Production of high surface area mayenite (C12A7) via an assisted solution combustion synthesis (SCS) toward catalytic soot oxidation

Abstract Mayenite (Ca₁₂Al₁₄O₃₃) is an attractive, non-expensive material, conventionally prepared over 1300 °C via solid-state reaction, producing a solid with low specific surface area (1 m²/g). Although a recent alternative allowed mayenite formation from 400 °C using hydrothermal method, it still requires a ball-milling step to increase the specific surface area (≥20 m²/g), which is costly and energy-consuming, involving specialized equipment. Herein, we report a new, cost-effective and simple way to produce porous mayenite with enhanced textural properties at lower temperatures (˜275 °C). Initially, non-porous mayenite was directly produced from 250 °C via a self-combustion reaction of nitrates with a double-fuel mixture. Furthermore, the addition of oxalic acid was implemented, obtaining porous mayenite after calcination of a preformed precursor and boosting its specific surface area and pore volume up to 74 m²/g and 0.3 cm³/g, respectively. Such textural enhancement notably increased mayenite catalytic properties in the soot oxidation reaction.