Improvement of the Photocatalytic Activity of ZnO/Burkeite Heterostructure Prepared by Combustion Method

Abstract

In this work, a novel route is discussed to produce in one step ZnO/Burkeite powders by the modified solution combustion method. The ZnO particles enhance the photocatalytic activity in the degradation of Rhodamine B, in which Burkeite mineral acts as a support due to the pH-dependent morphology of the particle aggregates of the as-synthesized powders. The X-ray diffraction (XRD) characterization shows the presence of a heterostructure: ZnO/Burkeite. The Scanning Electron Microscopy (SEM) image shows a morphological dependence with the pH of the solution used for the synthesis. The results show that the system with the highest degradation (92.4%) corresponds to the case in which ZnO/Burkeite heterostructure was synthesized with a pH 11.

Prominent roles of Ni(OH)2 deposited on ZnIn2S4 microspheres in efficient charge separation and photocatalytic H2 evolution

“…To understand the mechanism of the enhanced photocatalytic H 2 evolution over Ni(OH) 2 /ZnIn 2 S 4 , the role of the deposited 7a, aer the photo-deposition of Au on the composite, several dark gray nanoparticles clearly appear on the surface of the crystalline ZnIn 2 S 4 only. 7,8 A HRTEM (Fig. 7b) analysis further indicates that the lattice fringe of 0.23 nm in a dark gray nanoparticle matches the crystallographic plane (111) of metallic cubic-phase Au.…”

“…2e and f) of 6% Ni(OH) 2 /ZnIn 2 S 4 composite reveals that the crystalline Ni(OH) 2 are well deposited onto the surface of well-crystalline ZnIn 2 S 4 to form heterostructures with the intimate interfaces. 7,8 The lattice fringes with the spacing of ca. 0.32 nm and 0.27 nm well correspond to the crystallographic plane (102) of hexagonal ZnIn 2 S 4 and the crystallographic plane (100) of hexagonal Ni(OH) 2 , respectively.…”

“…[4][5][6] Unfortunately, the direct application of these semiconductors themselves for photocatalytic H 2 production is almost infeasible mainly due to their rapid charge recombination. [7][8][9] For an efficient photocatalytic H 2 production reaction, it is indispensable to load a noble metal such as Pt, Pd, Ag, or Au as a cocatalyst on the host semiconductors. [10][11][12][13] The noble metals as cocatalysts can not only facilitate the separation of electron-hole pairs over host semiconductor effectively, but also function as active sites for H 2 production.…”

Enhancing Photocatalytic Activity of ZnO Nanoparticles in a Circulating Fluidized Bed with Plasma Jets

“…Among various semiconductors, zinc oxide (ZnO) with the wide band gap (3.37 eV) [4], large exciton blinding energy (60 meV) [5], good photoelectric properties, non-toxicity, abundance and environmental stability [6,7] perform much better than other photocatalysts. Therefore, ZnO has been widely researched for various applications including photocatalysts [8][9][10], chemical sensors [11], transparent electrodes [12], solar cells [13] and luminescent materials [14,15]. Especially, ZnO performs well on the photocatalytic.…”

“…However, ZnO nanoparticles as photocatalyst also suffers several problems: (ⅰ) The bandgap of ZnO is too wide for electron transition, which makes it only respond to the ultraviolet region of sunlight [8], and the ultraviolet region only occupies a ratio of 5-7% sunlight. To expand the region of light response, modification of ZnO nanopowders is essential.…”