Effects of sol–gel procedures on the photocatalysis of Cu/TiO2 in CO2 photoreduction

Understanding the Reaction Mechanism of Photocatalytic Reduction of CO2 with H2O on TiO2-Based Photocatalysts: A Review

“…Only one study in the literature (Hirano et al, 1992) indicated that metallic Cu deposited on TiO 2 enhanced the photoefficiency of CO 2 reduction, where Cu metal played the roles as an effective co-catalyst for the reduction of CO 2 and as a reducing species to react with the positive holes simultaneously. On the contrary, Tseng et al (2004) pointed out that the presence of Cu 0 on Cu/TiO 2 obtained by H 2 reduction decreased the production of methanol product from CO 2 .…”

“…TiO 2 anatase, rutile or anataserutile mixed phase (e.g., Degussa P25 with a composition of 75% anatase and 25% rutile) has been frequently studied in photocatalytic reduction of CO 2 , using either bare TiO 2 or with incorporation of metal, nonmetal or metal oxide species (Anpo et al, 1995;Tseng et al, 2004;Koci et al, 2009;Zhang et al, 2011;Wang et al, 2012a;Wang et al, 2012b). By contrast, the brookite phase or anatase-brookite mixed phase is much less studied as a photocatalyst for CO 2 photoreduction, probably due to the previous difficulty in synthesizing high quality brookite nanocrystallites.…”

“…Second, electron transfer could be promoted in the direction from TiO 2 CB to external trappers or carriers. The electron trappers can be noble metals (e.g., Pt, Pd, Au, Ag) (Sasirekha et al, 2006;Iizuka et al, 2011;Yui et al, 2011;An et al, 2012;Uner and Oymak, 2012;Wang et al, 2012b) or metal oxides (e.g., CuO, FeO x , CeO 2 ) (Tseng et al, 2004;Qin et al, 2011;Srinivas et al, 2011;Wang et al, 2011b;Truong et al, 2012;Zhao et al, 2012b), and the electron carriers are often carbon materials (e.g., graphene) (Liang et al, 2011(Liang et al, , 2012Tu et al, 2012). Third, the incorporation of TiO 2 with another semiconductor, i.e., photo-sensitizer (e.g., AgBr, CdSe, PbS) Asi et al, 2011;Wang et al, 2011a;An et al, 2012) or n-type semiconductor (e.g., ZnO) (Xi et al, 2011), promotes electron transfer between the CB of the second semiconductor and the CB of TiO 2 .…”

“…In order to overcome the above limitations, several approaches have been attempted to modify TiO 2 , including the incorporation of TiO 2 with noble metals (Koci et al, 2010;Li et al, 2012;Wang et al, 2012b) , metal oxides (Tseng et al, 2002(Tseng et al, , 2004Slamet et al, 2005;Li et al, 2010;Liu et al, 2013b), and nonmetals (Varghese et al, 2009;Li et al, 2012;Zhang et al, 2011;Zhang et al, 2012), the dispersion of TiO 2 on high surface area supports Srinivas et al, 2011;Wang et al, 2011b;Zhao et al, 2012b), and the control of TiO 2 with different morphologies and crystal phases (DeSario et al, 2011;Jiao et al, 2012a;Li et al, 2008b;Liu et al, 2012b).…”

Preparation of nano-Cu2O/TiO2 photocatalyst from waste printed circuit boards by electrokinetic process

“…Transition metal deposition is believed could increase photocatalytic activity of TiO 2 by avoiding electron-hole recombination [14][15][16]. As a transition metal deposited catalyst, Cu species/TiO 2 has been studied widely because it has been indicated that Cu species modification could improve the photocatalytic activity of TiO 2 effectively [17][18][19][20].…”