Aluminum Distribution in Ferrierite Zeolites Influences the Performance of Methane Oxidation

Abstract

Abstract Transition‐metal‐free aluminosilicate FER‐type zeolite has been demonstrated to effectively catalyze methane to methanol using N 2 O as the oxidant with distorted tetra‐coordinated aluminum (Al IV‐2 ) and penta‐coordinated aluminum (Al V ) as potential active sites. However, the specific effects of Al distribution on the active Al species have not been thoroughly investigated. Herein, aluminosilicate FER‐type zeolites with controllable Al distribution were developed. Al distribution, including the arrangement and location of Al atoms, was characterized using 27 Al MQMAS/MAS and 29 Si MAS NMR spectra. The arrangement of aluminum, particularly the isolated Al and paired Al in as‐synthesized samples, influenced the proximity between oxidative and acidic sites in H‐type samples. Al locations involved the specific positioning of bifunctional sites and affected the final product. The increased CH 4 conversion at 250–275 °C of FER zeolite with Al preferential population at T4 sites confirmed the higher activity of Al species from T4 sites. Additionally, a higher proportion of Al atoms in 10‐ring channels facilitated the tandem conversion of methane to methanol on oxidative sites, followed by methanol to hydrocarbons on acidic sites at 300–375 °C. This study corroborated and expanded upon our recent research and highlighted the significant impact of Al distribution in FER zeolite on methane oxidation.