Effects of Al distribution in the Cu-exchanged AEI zeolites on the reaction performance of continuous direct conversion of methane to methanol

Highly Effective Cu/AEI Zeolite Catalysts Contribute to Continuous Conversion of Methane to Methanol

“…39 The lessened proportion of Q 4 (1Al) and Q 4 (2Al) calculated from the peak area at −101 and −111 ppm of 29 Si MAS NMR for AEI-t verified the diminution in the Al pairs as well as the framework Al atoms along with calcination temperature (Figures 2B and S3 and Table 1). 13,35,40 The chemical composition of the Cu/AEI samples determined by ICP-AES is listed in Table 2. The Si/Al ratio of all of the samples was around 11.…”

“…8−12 In our previous work, the effect of the framework Al distribution on the exchanged Cu species was elucidated; the high proportion of Al pairs was verified to be beneficial for the formation of dicopper species and thereby improve the reaction performance. 13 Pursuing a high proportion of Al pairs in the AEI zeolite is an effective way to further improve the reactivity.…”

“…Recently, Xiao′s group successfully employed ZSM-5, β, ferrierite (FER), and many other zeolites as the starting materials to synthesize AEI zeolite by the IZC method, , which greatly enriched the starting materials for AEI zeolite synthesis. It is well-recognized that the starting materials such as Si and Al sources, types of OSDA, and cations significantly influenced the physicochemical properties of zeolites, especially framework Al distributions. − In our previous work, the effect of the framework Al distribution on the exchanged Cu species was elucidated; the high proportion of Al pairs was verified to be beneficial for the formation of dicopper species and thereby improve the reaction performance . Pursuing a high proportion of Al pairs in the AEI zeolite is an effective way to further improve the reactivity.…”

Zeolite-based catalysts for oxidative upgrading of methane: design and control of active sites

“…[57][58][59][60][61] Recently, we developed a highly active catalyst for the partial oxidation of methane into methanol using N 2 O as an oxidant, which was achieved by controlling the position of the framework Al atoms. 62 OSDAs with/without Na cations strongly influence the position of the framework Al atoms in AEI-type structures; the AEI-type zeolite synthesized with Na cations (denoted as AEI(Na)) had a greater number of paired Al sites compared to that synthesized without Na cations (AEI(Na-free)). Such a paired Al-rich environment generated a relatively larger number of dicopper species ([Cu 2 (μ-O)] 2+ ) via ion exchange, resulting in higher catalytic performance (Fig.…”

Impacts of framework Al distribution and acidic properties of Cu-exchanged CHA-type zeolite on catalytic conversion of methane into methanol followed by lower hydrocarbons

“…Very recently, we have found that the Al distribution has greatly affected the state and location of the metal species introduced and catalytic activities. 23,24 However, the impact of the Al distribution in the CHA-type zeolite on Cu-exchanged zeolites and their catalytic performance in the MTM reaction have not been clarified to date.…”