Decomposition of Methanol on Supported Pd–Au Catalyst for Recovery of Unused Waste Heat at Low Temperature

Abstract

Decomposition of methanol into CO and H₂ on supported Pd based catalyst was studied for recovery of unused heat at around 473 K. Decomposition of CH₃OH into CO and H₂ proceeded at lower temperature with greater endothermic heat compared with the CH₃OH steam reforming reaction. Effects of additives to Pd were studied and it was found that the addition of Au or Pt was effective for increasing catalytic activity around 473-523 K. In particular, Pd with 30 wt% Au added was the most active for CH₃OH decomposition into CO and H₂, and H₂ yield on Pd–Au(7 : 3)/Al₂O₃ was 51 % at 523 K. Although high H₂ yield was achieved, yield of dimethyl ether (DME) was also high on this catalyst, in particular, at low temperature around 523 K. Formation of DME was significantly suppressed by using BaZrO₃ for the support and also mixing BaZrO₃ with Al₂O₃ for support of Pd–Au bimetal catalyst. Therefore, use of BaZrO₃ for the support was effective for increasing CO selectivity and Pd–Au(9 : 1)/BaZrO₃–Al₂O₃(1 : 1) was highly active for CH₃OH decomposition into CO and H₂, and negligible amount of DME was formed around 523 K.