catalysts Article VAlPOs as Efficient Catalysts for Glycerol Conversion to Methanol 1, , 2, 2 2 Gheorghit, a Mitran * y, Florentina Neat, u y,S, tefan Neat, u , Mihaela M. Trandafir and Mihaela Florea 1,2,* 1 Department of Organic Chemistry, University of Bucharest, Biochemistry & Catalysis, Faculty of Chemistry, 4-12, Blv. Regina Elisabeta, 030018 Bucharest, Romania 2 National Institute of Material Physics, 405A Atomi¸stilor, P.O. Box MG 7, 077125 Măgurele, Romania; florentina.neatu@infim.ro (F.N.); stefan.neatu@infim.ro (S, .N.); mihaela.trandafir@infim.ro (M.M.T.) * Correspondence:
[email protected] (G.M.); mihaela.florea@infim.ro (M.F.) Authors with equal contribution. y Received: 24 April 2020; Accepted: 28 June 2020; Published: 1 July 2020 Abstract: The catalytic activity of a series of vanadium aluminophosphates catalysts prepared by sol-gel method followed by combustion of the obtained gel was evaluated in glycerol conversion towards methanol. The materials were characterized by several techniques such as X-ray diffraction (XRD), UV-vis, Fourier-transform infrared (FTIR), Raman and X-ray photoelectron (XPS) spectroscopies. The amount of vanadium incorporated in aluminophosphates framework played an important role in the catalytic activity, while in the products distribution the key role is played by the vanadium oxidation state on the surface. The sample that contains a large amount of V4+ has the highest selectivity towards methanol. On the sample with the lowest vanadium loading the oxidation path to dihydroxyacetone is predominant. The catalyst with higher content of tetrahedral isolated vanadium species, such V5APO, is less active in breaking the C–C bonds in the glycerol molecule than the one containing polymeric species.