Synergistic hydrophobicity and Si-O-Mn interfacial coupling of hierarchical xMCMnOx for low-temperature ammonia-selective catalytic reduction

Hierarchical x MCMnO x was fabricated via facile in-situ silane confinement strategy. • Si-O-Mn are formed by the interaction of amorphous siloxane network and MOF precursor. • Mn 4+ + Ce 3+ ⇌Mn 3+ + Ce 4+ cycle forms a dynamic equilibrium to produce oxygen vacancies. • 3MCMnO x shown superior activity for low-temperature NH 3 -SCR with H 2 O/SO 2 resistance. Developing high-efficiency catalysts for the selective catalytic reduction of NO x with NH 3 (NH 3 -SCR) is of great significance for achieving ultra-low NO x emissions. Herein, hierarchical x MCMnO x hollow nanorod hybrids were fabricated via a facile in-situ silane confinement strategy using Ce-doped Mn-BTC modified with MTMS (methyltrimethoxysilane) as the sacrificial template for NH 3 -SCR reaction. Systematic studies demonstrated that the tight chemical interaction between the amorphous siloxane network and the MOF precursor facilitated the highly dispersed distribution of the doped Ce species around the Mn active sites, forming abundant Si-O-Mn interface covalent bonds and strong metal-metal interactions (Mn 4 + + Ce 3+ ⇌ Mn 3+ + Ce 4+ ). Benefiting from the stronger NH₃ adsorption capacity, abundant reactive oxygen species, and surface-enriched hydrophobic methyl groups, the optimized 3MCMnO x promoted the Eley-Rideal (E-R) reaction pathway via strong Si-O-Mn interfacial coupling, achieving a 100% NO conversion rate within the temperature range of 150–300 °C at a GHSV of 36000 h −1 and robust H 2 O/SO 2 tolerance. Furthermore, the universality of this way was verified in analogous Co-based and Cu-based systems. This work opens a new avenue for the design of efficient and durable MOF-derived denitration catalysts for non-electric industries. Download: Download high-res image (250KB) Download: Download full-size image