Efficiently enhancing the photocatalytic activity of faceted TiO₂nanocrystals by selectively loading α-Fe₂O₃and Pt co-catalysts

Abstract

The photocatalytic activity of faceted TiO2nanocrystals was efficiently enhanced by selectively loading α-Fe2O3and Pt co-catalysts onto specific facets.

Dual Cocatalysts in TiO2 Photocatalysis

“…Generally, most cocatalysts can serve as reduction cocatalysts for the photocatalytic hydrogen evolution and CO 2 reduction reactions, such as noble metals, non‐noble metals, metal oxides (e.g., CuO and NiO), metal hydroxides, metal sulfides, metal phosphides (e.g., Co 2 P and Ni 2 P) and carbonaceous materials. By contrast, some transition metal oxides (e.g., MnO x , CoO x , and Fe 2 O 3 ) and phosphide (e.g., Co–Pi) are used as oxidation cocatalysts for photocatalytic oxygen evolution reaction and photocatalytic degradation of pollutants.…”

“…Recently, several transition metal oxides, such as CoO x , MnO x , FeO x , RuO 2 , IrO x , CuO x , and NiO, have been developed as low‐cost and efficient cocatalysts for photocatalytic reactions. Generally, the role of metal oxides can be summarized as follows: i)Several types of heterojunctions (such as conventional type‐II heterojunction, p–n junction and direct Z‐scheme heterojunction) between TiO 2 and metal oxides can be formed, thus promoting the charge separation; ii)Metal oxides can act as reduction cocatalysts and oxidation cocatalysts, which trap the photogenerated electrons and holes, respectively, thus providing active sites for photocatalytic redox reactions; iii)Metal oxides can extend the absorption range from UV to visible light region.…”

“…It is reported that the deposition of oxidation cocatalysts can also drive the separation of photogenerated charge carriers, become oxidation sites and catalyze the oxidation reactions such as photocatalytic degradation of pollutants and O 2 evolution. The bicomponent metal and metal oxide cocatalysts, such as Pt–CoO x , Pt/Ag–MnO x , Pt/Ag/Au/Pd/Ru–RuO 2 , Pt–Fe 2 O 3 and Pd–IrO x , have been extensively investigated as efficient cocatalysts for photocatalytic reactions. The comodification of bifunctional cocatalysts are favorable to the transfer of photogenerated electrons and holes trapped by reduction cocatalysts (noble metals) and oxidation cocatalysts (metal oxides), respectively ( Figure ) .…”

“…Owing to the fact that the interface is the location where the charge carriers separate, transfer and recombine, controlling the interfacial structures to regulate the type and number of contact interfaces is imperative to improve the efficiency of charge transfer and separation. Accordingly, the integration structure of cocatalysts can be classified into three major types: random deposition, facet‐dependent selective deposition and core–shell structure ( Figure ).…”

“…Similarly, Liu et al designed a ternary heterojunction photocatalyst with α‐Fe 2 O 3 and Pt selectively decorated onto the oxidative {001} and reductive {101} facets . Compared to the counterparts with randomly deposited dual cocatalysts, the ternary Fe 2 O 3 –TiO 2 –Pt photocatalyst showed appealing photocatalytic hydrogen production rate, which was attributed to the cooperative enhancement from the facet‐induced and heterojunction‐induced effect.…”