Strategy for Modifying Layered Perovskites toward Efficient Solar Light-Driven Photocatalysts for Removal of Chlorinated Pollutants

Monica Raciulete,Florica Papa,Ioan Balint,Irina Atkinson,Jeanina Pandele-Cusu,Daniela C Culita,Veronica Bratan,Catalin Negrila,Cornel Munteanu

doi:10.3390/catal10060637

Abstract

We have explored an efficient strategy to enhance the overall photocatalytic performances of layered perovskites by increasing the density of hydroxyl group by protonation. The experimental procedure consisted of the slow replacement of interlayer Rb+ cation of RbLaTa2O7 Dion-Jacobson (DJ) perovskite by H+ via acid treatment. Two layered perovskites synthesized by mild (1200 °C for 18 h) and harsh (950 and 1200 °C, for 36 h) annealing treatment routes were used as starting materials. The successful intercalation of proton into D-J interlayer galleries was confirmed by FTIR spectroscopy, thermal analyses, ion chromatography and XPS results. In addition, the ion-exchange route was effective to enlarge the specific surface area, thus enhancing the supply of photocharges able to participate in redox processes involved in the degradation of organic pollutants. HLaTa_01 protonated layered perovskite is reported as a efficient photocatalyst for photomineralization of trichloroethylene (TCE) to Cl− and CO2 under simulated solar light. The enhanced activity is attributed to combined beneficial roles played by the increased specific surface area and high density of hydroxyl groups, leading to an efficiency of TCE mineralization of 68% moles after 5 h of irradiation.

Highlights

Solar energy represents one of the most attractive, available and accessible solutions for a variety of worldwide issues including water and air purification
Following our previous work on RbLaTa-based layered perovskites [8], the present study focuses on the photocatalytic degradation of trichloroethylene (TCE) over HLaTa2 O7 layered perovskite obtained by protonation of RbLaTa2 O7
We have explored an efficient strategy to increase the density of active sites of layered perovskites by protonation

Summary

Introduction

Solar energy represents one of the most attractive, available and accessible solutions for a variety of worldwide issues including water and air purification. Introducing appropriate defects onto the surface of layered materials by substitution of parent cations has a positive effect on the electronic structure and optical absorption properties of the host materials [5]. Another interesting feature is using the perovskite interlayer space as reactions sites, retarding the recombination process by a better physical separation of the photogenerated carriers. Their interlayer guests are ion-exchangeable with various foreign species, being a facile method for the fabrication of layered assemblies [6,7]

Methods

Results

Conclusion