The Role of Cu(I) Species for Photocatalytic Hydrogen Generation Over CuO x /TiO2

Abstract

The fabrication of different CuO x species (Cu(0), Cu(I) and Cu(II) species) over TiO 2 has been accomplished and their roles in photoinduced hydrogen generation have been investigated. The results indicate that the positive charge in CuO x center affect photo-induced charge transfer significantly. Cu(I) species seems promote photocurrent generation while the Cu(II) species inhibits the photocurrent generation. Photoactivity order follows the similar sequence. Lower temperature calcination helps the formation of Cu(I) species and higher temperature treatment leads to the formation of Cu(II) species. At the lower loading level, the Cu content increase leads to the activity increase, but over loading of copper resulted in the decrease of activities for hydrogen generation. Detail analysis indicates that too much copper loading induces more Cu(II) center formation, as a results, the activity for hydrogen generation decreases. The species of Cu(0) does no affect the activity obviously at low loading level and shows detrimental effect at high loading level. The optimal loading amount of copper is 1.0Cu (wt%).

Hydrogen Production by Photoreforming of Renewable Substrates

“…Cu x O-TiO 2 (x = 1, 2) nanocomposites were tested for ethanol PR [180,181]. The best performance was achieved with 1 wt% metal loading, due to the main presence of Cu(I) ions, active sites for the transfer of photogenerated electrons, whereas Cu(II) species seem to promote electron-hole recombination.…”

Efficient approach for simultaneous CO and H2 production via photoreduction of CO2 with water over copper nanoparticles loaded TiO2

“…Due to the low cost and availability, copper would be a better choice to modify TiO 2 . Many researchers had reported copper modified TiO 2 catalysts for enhanced photocatalytic activities and also photocatalytic reduction of CO 2 [15][16][17][18][19]. Liu et al have synthesized copper-loaded titania photocatalysts in one pot reaction and observed enhancement in CO 2 reduction to CO than with pure TiO 2 [20].…”

Loading Effect in Copper(II) Oxide Cluster-Surface-Modified Titanium(IV) Oxide on Visible- and UV-Light Activities

“…[17][18][19][20][21][22][23][24] Among them, Cu 2+ ion and CuO have attracted much interest as a promising surface modifier. [25][26][27][28][29][30][31][32] Interestingly, Irie et al have shown that Cu 2+ -grafted TiO 2 (Cu 2+ /TiO 2 ) prepared by the impregnation method has oxidation ability sufficient for completely decomposing 2-propanol under visible-light irradiation. 28 Even if visible-light activity appears, it is usually much smaller than UV-light activity, and thus, the compatibility of high visible and UVlight activities is important from a viewpoint of effective sunlight use.…”