“…15 Unique coral-like porous SnO 2 hollow architectures synthesized by Liu and coworkers exhibited an enhanced photovoltaic performance due to their larger effective surface area for dye adsorption, light absorption and utilization than a spherical structure. 16 In addition, constructing hetero-junctions by combining semiconductors with noble metals, such as Au, 17 Ag, 18 Pt 19 and Pd, 13,20 or coupling with metal oxides, such as TiO 2 , 21,22 NiO, 23 Fe 2 O 3 , [24][25][26] ZnO, 27 and WO 3 , 28 has also been proved to be a very effective approach to prevent the recombination of electron-hole pairs. 29 The internal electric eld existing in hetero-junctions between the host semiconductor and the co-catalyst facilitates the separation of electron-hole pairs and induces faster carrier migration.…”