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 ... -  《-》

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 《-》

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 ... -  《-》

Design of Heterostructured Hollow Photocatalysts for Solar-to-Chemical Energy Conversion.

Direct conversion of solar energy into chemical energy in a sustainable manner is one of the most promising solutions to the energy crisis and environmental issues. Fabrication of highly active photocatalysts is of great significance for the practical applications of efficient solar-to-chemical energy conversion systems. Among various photocatalytic materials, semiconductor-based heterostructured photocatalysts with hollow features show distinct advantages. Recent research efforts on rational design of heterostructured hollow photocatalysts toward photocatalytic water splitting and CO2 reduction are presented. First, both single-shelled and multishelled heterostructured photocatalysts are surveyed. Then, heterostructured hollow photocatalysts with tube-like and frame-like morphologies are discussed. It is intended that further innovative works on the material design of high-performance photocatalysts for solar energy utilization can be inspired.

Zhang P ，Lou XWD 《-》

A Facile Surface Passivation of Hematite Photoanodes with Iron Titanate Cocatalyst for Enhanced Water Splitting.

The surface modification of semiconductor photoelectrodes with passivation overlayers has attracted great attention as an effective strategy to improve the charge separation and charge transfer processes across the semiconductor-electrolyte interface. In this work, a thin Fe2 TiO5 layer was decorated on nanostructured hematite nanoflake and nanocoral photoanodes (by thermal oxidation of iron foils) by a facile water-based solution method. Photoelectrochemical measurements show that the Fe2 O3 /Fe2 TiO5 heterostructure exhibits an obvious enhancement in photoelectrochemical water oxidation performance compared to the pristine hematite. For example, at 1.23 V versus the reversible hydrogen electrode (VRHE ) in 1 m KOH under AM 1.5 G (100 mW cm(-2) ) illumination, a 4-8× increase in the water oxidation photocurrent is achieved for Fe2 O3 /Fe2 TiO5 , and a considerable cathodic shift of the onset potential up to 0.53-0.62 VRHE is obtained. Moreover, the performance of the Fe2 O3 /Fe2 TiO5 heterostructure can be further improved by decoration with a SnOx layer. The enhancement in photocurrent can be attributed to the synergistic effect of Fe2 TiO5 /SnOx overlayers passivating surface states, and thus reducing surface electron-hole recombination.

Wang L ，Nguyen NT ，Schmuki P 《-》