Multifunctional continuous solid solution Na0.9Mg0.45Ti3.55O8-Na2Fe2Ti6O16: Preparation, characterization, magnetism, dual absorption, adsorption, and photocatalysis

Abstract

Multifunctional continuous solid solutions Na0.9Mg0.45Ti3.55O8-Na2Fe2Ti6O16 (NFMTO-x) were synthesized via a one-step hydrothermal method by controlling the ratio of Mg and Fe. The NFMTO-x continuous solid solutions share same monoclinic structure of space group C2/m and same morphology of long hexagonal nanosheets with Na0.9Mg0.45Ti3.55O8 (NMTO) and Na2Fe2Ti6O16 (NFTO). XPS and EDX results reveal five elements Na, Mg, Fe, Ti, and O in the continuous solid solutions to confirm the change in Mg and Fe contents. The NFMTO-x continuous solid solutions enjoy dual absorption, significantly expanding their visible light response in comparison with pure NMTO. The organic pollutant methylene blue (MB) was effectively degraded through the NFMTO-x adsorption and photocatalysis, which exhibits higher performances than the pure NMTO and NFTO. Effective adsorption towards dyes is an important prerequisite to promote photocatalytic effectivity. LC-MS and TOC tests at different times reveal that MB dye was effectively mineralized to some degradation intermediates. NFMTO-x samples also have a certain capacity for CO2 methanation, converting CO2 to CO and CH4. The magnetic properties let us easily collect the powders from water after photodegradation for recycling utilization. The electron spin resonance identified O2− as the important active group in photocatalytic degradation. This research provides a significant multifunctional material used in water purification.