Direct synthesis of dimethyl ether from CO₂ hydrogenation over Cu–ZnO–ZrO₂/SO₄²⁻–ZrO₂ hybrid catalysts: effects of sulfur-to-zirconia ratios

Abstract

Methanol can be dehydrated to form DME over sulfated zirconia catalysts via pathway I, if the sulfur content is low, and pathway II, if the sulfur content is high.

Time evolution of the CO2 hydrogenation to fuels over Cu-Zr-SBA-15 catalysts

“…In addition, the evolution of our DRIFTS-spectra shows no indication of any consumption of the produced methanol molecules. This is in contrast to what has been reported earlier when formation of DME was associated with combining CH3OH and CH3O -that were attached on acidic and basic sites of the catalyst's surface, respectively 8,35,36,66 . The catalysts studied here show a preference for methoxy attachment that apparently suppresses surface attachment of methanol and changes the DME formation route.…”

“…The other two peaks are between 500-600 °C and these are assigned as strong acid sites. No peak was observed for weak acid sites that typically appear between 100-200 °C 35,36 . The number of medium strength acid sites is larger for Cat_EIWI compared to Cat_Inf, while the number of strong acid sites is similar for both catalysts.…”

“…In our study we see that Cat_Inf is selective to DME formation. Based on this we infer that the stronger medium acid strength sites increases the surface affinity to methoxy, which is related to the electronegativity of its oxygen 36 . An increased surface methoxy concentration facilitates interaction between neighboring methoxy groups to form DME.…”

Performance of CuO–ZnO–ZrO2 and CuO–ZnO–MnO as metallic functions and SAPO-18 as acid function of the catalyst for the synthesis of DME co-feeding CO2

“…This problem affects HSZM-5 zeolite to a lesser extent, although it is also significant [21,42,49]. Witoon et al [50] have used a sulfated zirconia catalyst for the direct synthesis of DME from CO 2 hydrogenation.…”

Effect of hierarchical meso–macroporous alumina-supported copper catalyst for methanol synthesis from CO2 hydrogenation

“…The catalytic hydrogenation of CO 2 to methanol is considered one of the most promising processes because methanol can be used as an energy carrier for fuel cell application [1][2][3]. Moreover, methanol can be converted to dimethyl ether (DME) [4,5] which is considered as a feasible fuel for diesel engines [6,7], or into higher hydrocarbons according to methanol-to-olefins (MTO) process [8][9][10][11].…”