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Direct Synthesis of Hydrogen and Dimethoxylmethane from Methanol on Copper/Silica Catalysts with Optimal Cu + /Cu 0 Sites
Author(s) -
Wu Liubi,
Li Bolong,
Zhao Chen
Publication year - 2018
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201701416
Subject(s) - dehydrogenation , methanol , catalysis , hydrogen , chemistry , inorganic chemistry , hydrogen production , copper , formaldehyde , supercritical fluid , organic chemistry
Abstract Hydrogen is an important sustainable resource, and here we report a catalytic route for the direct production of hydrogen (with a purity of 95 %) and dimethoxylmethane (DMM) from supercritical methanol over a Cu/SiO 2 catalyst prepared by deposition–precipitation with ammonia (DPA) at 240°C in a one‐pot process. The procedure starts with methanol dehydrogenation to hydrogen and formaldehyde at the interface of the Cu 2 O⋅SiO 2 –Cu 0 particle mixture, and subsequently, the formaldehyde intermediate condenses with substantial methanol to form DMM in the liquid phase. The Cu 0 , CuO, and chrysocolla species are inactive for hydrogen generation from methanol, and the intrinsic active species for methanol decomposition is the Cu 2 O⋅SiO 2 –Cu 0 nanoparticle interface, which is produced from the hydrogen reduction of Cu 2 Si 2 O 5 (OH) 2 or from the methanol reduction of Cu−O−Si moieties. A correlation between the structure and activity on reduced Cu/SiO 2 (DPA) suggested that only Cu 0 was not active, but the combined Cu 0 and Cu + sites with interfaces on SiO 2 with an optimal Cu + /Cu 0 ratio of 1.56 were highly active for methanol dehydrogenation and subsequent condensation steps. The developed new catalytic system offers a facile and atom‐economical way to generate pure hydrogen (almost CO free) from liquid methanol that can be used in fuel cell and hydrogen‐involved biomass reactions.