Perovskite nanostructures assembled in molten salt based on halogen anions KX (X = F, Cl and Br): Regulated morphology and defect-mediated photocatalytic activity

Abstract

Defect engineering of semiconductors provides an effective strategy for improving photocatalytic performance without doping alien elements. Understanding the defect and defect-related photocatalytic activity of semiconductors could lead to new horizon in the rational design of photocatalysts for practical applications. Herein, novel oxygen-deficiency contained perovskite CaCu 3 Ti 4 O 12 with tunable structures of cube, nanoparticle and octahedron were for the first time synthesized via a feasible molten salt reaction approach depending on halogen anions of employed salts KX (X = F, Cl and Br). Formation mechanisms of the different structures were revealed on the basis of innate characters of the selected halide anions. Assorted shapes display strong visible light absorption, which is interconnected with Ti displacement and oxygen deficiency. The photocatalytic performances of those three homologues were evaluated by an antibiotic degradation under visible light illumination. A superior photoefficiency is achieved for octahedron shaped crystal, which reduces 95.86% total organic carbon within 60 min and exhibits the reaction rate normalized to surface area of 1.261 × 10 −2 g min −1 m −2 , approximately 3.687 and 3.474 times larger than its counterparts. The outstanding degradation efficiency is ascribed to the synergetic roles of effective charge transfer, oxygen deficiencies and critical roles of active radicals resulting in carrier separation and efficiency enhancement. This work provides fundamental understanding of the morphology tailoring and defect controlling towards exploring new generation of visible light photocatalysts for environment and energy applications.

Composite structure and enhanced photocatalytic activity in Mn–Co–Ni–O/LaMnO3 microparticles

“…For the S5 sample, the particles are significantly refined, indicating that smaller particles can be obtained by compositing the two phases at an appropriate proportion. More importantly, reducing the particle size of the photocatalyst will shorten the transfer path of the charge carriers, which leads to efficient carrier separation and improved photocatalytic performance [3].…”

“…Since decades, many efforts have been made to improve the photocatalytic performances of photocatalysts, such as through textural design, doping, noble metal loading, forming semiconductor composites and exploring novel visible-light-induced photocatalysts [3][4][5][6]. Sun et al reported that compared to non-doped and singly doped photocatalysts, the light absorption performance of Co and Ni co-doped cryptomelane was significantly improved and the degradation rate of phenol was increased, mainly due to the increased specific surface area and the variations in the relative contents of Mn 4+ /Mn 3+ ions [7].…”

Molten‐Salt Technology Application for the Synthesis of Photocatalytic Materials

“…These ions directly affect the growth rate, growth direction, and the decrease in specific surface energy of catalyst crystal, thus forming the morphology of lamellar, tubular, nanorod, and polyhedron. [ 74 ] In addition, molten salt can also act as a template. [ 58 ] When the heating reaction stops, with the gradual cooling of the molten salt, the salt crystals begin to precipitate, and the reactants in the system will be coated on the surface of the salt.…”

Photoreduction properties of novel Z-scheme structured Sr0.8La0.2(Ti1−δ4+Tiδ3+)O3/Bi2MoO6 composites for the removal of Cr(vi)

“…16,21 Meanwhile, it is unanimously accepted that introducing O v is also an effective way to separate photogenerated electron-hole pairs by capturing electrons. [17][18][19] To enhance the transfer efficiency of the photogenerated carriers, several strategies have been developed, such as hybridizing expensive metal nanoparticles, such as Au and Ag nanoparticles, with photocatalysts, and compositing goodconductivity material such as g-C 3 N 4 with photocatalysts. 20 In this study, we designed a photocatalyst that was expected to superpose the effects of O v and Z-scheme heterojunction on prolonging the lifetime of photogenerated carriers as well as improving the transfer of photogenerated electrons.…”