Showing papers by "Rengui Li published in 2017"

Positioning the Water Oxidation Reaction Sites in Plasmonic Photocatalysts

Abstract: Plasmonic photocatalysis, stemming from the effective light absorbance and confinement of surface plasmons, provides a pathway to enhance solar energy conversion. Although the plasmonic hot electrons in water reduction have been extensively studied, exactly how the plasmonic hot holes participate in the water splitting reaction has not yet been well understood. In particular, where the plasmonic hot holes participate in water oxidation is still illusive. Herein, taking Au/TiO2 as a plasmonic photocatalyst prototype, we investigated the plasmonic hot holes involved in water oxidation. The reaction sites are positioned by photodeposition together with element mapping by electron microscopy, while the distribution of holes is probed by surface photovoltage imaging with Kelvin probe force microscopy. We demonstrated that the plasmonic holes are mainly concentrated near the gold–semiconductor interface, which is further identified as the reaction site for plasmonic water oxidation. Density functional theory al...

Significance of Crystal Morphology Controlling in Semiconductor-Based Photocatalysis: A Case Study on BiVO4 Photocatalyst

Abstract: Precise control of the morphology and crystalline structure of semiconductor-based photocatalyst is crucial for improving the efficiency of solar energy conversion system. In this work, taking BiVO4 semiconductor photocatalyst as an example, we investigated the formation process for the regular decahedron BiVO4 crystals prepared by a convenient hydrothermal method and found that the synthesis is undergoing a dissolution–recrystallization process, concomitantly, the phase was transformed from tetragonal zircon type to monoclinic sheelite-type. By controlling the kinetics of crystal growth for BiVO4 through regulating acidity of the reaction solution, we rationally tune the morphology of monoclinic BiVO4 from regular decahedron crystals to short rod-like particles, particularly precisely modulate the proportion of {010}/{011} facets for the decahedron BiVO4. By tuning the crystalline phase and morphologies of BiVO4 crystal, we found that the photocatalytic water oxidation activity for the well-defined BiVO4...

Photocatalytic Water Splitting on Semiconductor-Based Photocatalysts

Abstract: Photocatalytic hydrogen production via solar water splitting is one of the most promising solutions for sustainable energy and environmental remedy issues. In the past few decades, photocatalytic water splitting has attracted increasing attention, and extensive efforts have been made to construct efficient heterogeneous water-splitting systems. In this chapter, we review the fundamental scientific advances in photocatalytic water splitting using semiconductor-based photocatalyst, especially in light-absorbing materials, photogenerated charge separation, dual-cocatalyst, and surface catalytic reactions. The chapter focuses on the advances achieved in particulate photocatalyst systems, Z-scheme photocatalyst systems, and hybrid natural–artificial photosynthesis systems. Additionally, technical and economic evaluation of hydrogen production via solar water splitting for potential applications is also briefly discussed. Finally, we present concluding remarks and future directions of photocatalytic water splitting for solar energy conversion.

Spatial distribution of active sites on a ferroelectric PbTiO3 photocatalyst for photocatalytic hydrogen production

Abstract: The separation of photogenerated charge carries is a challenging issue in artificial photocatalyst systems for solar energy conversion. It has been reported that spatial charge separation can take place between different facets of semiconductor-based crystals with regular morphology and facets, which could be used to rationally deposit cocatalysts on the right facets. However, the spatial separation of photogenerated electrons and holes is still a big challenge for a particulate photocatalyst without regular morphology and specific facets. In this work, we demonstrated that photogenerated electrons and holes can be regularly separated on ferroelectric PbTiO3 photocatalyst even without regular morphology and facets. The reduction cocatalyst and oxidation cocatalyst could be selectively formed on different sites via an in situ photochemical deposition method. It is found that the photoactivity and hydrogen production for PbTiO3 with spatially separated dual-cocatalysts is remarkably enhanced to more than 100 times greater compared to native PbTiO3, which is much higher than that the case of dual-cocatalysts with a random distribution. The intrinsic electric fields and spontaneous electric polarization in the bulk of PbTiO3 are proposed to play important roles in the spatial distribution of active sites on irregular PbTiO3 particles. Our work emphasizes the essential roles of two important factors, efficient charge separation strategy and the location of dual-cocatalysts on the right sites, to construct integrated artificial photocatalyst systems for solar energy conversion.

Inorganic assembly catalysts for artificial photosynthesis: general discussion

Abstract: Hiromu Kumagai, Leif Hammarström, Dong Ryeol Whang, Yuki Shinohara, Jose Martinez, Joshua Karlsson, Peter Summers, Christopher D. Windle, Masanori Kodera, Richard Cogdell, Kristine Rodulfo Tolod, Dogukan Hazar Apaydin, Etsuko Fujita, Alexander Kibler, Fengtao Fan, Elizabeth A. Gibson, Hisanao Usami, Akihide Iwase, Haruo Inoue, Akihiko Kudo, Devens Gust, Kazunari Domen, Flavia Cassiola, Katsuhiko Takagi, Sang Ook Kang, Akira Yamakata, Can Li, Licheng Sun, Hyunwoong Park, Young Soo Kang, Rengui Li, Fabio Di Fonzo, Tohru Setoyama and Osamu Ishitani