Electrocatalytic Conversion of Glucose into Hydrogen and Value-Added Compounds on Gold and Nickel Catalysts

Abstract

Fine chemistry historically relies on the fossil fuel industry, implying oil extraction and refining [1]. The rarefaction of this resource and adverse environmental consequences of its extraction motivate research for alternative sources of chemicals. Low carbon footprint chemicals can be synthesized from nonedible biomass waste [2]; cellulose extracted from biomass can therefore play an important role, being a clean and widely accessible carbon source. One can extract D-Glucose (units that constitute cellulose) from cellulose and obtain numerous chemicals of interest, such as sorbitol [3][4] or gluconic acid [5][6] (gluconate in alkaline media), respectively by selective reduction or oxidation.Searching for high-performance non-enzymatic catalysts to perform such reactions brought us to study the activity and selectivity of gold and nickel in alkaline media. At the anode, results from differential electrochemical mass spectrometry (DEMS) seem to indicate that the glucose oxidation on a gold surface initiates by its dissociative adsorption (dehydrogenation): the dihydrogen (H2) produced likely originates from the formation of metastable H adsorbates (Had) [7] that diffuse onto the surface [8] and recombine into H2. In parallel, the adsorbed glucose oxidizes into value-added products such as gluconic acid, through a mechanism proposed from in situ (Fourier Transform InfraRed spectroscopy, FTIR) and ex situ (products analysis by High Performance Liquid Chromatography, HPLC) observations, and on the evaluation of the number of exchanged electrons using the rotating ring disk electrode (RRDE). Confronting the experimental data to a microkinetics model enables to validate the proposed mechanism and to estimate the kinetics rate constants. At the cathode, the glucose reduction reaction (GRR) into sorbitol competes with the hydrogen evolution reaction (HER). The HER activity of nickel strongly depends on its surface oxidation state [9], which can be tuned to search the best selectivity towards sorbitol. Combining high value-added compounds production with H2 as by-product allows to improve the overall energy efficiency of this electrolysis.[1] P. G. Levi and J. M. Cullen, “Mapping global flows of chemicals: from fossil fuel feedstocks to chemical products,” Environ. Sci. Technol., vol. 52, no. 4, pp. 1725–1734, 2018, doi: 10.1021/acs.est.7b04573.[2] D. Saygin, D. J. Gielen, M. Draeck, E. Worrell, and M. K. Patel, “Assessment of the technical and economic potentials of biomass use for the production of steam, chemicals and polymers,” Renew. Sustain. Energy Rev., vol. 40, pp. 1153–1167, 2014, doi: 10.1016/j.rser.2014.07.114.[3] B. García, J. Moreno, G. Morales, J. A. Melero, and J. Iglesias, “Production of sorbitol via catalytic transfer hydrogenation of glucose,” Appl. Sci., vol. 10, no. 5, 2020, doi: 10.3390/app10051843.[4] X. Guo et al., “Selective hydrogenation of D-glucose to D-sorbitol over Ru/ZSM-5 catalysts,” Chinese J. Catal., vol. 35, no. 5, pp. 733–740, May 2014, doi: 10.1016/S1872-2067(14)60077-2.[5] H. S. Isbell, H. L. Frush, and F. J. Bates, “Manufacture of calcium gluconate by electrolytic oxidation of dextrose,” Ind. Eng. Chem., vol. 24, no. 4, pp. 375–378, 1932, doi: 10.1021/ie50268a003.[6] S. Anastassiadis and I. Morgunov, “Gluconic acid production,” Recent Pat. Biotechnol., vol. 1, no. 2, pp. 167–180, May 2007, doi: 10.2174/187220807780809472.[7] M. M. Jaksic, B. Johansen, and R. Tunold, “Electrochemical behaviour of gold in acidic and alkaline solutions of heavy and regular water,” Int. J. Hydrogen Energy, vol. 18, no. 2, pp. 91–110, Feb. 1993, doi: 10.1016/0360-3199(93)90196-H.[8] J. Cornejo-Romero, A. Solis-Garcia, S. M. Vega-Diaz, and J. C. Fierro-Gonzalez, “Reverse hydrogen spillover during ethanol dehydrogenation on TiO2-supported gold catalysts,” Mol. Catal., vol. 433, pp. 391–402, 2017, doi: 10.1016/j.mcat.2017.02.041.[9] A. G. Oshchepkov et al., “Nanostructured nickel nanoparticles supported on vulcan carbon as a highly active catalyst for the hydrogen oxidation reaction in alkaline media,” J. Power Sources, vol. 402, no. June, pp. 447–452, 2018, doi: 10.1016/j.jpowsour.2018.09.051. Figure 1