Enhanced Catalytic Performance of Egyptian Red Clay Modified with Zirconia Nanoparticles for Methanol Dehydration to Dimethyl Ether

In this study, Egyptian red clay (ERC) was modified with various percentages of ZrO₂ nanoparticles using a chemical precipitation method to test its effectiveness for methanol dehydration into dimethyl ether (DME). The most active catalyst was treated with 5–10 wt. % SO₄²⁻ via impregnation. The physicochemical characteristics of the catalysts were examined using XRD, XRF, FTIR, N₂-sorption, and TEM analysis. Catalyst acidity was assessed through isopropyl alcohol dehydration and interactions with pyridine and 2,6-dimethyl pyridine. Results demonstrated that, the catalytic performance of the ERC was greatly influenced with % ZrO₂, catalyst weight and sulfation process. The 7% SO₄²⁻/20% ZrO₂/ERC catalyst offered a maximum DME yield of ~ 94% at 250 °C with 100% selectivity to DME. This catalyst offered a long-term stability over seven days with almost the same activity and selectivity. Brønsted acidic sites with weak and intermediate strengths were responsible for such enhancement. Our findings highlight the critical roles of specific surface area and acidity in enhancing catalytic performance, positioning ERC-supported zirconia modified with SO₄²⁻ as a cost-effective, environmentally friendly, and recyclable catalyst for DME production.

Graphical Abstract