Generation of acidic sites in Al, Ga, In salts of molybdenum and tungsten Keggin-type heteropolyacids. DFT modeling and catalytic tests
•MePMo salts exhibit weak redox properties while MePW is not active in redox reaction.•Both types of salts MePW and MePMo are active in acidic reactions.•Acidic properties change in decreasing order HPW > GaPW > InPW > AlPW >>> HPMo > GaPMo > InPMo > AlPMo.•Theoretical predictions were confirmed by experimental results.
The catalytic properties, both redox and acidic, of 12-tungsto- and 12-molybdo-phosphoric Al3+, Ga3+, In3+ salts were studied. As a model reaction the gas phase ethanol conversion was used. On different sites (redox and acidic) various products are obtained (acetaldehyde and diethyl ether/ethylene respectively). Catalytic activity of MePW and MePMo salts was theoretically predicted, using both periodic and cluster models. Performed experiments confirm the theoretical prediction concerning the influence of addenda atoms (W and Mo) and various counter-cations (Al3+, Ga3+, In3+) on the catalytic properties of studied systems.
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Journal: Catalysis Today - Volume 257, Part 1, 15 November 2015, Pages 72–79