Special Issue "Catalysis in Steam Reforming"

A special issue of Catalysts (ISSN 2073-4344).

Deadline for manuscript submissions: closed (31 October 2018)

Special Issue Editor

Guest Editor
Dr. Valerie Dupont

Energy Research Institute, School of Chemical and Process Engineering, The University of Leeds, Leeds, LS2 9JT, UK
Website | E-Mail
Interests: gas solid catalysis; energy analysis; process and reactor simulation; chemical looping technology; high purity H2 and CH4; advanced reforming; high temperature CO2 sorption; industrial CCS

Special Issue Information

Dear Colleagues,

Steam reforming is the most mature and economical technology used in the production of hydrogen and uses hydrocarbons reaction with steam to generate a H2 rich stream. It has been successfully deployed in industry using natural gas or naphtha as the feedstocks for many years. For its main reaction of methane with steam, producing CO and H2 as the main products, but also CO2 from water gas shift side reaction, the process relies on packed bed catalytic reactor technology, operated at medium high pressures (30-40 bar) and temperatures in the 850-1000 °C range. The reaction is strongly equilibrium driven, and pressures above atmospheric, whilst allowing reasonably sized plants delivering large throughputs, are adverse to the conversion of the hydrocarbon fuel. Steam to carbon ratios in the reformer are also carefully chosen to avoid coking in the reactor, which would poison the catalyst. Excess of steam and endothermicity of the steam reforming reaction make this process very energy intensive. Motivated by the need to reduce carbon emissions associated with H2 production, advanced steam reforming processes have now reached various stages of technology readiness level.

This special issue of Catalysts focusses on advances in steam reforming processes with equilibrium shift enhancing features brought about by in-situ product separation. The in-situ separation process effected by the presence of a sorbent or membrane or other, and require close coupling of catalyst and separation materials, and have resulted in novel materials and reactor designs a the steam reforming and at the water gas shift stage as well as widening the range of feedstocks suitable for steam reforming including renewable fuels with coking tendencies.

Dr. Valerie Dupont
Guest Editor

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Keywords

  • H2 production
  • steam reforming
  • water gas shift
  • sorption enhancement
  • membrane enhancement
  • equilibrium shift
  • hybrid catalysts
  • reactive membranes
  • in situ separation
  • unconventional gas
  • bio-compounds
  • process intensification

Published Papers (6 papers)

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Research

Open AccessArticle Steam Reforming of Methanol over Nanostructured Pt/TiO2 and Pt/CeO2 Catalysts for Fuel Cell Applications
Catalysts 2018, 8(11), 544; https://doi.org/10.3390/catal8110544
Received: 30 October 2018 / Revised: 9 November 2018 / Accepted: 10 November 2018 / Published: 15 November 2018
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Abstract
A research and technological challenge for fuel processors integrated with High Temperature Polymer Electrolyte Membrane Fuel Cells (HT-PEMFCs), also known as Internal Reforming Methanol Fuel Cells (IRMFCs), operating at 200–220 °C, is the development of highly efficient catalysts, which will be able to
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A research and technological challenge for fuel processors integrated with High Temperature Polymer Electrolyte Membrane Fuel Cells (HT-PEMFCs), also known as Internal Reforming Methanol Fuel Cells (IRMFCs), operating at 200–220 °C, is the development of highly efficient catalysts, which will be able to selectively (low CO and other by-products formation) produce the required quantity of hydrogen at these temperatures. In this work, various amounts of platinum were dispersed via deposition-precipitation (DP) and impregnation (I) methods onto the surface of hydrothermally prepared ceria nanorods (CNRs) and titania nanotubes (TNTs). These nanostructured catalysts were evaluated in steam reforming of methanol process targeting the operation level of IRMFCs. The (DP) method resulted in highly (atomically) dispersed platinum-based catalysts, as confirmed with Scanning Transmission Electron Microscopy (STEM) analysis, with a mean particle size of less than 1 nm in the case of 0.35 wt.% Pt/CNRs catalyst. Ultra-fine dispersion of platinum species correlated with the presence of oxygen vacancies, together with the enrichment of CNRs surface with active metallic phase resulted in a highly active catalyst achieving at 220 °C a hydrogen production rate of 5500 cm3 min−1 per g of loaded platinum. Full article
(This article belongs to the Special Issue Catalysis in Steam Reforming)
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Open AccessArticle High Active and Selective Ni/CeO2–Al2O3 and Pd–Ni/CeO2–Al2O3 Catalysts for Oxy-Steam Reforming of Methanol
Catalysts 2018, 8(9), 380; https://doi.org/10.3390/catal8090380
Received: 2 August 2018 / Revised: 27 August 2018 / Accepted: 2 September 2018 / Published: 6 September 2018
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Abstract
Herein, we report monometallic Ni and bimetallic Pd–Ni catalysts supported on CeO2–Al2O3 binary oxide which are highly active and selective in oxy-steam reforming of methanol (OSRM). Monometallic and bimetallic supported catalysts were prepared by an impregnation method. The
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Herein, we report monometallic Ni and bimetallic Pd–Ni catalysts supported on CeO2–Al2O3 binary oxide which are highly active and selective in oxy-steam reforming of methanol (OSRM). Monometallic and bimetallic supported catalysts were prepared by an impregnation method. The physicochemical properties of the catalytic systems were investigated using a range of methods such as: Brunauer–Emmett–Teller (BET), X-ray Powder Diffraction (XRD), Temperature-programmed reduction (TPR–H2), Temperature-programmed desorption (TPD–NH3), X-ray photoelectron spectroscopy (XPS) and Scanning Electron Microscope equipped with an energy dispersive spectrometer (SEM–EDS). We demonstrate that the addition of palladium facilitates the reduction of nickel catalysts. The activity tests performed for all catalysts confirmed the promotion effect of palladium on the catalytic activity of nickel catalyst and their selectivity towards hydrogen production. Both nickel and bimetallic palladium–nickel supported catalysts showed excellent stability during the reaction. The reported catalytic systems are valuable to make advances in the field of fuel cell technology. Full article
(This article belongs to the Special Issue Catalysis in Steam Reforming)
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Open AccessArticle Oxidative Steam Reforming of Raw Bio-Oil over Supported and Bulk Ni Catalysts for Hydrogen Production
Catalysts 2018, 8(8), 322; https://doi.org/10.3390/catal8080322
Received: 25 July 2018 / Revised: 5 August 2018 / Accepted: 6 August 2018 / Published: 8 August 2018
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Abstract
Several Ni catalysts of supported (on La2O3-αAl2O3, CeO2, and CeO2-ZrO2) or bulk types (Ni-La perovskites and NiAl2O4 spinel) have been tested in the oxidative steam reforming
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Several Ni catalysts of supported (on La2O3-αAl2O3, CeO2, and CeO2-ZrO2) or bulk types (Ni-La perovskites and NiAl2O4 spinel) have been tested in the oxidative steam reforming (OSR) of raw bio-oil, and special attention has been paid to the catalysts’ regenerability by means of studies on reaction-regeneration cycles. The experimental set-up consists of two units in series, for the separation of pyrolytic lignin in the first step (at 500 °C) and the on line OSR of the remaining oxygenates in a fluidized bed reactor at 700 °C. The spent catalysts have been characterized by N2 adsorption-desorption, X-ray diffraction and temperature programmed reduction, and temperature programmed oxidation (TPO). The results reveal that among the supported catalysts, the best balance between activity-H2 selectivity-stability corresponds to Ni/La2O3-αAl2O3, due to its smaller Ni0 particle size. Additionally, it is more selective to H2 than perovskite catalysts and more stable than both perovskites and the spinel catalyst. However, the activity of the bulk NiAl2O4 spinel catalyst can be completely recovered after regeneration by coke combustion at 850 °C because the spinel structure is completely recovered, which facilitates the dispersion of Ni in the reduction step prior to reaction. Consequently, this catalyst is suitable for the OSR at a higher scale in reaction-regeneration cycles. Full article
(This article belongs to the Special Issue Catalysis in Steam Reforming)
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Open AccessArticle Investigation of Ni/SiO2 Fiber Catalysts Prepared by Different Methods on Hydrogen production from Ethanol Steam Reforming
Catalysts 2018, 8(8), 319; https://doi.org/10.3390/catal8080319
Received: 12 July 2018 / Revised: 31 July 2018 / Accepted: 2 August 2018 / Published: 4 August 2018
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Abstract
Ni/SiO2 (Ni/SF) catalysts were prepared by electrospinning of the SF followed by impregnation. The performance of the Ni/SF catalysts for hydrogen production from ethanol steam reforming at various conditions was investigated in comparison with a conventional Ni/silica porous (Ni/SP) catalyst. The influence
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Ni/SiO2 (Ni/SF) catalysts were prepared by electrospinning of the SF followed by impregnation. The performance of the Ni/SF catalysts for hydrogen production from ethanol steam reforming at various conditions was investigated in comparison with a conventional Ni/silica porous (Ni/SP) catalyst. The influence of the Ni/SF catalyst preparation methods on the catalytic activity and stability in ethanol steam reforming was also studied. The catalysts were prepared by three different preparation techniques: impregnation (IM), deposition precipitation (DP) and strong electrostatic adsorption (SEA). The Ni/SF catalyst exhibited higher performances and stability than the Ni/SP catalyst. The H2 yields of 55% and 47% were achieved at 600 °C using the Ni/SF and Ni/SP catalysts, respectively. The preparation methods had a significant effect on the catalytic activity and stability of the Ni/SF catalyst, where that prepared by the SEA method had a smaller Ni particle size and higher dispersion, and also exhibited the highest catalytic activity and stability compared to the Ni/SF catalysts prepared by IM and DP methods. The maximum H2 yield produced from the catalyst prepared by SEA was 65%, while that from the catalysts prepared by DP and IM were 60% and 55%, respectively, under the same conditions. The activity of the fiber catalysts prepared by SEA, DP and IM remained almost constant at all times during a 16 h stability test. Full article
(This article belongs to the Special Issue Catalysis in Steam Reforming)
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Open AccessArticle Hydrogen-Etched TiO2−x as Efficient Support of Gold Catalysts for Water–Gas Shift Reaction
Catalysts 2018, 8(1), 26; https://doi.org/10.3390/catal8010026
Received: 30 December 2017 / Revised: 8 January 2018 / Accepted: 9 January 2018 / Published: 15 January 2018
Cited by 3 | PDF Full-text (11584 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Hydrogen-etching technology was used to prepare TiO2−x nanoribbons with abundant stable surface oxygen vacancies. Compared with traditional Au-TiO2, gold supported on hydrogen-etched TiO2−x nanoribbons had been proven to be efficient and stable water–gas shift (WGS) catalysts. The
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Hydrogen-etching technology was used to prepare TiO2−x nanoribbons with abundant stable surface oxygen vacancies. Compared with traditional Au-TiO2, gold supported on hydrogen-etched TiO2−x nanoribbons had been proven to be efficient and stable water–gas shift (WGS) catalysts. The disorder layer and abundant stable surface oxygen vacancies of hydrogen-etched TiO2−x nanoribbons lead to higher microstrain and more metallic Au0 species, respectively, which all facilitate the improvement of WGS catalytic activities. Furthermore, we successfully correlated the WGS thermocatalytic activities with their optoelectronic properties, and then tried to understand WGS pathways from the view of electron flow process. Hereinto, the narrowed forbidden band gap leads to the decreased Ohmic barrier, which enhances the transmission efficiency of “hot-electron flow”. Meanwhile, the abundant surface oxygen vacancies are considered as electron traps, thus promoting the flow of “hot-electron” and reduction reaction of H2O. As a result, the WGS catalytic activity was enhanced. The concept involved hydrogen-etching technology leading to abundant surface oxygen vacancies can be attempted on other supported catalysts for WGS reaction or other thermocatalytic reactions. Full article
(This article belongs to the Special Issue Catalysis in Steam Reforming)
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Open AccessArticle Bio-Oil Steam Reforming over a Mining Residue Functionalized with Ni as Catalyst: Ni-UGSO
Catalysts 2018, 8(1), 1; https://doi.org/10.3390/catal8010001
Received: 17 November 2017 / Revised: 12 December 2017 / Accepted: 15 December 2017 / Published: 22 December 2017
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Abstract
Bio-oil reforming is considered for syngas or H2 production. In this work, we studied the steam reforming (SR) of two raw bio-oils without adding external steam, using a recently-developed catalyst, Ni-UGSO. Experiments were performed at temperature (T) = 750–850 °C
[...] Read more.
Bio-oil reforming is considered for syngas or H2 production. In this work, we studied the steam reforming (SR) of two raw bio-oils without adding external steam, using a recently-developed catalyst, Ni-UGSO. Experiments were performed at temperature (T) = 750–850 °C and weight hourly space velocity (WHSV) = 1.7–7.1 g/gcat/h to assess C conversion (XC) and product yields. The results show that, in all conditions and with both bio-oils tested, the catalyst is stable for the entire duration of the tests (~500 min) even when some C deposition occurred and that only at the highest WHSV tested there is a slight deactivation. In all tests, catalytic activity remained constant after a first, short, transient state, which corresponded to catalyst activation. The highest yields and conversions, with Y H 2 , Y CO and XC of 94%, 84% and 100%, respectively, were observed at temperatures above 800 °C and WHSV = 1.7 g/gcat/h. The amount of H2O in the bio-oils had a non-negligible effect on catalyst activity, impacting Y H 2 , Y CO and XC values. It was observed that, above a critical amount of H2O, the catalyst was not fully activated. However, higher H2O content led to the reduction of C deposits as well as lower Y H 2 and Y CO and, through the water-gas-shift reaction, to higher Y CO 2 (CO2 selectivity). Fresh and spent catalysts were analyzed by physisorption (BET), X-ray diffraction, scanning electron microscopy and thermogravimetric analysis: the results reveal that, during the oils’ SR reaction, the initial spinel (Ni-Fe-Mg-Al) structures decreased over time-on-stream (TOS), while metallic Ni, Fe and their alloy phases appeared. Although significant sintering was observed in used catalysts, especially at high H2O/C ratio, the catalyst’s specific surface generally increased; the latter was attributed to the presence of nanometric metallic Ni and Ni-Fe alloy particles formed by reduction reactions. A small amount of C (4%) was formed at low H2O/C. Full article
(This article belongs to the Special Issue Catalysis in Steam Reforming)
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