Abstract
Triclinic ZnAPO-34 and triclinic FAPO-34 were synthesized by hydrothermal crystallization from zinc(II)- and iron(II)-containing gels. The products are thermally stable up to 900 °C. XANES and EXAFS analyses were applied to study the local environment of zinc in the ZnAPO-34 samples, while XANES analysis and Mössbauer spectroscopy were performed on the iron-substituted samples. Zn(II) remains in the same oxidation state during synthesis and after thermal treatment, while iron exhibits Fe(II) and Fe(III) oxidation states. Analysis of the local structure showed that Zn(II) is located on tetrahedral sites of the framework, while Fe(II) and Fe(III) are present on octahedral sites. Infrared study of carbon monoxide adsorption at 100 K showed the presence of strong Brønsted acid sites on the Zn and Fe(II) samples, indicating the substitution of the metals in the framework. Rhombohedral FAPO-34 can be reversibly oxidized in the infrared cell, evidencing the disappearance of the Brønsted acid sites in the Fe(III) oxidation state.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
