a continuous flow process, that the presence of oxygen (or air) has a remarkable positive effect on the reaction's selectivity towards nitrogen. The reaction's selectivity towards NH4 can be decreased by up to three times when 20vol.% air is added in the gas feed of the NO3 -/H2 continuous flow reaction. The Pd-Cu clusters supported on TiO2-, CeO2- and MgO-coated g-Al2O3 spheres showed the best catalytic behaviour compared with the rest of supports examined, both in the presence and in the absence of oxygen in the reducing feed gas stream. In addition, it was found that the initial concentration of nitrates in the liquid feed can significantly affect catalysts activity and reaction's selectivity. A positive apparent reaction order towards nitrates of 0.9 was calculated on Pd-Cu/TiO2/Al2O3. 2010 Elsevier B.V

The mechanism of reduction of NO with H2 in strongly oxidizing conditions (H2-SCR) on a novel Pt/MgO-CeO2 catalyst: Effects of reaction temperature

Presented at III International Conference on Catalysis: Fundamentals and Applications, 2007, 4-8 July, Novosibirsk, RussiaSteady State Isotopic Transient Kinetic Analysis (SSITKA) experiments using on-line Mass Spectrometry (MS) and in situ Diffuse Reflectance Infrared Fourier-Transform Spectroscopy (DRIFTS) have been performed to study essential mechanistic aspects of the Selective Catalytic Reduction of NO by H2 under strongly oxidizing conditions (H2-SCR) in the 120–300°C range over a novel 0.1 wt % Pt/MgO-CeO2 catalyst. The N-path of reaction from NO to the N2 gas product was probed by following the 14NO/H2O2 → 15NO/H2/O2 switch (SSITKA-MS and SSITKA-DRIFTS) at 1 bar total pressure. It was found that the N-pathway of reaction involves the formation of two active NO x species different in structure, one present on MgO and the other one on the CeO2 support surface. Inactive adsorbed NO x species were also found on both the MgO-CeO2 support and the Pt metal surfaces. The concentration (mol/g cat) of active NO x leading to N2 was found to change only slightly with reaction temperature in the 120–300°C range. This leads to the conclusion that other intrinsic kinetic reasons are responsible for the volcano-type conversion of NO versus the reaction temperature profile observed