• Tailored W–P–Al₂O₃ catalyst with balanced acidity delivers high methanol conversion and DME selectivity. • Stable performance maintained for over 500 h at atmospheric pressure and WHSV of 1 h⁻¹. • Low metal loading while maximizing DME yield. • Selective methanol dehydration achieved under mild, energy-efficient reaction conditions. • Water-tolerant operation supports realistic, low-purification methanol feeds and sustainable DME production. Methanol dehydration to dimethyl ether (DME) is a key catalytic route for producing clean fuels and chemical intermediates under mild conditions. In this study, a series of tungsten- and phosphorus-modified γ-Al₂O₃ catalysts was synthesized via wet impregnation to achieve controlled tuning of surface acidity and provide an industrially acceptable DME synthesis catalyst. The comprehensive physicochemical characterization revealed that the synergistic interaction between tungsten and phosphorus leads to highly dispersed WOₓ species and the formation of stabilized Al–O–P linkages, resulting in an optimized distribution of weak-to-moderate acid sites. Among the synthesized catalysts, WAP-3 exhibited superior catalytic performance, achieving close to 86% methanol conversion with nearly 100% DME selectivity at 280°C under atmospheric pressure. Notably, the catalyst demonstrated notable long-term stability exceeding 500 h time-on-stream and retained significant activity under water-diluted feed conditions. The enhanced performance is attributed to the balanced acidity and suppression of bulk WO₃ formation; it suppresses common deactivation pathways such as coke formation and water poisoning, which are well known. Compared to previously reported alumina-based systems, the present catalyst shows improved stability and efficiency, highlighting the importance of controlled acidity engineering in designing robust catalysts for sustainable DME production. These results highlighted the potential of low-metal-loading, alumina-based catalysts for sustainable and energy-efficient continuous DME production.
Valappil et al. (Wed,) studied this question.