Construction of Heterostructured Fe(2) O(3) -TiO(2) Microdumbbells for Photoelectrochemical Water Oxidation.

Designing advanced structures for heterojunction photocatalysts is an effective approach to enhance their performance toward solar-energy conversion. Herein we develop a facile synthetic strategy for the fabrication of Fe2 O3 -TiO2 microdumbbells. With the assistance of preferentially adsorbed hexadecylamine molecules, amorphous TiO2 nanospheres with tunable size are grown at the two ends of Fe-based metal-organic compound microrods. Subsequent annealing of the hybrid obtained leads to the formation of a novel heterostructured Fe2 O3 -TiO2 microdumbbell photocatalyst. Owing to the heterojunction formed and the unique structure, Fe2 O3 -TiO2 microdumbbells with optimized composition and morphology show enhanced performance for photoelectrochemical water oxidation, compared to monophasic Fe2 O3 and TiO2 materials as well as physical mixtures thereof.

Zhang P ，Yu L ，Lou XWD 《-》

Fabrication of Heterostructured Fe(2) TiO(5) -TiO(2) Nanocages with Enhanced Photoelectrochemical Performance for Solar Energy Conversion.

Photocatalysts with well-designed compositions and structures are desirable for achieving highly efficient solar-to-chemical energy conversion. Heterostructured semiconductor photocatalysts with advanced hollow structures possess beneficial features for promoting the activity towards photocatalytic reactions. Here we develop a facile synthetic strategy for the fabrication of Fe2 TiO5 -TiO2 nanocages (NCs) as anode materials in photoelectrochemical (PEC) water splitting cells. A hydrothermal reaction is performed to transform MIL-125(Ti) nanodisks (NDs) to Ti-Fe-O NCs, which are further converted to Fe2 TiO5 -TiO2 NCs through a post annealing process. Owing to the compositional and structural advantages, the heterostructured Fe2 TiO5 -TiO2 NCs show enhanced performance for PEC water oxidation compared with TiO2 NDs, Fe2 TiO5 nanoparticles (NPs) and Fe2 TiO5 -TiO2 NPs.

Zhang P ，Lu XF ，Luan D ，Lou XWD ... -  《-》

Sb-Doped SnO(2) Nanorods Underlayer Effect to the α-Fe(2) O(3) Nanorods Sheathed with TiO(2) for Enhanced Photoelectrochemical Water Splitting.

Here, a Sb-doped SnO2 (ATO) nanorod underneath an α-Fe2 O3 nanorod sheathed with TiO2 for photoelectrochemical (PEC) water splitting is reported. The experimental results, corroborated with theoretical analysis, demonstrate that the ATO nanorod underlayer effect on the α-Fe2 O3 nanorod sheathed with TiO2 enhances the PEC water splitting performance. The growth of the well-defined ATO nanorods is reported as a conductive underlayer to improve α-Fe2 O3 PEC water oxidation performance. The α-Fe2 O3 nanorods grown on the ATO nanorods exhibit improved performance for PEC water oxidation compared to α-Fe2 O3 grown on flat fluorine-doped tin oxide glass. Furthermore, a simple and facile TiCl4 chemical treatment further introduces TiO2 passivation layer formation on the α-Fe2 O3 to reduce surface recombination. As a result, these unique nanostructures show dramatically improved photocurrent density (139% higher than that of the pure hematite nanorods).

Han H ，Kment S ，Karlicky F ，Wang L ，Naldoni A ，Schmuki P ，Zboril R ... -  《-》

Enhanced Charge Separation through ALD-Modified Fe2 O3 /Fe2 TiO5 Nanorod Heterojunction for Photoelectrochemical Water Oxidation.

Hematite suffers from poor charge transport and separation properties for solar water splitting. This paper describes the design and fabrication of a 3D Fe2 O3 /Fe2 TiO5 heterojunction photoanode with improved charge separation, via a facile hydrothermal method followed by atomic layer deposition and air annealing. A highly crystallized Fe2 TiO5 phase forms with a distinct interface with the underlying Fe2 O3 core, where a 4 nm Fe2 TiO5 overlayer leads to the best photoelectrochemical performance. The favorable band offset between Fe2 O3 and Fe2 TiO5 establishes a type-II heterojunction at the Fe2 O3 /Fe2 TiO5 interface, which drives electron-hole separation effectively. The Fe2 O3 /Fe2 TiO5 composite electrode exhibits a dramatically improved photocurrent of 1.63 mA cm(-2) at 1.23 V versus reversible hydrogen electrode (RHE) under simulated 1 sun illumination (100 mW cm(-2) ), which is 3.5 times that of the bare Fe2 O3 electrode. Decorating the Fe2 O3 /Fe2 TiO5 heterojunction photoanode with earth-abundant FeNiOx cocatalyst further expedites surface reaction kinetics, leading to an onset potential of 0.8 V versus RHE with a photocurrent of 2.7 mA cm(-2) at 1.23 V and 4.6 mA cm(-2) at 1.6 V versus RHE. This sandwich photoanode shows an excellent stability for 5 h and achieves an overall Faradaic efficiency of 95% for O2 generation. This is the best performance ever reported for Fe2 O3 /Fe2 TiO5 photoanodes.

Li C ，Wang T ，Luo Z ，Liu S ，Gong J ... -  《-》

Enhanced Photoelectrochemical Water Oxidation Performance in Bilayer TiO(2) /α-Fe(2) O(3) Nanorod Arrays Photoanode with Cu : NiO(x) as Hole Transport Layer and Co-Pi as Cocatalyst.

Efficient charge transfer and excellent surface water oxidation kinetics are key factors in determining the photoelectrochemical (PEC) water splitting performance in photoelectrodes. Herein, a bilayer TiO2 /α-Fe2 O3 nanorod (NR) arrays photoanode was prepared with deposited Cu-doped NiOx (Cu : NiOx ) hole transport layer (HTL) and Co-Pi oxygen evolution reaction (OER) cocatalyst for PEC water oxidation. The hierarchical TiO2 /α-Fe2 O3 composite obtained by a secondary hydrothermal process exhibited an inapparent bilayer structure by embedding the underlayer TiO2 NR arrays at the bottom part of the post-grown α-Fe2 O3 NR arrays. The underlayer TiO2 NRs acted as an effective shuttling pathway for transferring photoelectrons generated in the upper hematite light absorber layer. A p-type inter-Cu : NiOx HTL was introduced to form a build-in p-n electric field between Cu : NiOx and α-Fe2 O3 NRs, which improved the hole extraction from α-Fe2 O3 to Co-Pi OER catalyst. As expected, the as-engineered TiO2 /α-Fe2 O3 /Cu : NiOx /Co-Pi photoanode displayed an excellent photocurrent density of 2.43 mA cm-2 at 1.23 V versus the reversible hydrogen electrode (VRHE ), up to 4.05 and 2.23 times greater than those of the bare α-Fe2 O3 (0.60 mA cm-2 ) and TiO2 /α-Fe2 O3 , respectively. The results demonstrate that the bottom-up engineering of electron-hole transport channels and cocatalyst modification is an attractive maneuver to enhance the PEC water oxidation activity in hematite and other photoanodes.

Li H ，Yin M ，Li X ，Mo R ... -  《-》