Hydrogen, the cleanest and most promising energy vector, can be produced by solar into chemical energy conversion, either by the photocatalytic direct splitting of water into Hand O, or, more efficiently,in the presen...Hydrogen, the cleanest and most promising energy vector, can be produced by solar into chemical energy conversion, either by the photocatalytic direct splitting of water into Hand O, or, more efficiently,in the presence of sacrificial reagents, e.g., in the so-called photoreforming of organics. Efficient photocatalytic materials should not only be able to exploit solar radiation to produce electron–hole pairs, but also ensure enough charge separation to allow electron transfer reactions, leading to solar energy driven thermodynamically up-hill processes. Recent achievements of our research group in the development and testing of innovative TiO-based photocatalytic materials are presented here, together with an overview on the mechanistic aspects of water photosplitting and photoreforming of organics. Photocatalytic materials were either（i） obtained by surface modification of commercial photocatalysts, or produced（ii） in powder form by different techniques, including traditional sol gel synthesis, aiming at engineering their electronic structure, and flame spray pyrolysis starting from organic solutions of the precursors, or（iii） in integrated form, to produce photoelectrodes within devices, by radio frequency magnetron sputtering or by electrochemical growth of nanotube architectures, or photocatalytic membranes, by supersonic cluster beam deposition.展开更多
The two-phase volume-averaged model with the detailed chemistry reaction mechanism GRI 3.0 was adopted in the quasi-steady-state simulation of hydrogen production by CH4-rich filtration combustion in an alumina foam u...The two-phase volume-averaged model with the detailed chemistry reaction mechanism GRI 3.0 was adopted in the quasi-steady-state simulation of hydrogen production by CH4-rich filtration combustion in an alumina foam under fully developed conditions. The relations among the combustion wave velocity, the inlet gas velocity and the equivalence ratio were discussed, and their influences on the distributions of temperature and species in the alumina foam and on H2 yield, CH4 conversion, H2 selectivity and CO selectivity were analyzed in detail. The results show that the combustion wave velocity increases with the increase of equivalence ratio or inlet gas velocity. The H2 yield exceeded 50% with equivalence ratio between 2.0 and 3.0 and combustion wave velocity larger than 0.4 mm/s. The H2 selectivity exceeded 50% with equivalence ratio larger than 2.0 and CO selectivity exceeded 80% with equivalence ratio between 1.8 and 2.0 and combustion wave velocity larger than 0.4 mm/s.展开更多
基金supported by Fondazione Cariplo through Grants 2009-2477 and 2013-0615
文摘Hydrogen, the cleanest and most promising energy vector, can be produced by solar into chemical energy conversion, either by the photocatalytic direct splitting of water into Hand O, or, more efficiently,in the presence of sacrificial reagents, e.g., in the so-called photoreforming of organics. Efficient photocatalytic materials should not only be able to exploit solar radiation to produce electron–hole pairs, but also ensure enough charge separation to allow electron transfer reactions, leading to solar energy driven thermodynamically up-hill processes. Recent achievements of our research group in the development and testing of innovative TiO-based photocatalytic materials are presented here, together with an overview on the mechanistic aspects of water photosplitting and photoreforming of organics. Photocatalytic materials were either（i） obtained by surface modification of commercial photocatalysts, or produced（ii） in powder form by different techniques, including traditional sol gel synthesis, aiming at engineering their electronic structure, and flame spray pyrolysis starting from organic solutions of the precursors, or（iii） in integrated form, to produce photoelectrodes within devices, by radio frequency magnetron sputtering or by electrochemical growth of nanotube architectures, or photocatalytic membranes, by supersonic cluster beam deposition.
基金Supported by the China Postdoctoral Science Foundation (Grant No. 20080440713)the National Hi-Tech Research and Development Program ("863" Project) (Grant Nos. 2007AA05Z105, 2007AA05Z236)the National Natural Science Foundation of China (Grant No. 50776036)
文摘The two-phase volume-averaged model with the detailed chemistry reaction mechanism GRI 3.0 was adopted in the quasi-steady-state simulation of hydrogen production by CH4-rich filtration combustion in an alumina foam under fully developed conditions. The relations among the combustion wave velocity, the inlet gas velocity and the equivalence ratio were discussed, and their influences on the distributions of temperature and species in the alumina foam and on H2 yield, CH4 conversion, H2 selectivity and CO selectivity were analyzed in detail. The results show that the combustion wave velocity increases with the increase of equivalence ratio or inlet gas velocity. The H2 yield exceeded 50% with equivalence ratio between 2.0 and 3.0 and combustion wave velocity larger than 0.4 mm/s. The H2 selectivity exceeded 50% with equivalence ratio larger than 2.0 and CO selectivity exceeded 80% with equivalence ratio between 1.8 and 2.0 and combustion wave velocity larger than 0.4 mm/s.
