Reactive metal-support interaction in the Cu-In(2)O(3) system: intermetallic compound formation and its consequences for CO(2)-selective methanol steam reforming

The reactive metal-support interaction in the Cu-In(2)O(3) system and its implications on the CO(2) selectivity in methanol steam reforming (MSR) have been assessed using nanosized Cu particles on a powdered cubic In(2)O(3) support. Reduction in hydrogen at 300 °C resulted in the formation of metallic Cu particles on In(2)O(3). This system already represents a highly CO(2)-selective MSR catalyst with ~93% selectivity, but only 56% methanol conversion and a maximum H(2) formation rate of 1.3 µmol g(Cu)(−1) s(−1). After reduction at 400 °C, the system enters an In(2)O(3)-supported intermetallic compound state with Cu(2)In as the majority phase. Cu(2)In exhibits markedly different self-activating properties at equally pronounced CO(2) selectivities between 92% and 94%. A methanol conversion improvement from roughly 64% to 84% accompanied by an increase in the maximum hydrogen formation rate from 1.8 to 3.8 µmol g(Cu)(−1) s(−1) has been observed from the first to the fourth consecutive runs. The presented results directly show the prospective properties of a new class of Cu-based intermetallic materials, beneficially combining the MSR properties of the catalyst’s constituents Cu and In(2)O(3). In essence, the results also open up the pathway to in-depth development of potentially CO(2)-selective bulk intermetallic Cu-In compounds with well-defined stoichiometry in MSR.