Methanol decomposition over copper particles incorporated in the interlayer regions of zinc aluminum silicate hydroxide

The decomposition of methanol over copper particles incorporated in the interlayer regions of zinc aluminum silicate hydroxide, reduced CuO/Zn-mica and Cu2+/Zn-mica, was studied. CuO/Zn-mica reduced with H, is high active for the decomposition, compared with reduced Cu2+/Zn-mica. Methanol is selectively converted at 200 degreesC to H-2 and CO in reduced CuO/Zn-mica, whereas the methanol decomposition over reduced Cu2+/Zn-mica forms formaldehyde as a by-product. IR data support that the decomposition over reduced CuO/Zn-mica proceeds via copper methoxide and/or copper formate as an intermediate. An adsorption of NH3 shows that the amount of the adsorption on reduced CuO/Zn-mica is about six times as large as that on reduced Cu2+/Zn-mica. The results indicate the difficulty of the reduction of copper ion in Cu2+/Zn-mica, compared with CuO/Zn-mica. These results support that the active site for methanol decomposition on reduced CuO/Zn-mica is metallic Cu in the interlayer regions of Zn-mica. (C) 2002 Elsevier Science B.V. All rights reserved.