Basic evidences for methanol-synthesis catalyst design

Abstract

A series of Cu–ZnO/ZrO 2 catalysts (Zn at/Cu at, 0–3; ZrO 2, 42–44 wt.%) with markedly improved total (SA, 120–180 m 2/g) and metal surface area (MSA, 9–63 m 2/g) has been synthesized via the reverse co-precipitation under ultrasound field. Structure, adsorption properties and surface reactivity were probed by BET, XRD, TPR, N 2O-titration and TPD measurements of H 2, CO and CO 2, while the activity pattern in the CO 2 to CH 3OH hydrogenation reaction ( T R, 433–473 K; P R, 1.0 MPa) has been addressed. An optimum ZnO loading (Zn at/Cu at, 0.3–0.8) ensures higher process productivity, while the apparent structure sensitive character of the title reaction relies on the synergism of metal hydrogenation and oxide basic sites ( dual-site). The extent of the oxide/metal interface, probed by Cu δ+/Cu 0 and oxide-to-metal surface area (OSA/MSA) ratios, is the key-parameter allowing the normalization of the catalytic specific activity in a wide range (3–60%) of metal dispersion and the consequent structure insensitive character of the CO 2 hydrogenation reaction.