Study of supported heteropolyacid catalysts for one-step DME synthesis from CO and H.

Dimethyl ether (DME) is a versatile molecule, gaining increasing interest as a viable hydrogen and energy storage solution, pivotal for the transitioning from fossil fuels to environmentally friendly and sustainable energy supply. This research explores a novel approach for the direct conversion of CO to DME in a fixed-bed reactor, combining the Cu/ZnO/AlO methanol synthesis catalyst with supported heteropolyacids (HPAs). First, various HPAs, both commercially available and custom-synthesized, were immobilized on Montmorillonite K10. Using a wet impregnation procedure an almost ideal mono-layer of HPA on the support was achieved. The catalysts were further evaluated for their efficiency in direct synthesis of DME from CO/H in combination with the Cu/ZnO/AlO catalyst. Among the catalysts tested, tungstosilicic acid (HSiW) supported on K10 exhibited the most promising performance, achieving a DME yield ( ) of 7.06% and a molar productivity ( ) of 77.84 mol mol h. In a subsequent step, further tests using HSiW on various support materials identified ZrO as the most effective support, increasing the molar productivity to 125.44 mol mol h, while maintaining the DME yield. The results highlight the potential of applying HPA-based catalysts for sustainable DME synthesis directly from CO, emphasizing the critical role of the catalyst support for optimizing catalytic performance.