Browsing Institutt for kjemisk prosessteknologi by Author "Walmsley, John"

Now showing items 1-13 of 13

    • Active sites for the oxygen reduction reaction in nitrogen-doped carbon nanofibers 

      Buan, Marthe Emelie Melandsø; Cognigni, Andrea; Walmsley, John; Muthuswamy, Navaneethan; Rønning, Magnus (Journal article; Peer reviewed, 2019)
      Understanding the role of iron and the nature of the active sites in nitrogen-doped carbon nanomaterials is vital for their future application as oxygen reduction electrocatalysts in fuel cells. In this paper, porphyrin-like ...

    • Decoding atomic-level structures of the interface between Pt sub-nanocrystals and nanostructured carbon 

      Cheng, Hongye; Kvande, Ingvar; Zhu, Yi-An; Hammer, Nina; Rønning, Magnus; Walmsley, John; Li, Ping; Qi, Zhiwen; Zhou, Xing-Gui; Chen, De (Journal article; Peer reviewed, 2018)
      Gaining an insight into the interface structure resulting from the interaction between metal nanoparticles and their supports, particularly under relevant reaction conditions, has been an important topic in heterogeneous ...

    • Effects of metal dusting relevant exposures of alloy 601 surfaces on carbon formation and oxide development 

      Guo, Xiaoyang; Vanhaecke, Estelle Marie M.; Vullum, Per Erik; Ma, Jianyu; Panditha Vidana, Daham Sanjaya Gunawardana; Walmsley, John; Chen, De; Venvik, Hilde Johnsen (Peer reviewed; Journal article, 2020)
      Ni and Fe are excellent catalysts for carbon formation, and industrial alloys are therefore susceptible to metal dusting corrosion; a costly issue in e.g. synthesis gas manufacture. The objective of this work is to better ...

    • Effects of sulphur on a Co/Mn-based catalyst for Fischer-Tropsch reactions 

      Enger, Bjørn Christian; Walmsley, John; Svenum, Ingeborg-Helene; Tolchard, Julian R; Yang, Jia; Myrstad, Rune; Gjervan, Torbjørn; Khan, Asad Ahmad; Mutairi-Al, Abdulkarim; Karim, Khalid (Journal article; Peer reviewed, 2018)
      The long term effect of up to 10 ppm H2S was studied for Fischer–Tropsch conversion of syngas by catalytic testing at 240 °C, 5 bar, H2/CO = 2.1 and GHSV = 2400 Nml/gcat h. Sulphur was dosed after ~ 300 or ~ 1000 h time ...

    • Evaluation of ORR active sites in nitrogen-doped carbon nanofibers by KOH post treatment 

      Muthuswamy, Navaneethan; Buan, Marthe Emelie Melandsø; Walmsley, John; Rønning, Magnus (Journal article; Peer reviewed, 2018)
      Oxygen reduction on N-doped carbon nanomaterials is believed to take place at either N-centered active sites (C-Nx) or Fe-centered active sites (Fe-Nx). In this work the origin of the oxygen reduction on nitrogen-doped ...

    • Evaluation of Reoxidation Thresholds for γ-Al2O3-Supported Cobalt Catalysts under Fischer - Tropsch Synthesis Conditions 

      Tsakoumis, Nikolaos; Walmsley, John; Rønning, Magnus; van Beek, Wouter; Rytter, Erling; Holmen, Anders (Journal article; Peer reviewed, 2017)
      Size-dependent phenomena at the nanoscale influence many applications, notably in the science of heterogeneous catalysis. In cobalt-based Fischer–Tropsch synthesis (FTS), the size of Co nanoparticles (NPs) dictates to a ...

    • Investigation of metal dusting corrosion process over UNS N08800 alloy 

      Guo, Xiaoyang; Panditha Vidana, Daham Sanjaya Gunawardana; Chen, De; Vanhaecke, Estelle Marie M.; Venvik, Hilde Johnsen; Walmsley, John (Journal article; Peer reviewed, 2017)
      Metal dusting corrosion is a catastrophic degradation phenomenon that initiates on metallic surfaces of chemical process equipment at elevated temperature and under carburizing atmospheres. It proceeds by a gradual breakdown ...

    • Methane activation on bimetallic catalysts: properties and functions of surface Ni-Ag alloy 

      Dam, Anh Hoang; Wang, Hongmin; Dehghan-Niri, Roya; Yu, Xiaofeng; Walmsley, John; Holmen, Anders; Yang, Jia; Chen, De (Peer reviewed; Journal article, 2019)
      The paper presents a fundamental study of the properties and functions of well‐defined Ni−Ag surface alloys in methane decomposition and steam reforming, aiming at providing a better understanding of the principle for ...

    • Nanostructural Analysis of Co-Re/γ-Al2O3 Fischer-Tropsch Catalyst by TEM and XRD 

      Dehghan-Niri, Roya; Tsakoumis, Nikolaos E.; Voronov, Alexey; Holmen, Anders; Holmestad, Randi; Vullum, Per Erik; Borg, Øyvind; Rytter, Erling; Rønning, Magnus; Walmsley, John (Journal article; Peer reviewed, 2022)
      A rhenium promoted Fischer-Tropsch (FT) cobalt catalyst supported on γ-Al2O3 has been investigated by Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD), before and after reduction. Electron diffraction, ...

    • Nitrogen-doped Carbon Nanofibers for the Oxygen Reduction Reaction: Importance of the Iron Growth Catalyst Phase 

      Buan, Marthe Emelie Melandsø; Muthuswamy, Navaneethan; Walmsley, John; Chen, De; Rønning, Magnus (Journal article; Peer reviewed, 2017)
      A systematic evaluation of the oxygen reduction reaction (ORR) on nitrogen-doped carbon nanofibers (N-CNFs) has been performed by tuning the properties of the N-CNFs by using chemical vapor deposition. Analysis of the ...

    • Nitrogen-doped carbon nanofibers on expanded graphite as oxygen reduction electrocatalysts 

      Buan, Marthe Emelie Melandsø; Muthuswamy, Navaneethan; Walmsley, John; Chen, De; Rønning, Magnus (Journal article; Peer reviewed, 2016)
      A single-step chemical vapor deposition method using simple gaseous precursors was employed to grow nitrogen-doped carbon nanofibers from Fe and Ni particles on the surface of expanded graphite (N-CNF/EG). Due to the high ...

    • X-ray absorption, X-ray diffraction and electron microscopy study of spent cobalt based catalyst in semi-commercial scale Fischer-Tropsch synthesis 

      Tsakoumis, Nikolaos; Dehghan-Niri, Roya; Rønning, Magnus; Walmsley, John; Borg, Øyvind; Rytter, Erling; Holmen, Anders (Peer reviewed; Journal article, 2014)
      Calcined, reduced and spent Co-Re/γ-Al2O3 catalysts for Fischer–Tropsch synthesis (FTS) were characterized and compared. Co-K-edge and Re-LIII-edge X-ray absorption near edge structure (XANES), X-ray powder diffraction ...

    • ZnO-Carbon-Nanotube Composite Supported Nickel Catalysts for Selective Conversion of Cellulose into Vicinal Diols 

      Van der Wijst, Cornelis; Duan, Xuezhi; Liland, Ingvild Skeie; Walmsley, John; Zhu, Jun; Wang, Aiqin; Zhang, Tao; Chen, De (Journal article; Peer reviewed, 2015)
      A ZnO-nanolayer-coated carbon nanotube (CNT) composite (ZnO–CNT) was employed as a support to immobilise Ni catalysts. Well-mixed oxides, formed as a result of enhanced interfaces between the two oxides on CNTs, resulted ...