Contents lists available at ScienceDirect Applied Catalysis A, General journal homepage: www.elsevier.com/locate/apcata Decomposition of glucose with in situ deoxygenation in a low H 2 pressure environment – Part I: Monometallic catalysts Kyle A. Rogers a , Ying Zheng a,b, ⁎ a Department of Chemical Engineering, University of New Brunswick, 15 Dineen Drive, Fredericton, NB, E3B 5A3, Canada b School of Engineering, University of Edinburgh, Mayfield Road, Edinburgh, EH9 3DW, UK ARTICLE INFO Keywords: Deoxygenation Water-gas-shift Glucose Decomposition Monometallic catalysts ABSTRACT Glucose was decomposed at 350 °C within a dilute H 2 environment in the presence of monometallic, deox- ygenation catalysts to promote in situ deoxygenation. The catalysts, which were supported on SiO 2 , included Ni, Cu, Co, and Fe in concentrations of 0.5 wt% and 4 wt% as well as Re, Pt, and Pd in concentrations of 0.5 wt%. Furanic compounds were used to identify deoxygenation due to their unique structures which allow them to be readily identified and because of their well-established deoxygenation reaction pathways. The 4% Co catalyst was deemed most superior at in situ deoxygenation. Ni catalysts were competitive in deoxygenation and helped reduce solid residue most substantially. 0.5 wt% catalysts reduced solid content the most however higher con- centrations were needed for better in situ deoxygenation. 1. Introduction Recent advances in the past decade have seen the development of thermochemical processes and catalysts to produce biofuel from lig- nocellulosic material. The general process scheme has been to perform pyrolysis or liquefaction on lignocellulosic material to produce a crude bio-oil and then refine it using hydroprocessing technologies to perform deoxygenation and produce fuels that are compatible with petroleum- based fuels [1–7]. The challenge therein has been the reduction in hydrogen consumption. The requirement for hydrogen represents a sustainability issue as most of the world’s hydrogen production (> 95% in 2005) is from non-renewable sources such as methane reforming processes [8]. During the decomposition of lignocellulosic material CO 2 , CO, H 2 , H 2 O, and light hydrocarbons are readily formed [2]. Given the presence of H 2 , there is potential to use the product gas (upon separation if ne- cessary) for deoxygenation. In addition, the presence of CO, H 2 O, and light hydrocarbons represents a potential to improve H 2 concentrations by promoting water-gas-shift (WGS) and reforming reactions. However, the infrastructure required to perform WGS - on top of already needing additional infrastructure for deoxygenation – represents an additional challenge in terms of costs. In a review it was discussed that future work regarding deoxygenation focus on reducing H 2 consumption by fo- cusing on catalysts that promote both WGS and deoxygenation [5]. Ideally then, it would be beneficial to perform all three steps (decomposition, WGS, and deoxygenation) in one stage – a one pot reaction stage. Therein, lignocellulosic material would be decomposed producing oxygenated compounds ready for deoxygenation. WGS re- actions of the gas products would produce in situ H 2 which would then be used by a catalyst to perform selective deoxygenation. Widyawati et al. [9] investigated the potential of producing in situ H 2 during biomass pyrolysis using CaO to capture CO 2 thereby im- pacting the thermodynamics of the WGS reaction and producing more H 2 . They determined that promoting WGS with CaO allowed for sig- nificant increase in H 2 production during primary pyrolysis reactions. Kan et al. [10] studied the pyrolysis of coffee grounds using a NiCu catalyst and suggested that the presence of Cu promoted WGS during pyrolysis along with reforming. Supported metallic catalysts such as Ni and Pd catalysts have been investigated for tar-cracking/reforming activity during pyrolysis thus producing H 2 [11–15]. 5%Ni/MCM-41 for example was shown to increase the vol% of H 2 in the outlet gas from 1.2% (without catalyst) to 16.5% due to its activity towards tar- cracking [14]. In situ deoxygenation of lignocellulosic decomposition products is rarely studied. However, deoxygenation reaction pathways of in situ deoxygenation are expected to be consistent with the typical deox- ygenation reactions that are reported for bio-oil model compounds. Said model compounds have consisted of both phenolic (guaiacol) and furanic (furfural) compounds. Due to limits in hydrogen though, se- lective/direct deoxygenation reaction pathways would be ideal for https://doi.org/10.1016/j.apcata.2018.10.015 Received 23 July 2018; Received in revised form 11 October 2018; Accepted 15 October 2018 ⁎ Corresponding author at: School of Engineering, University of Edinburgh, Mayfield Road, Edinburgh, EH9 3DW, UK. E-mail address: y.zheng@ed.ac.uk (Y. Zheng). Applied Catalysis A, General 569 (2019) 75–85 Available online 18 October 2018 0926-860X/ © 2018 Elsevier B.V. All rights reserved. T