Electrocatalytic Hydrogenation and Deoxygenation of Glucose on Solid Metal Electrodes

Authors

  • Youngkook Kwon,

    1. Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (The Netherlands), Fax: (+31) 071-527-4451
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  • Prof. Marc T. M. Koper

    Corresponding author
    1. Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (The Netherlands), Fax: (+31) 071-527-4451
    • Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA Leiden (The Netherlands), Fax: (+31) 071-527-4451
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Abstract

This Full Paper addresses the electrocatalytic hydrogenation of glucose to sorbitol or 2-deoxysorbitol on solid metal electrodes in neutral media. Combining voltammetry and online product analysis with high-performance liquid chromatography (HPLC), provides both qualitative and quantitative information regarding the reaction products as a function of potential. Three groups of catalysts clearly show affinities toward: (1) hydrogen formation [on early transition metals (Ti, V, Cr, Mn, Zr, Nb, Mo, Hf, Ta, We, and Re) and platinum group metals (Ru, Rh, Ir, and Pt)], (2) sorbitol formation [on late transition metals (Fe, Co, Ni, Cu, Pd, Au, and Ag) and Al (sp metal)], and (3) sorbitol and 2-deoxysorbitol formation [on post-transition metals (In, Sn, Sb, Pb, and Bi), as well as Zn and Cd (d metals)]. Ni shows the lowest overpotential for the onset of sorbitol formation (−0.25 V) whereas Pb generates sorbitol with the highest yield (<0.7 mM cm−2). Different from a smooth Pt electrode, a large-surface-area Pt/C electrode hydrogenates glucose to sorbitol from −0.21 V with relatively low current. This emphasizes the importance of the active sites and the surface area of the catalyst. The mechanism to form 2-deoxysorbitol from glucose and/or fructose is discussed according to the observed reaction products. The yield and selectivity of hydrogenated products are highly sensitive to the chemical nature and state of the catalyst surface.

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