Yellowtail Snapper Ocyurus chrysurus

YELLOWTAIL SNAPPER OCYURUS CHRYSURUS 7.5CM Total lengt

Steering the methanol steam reforming reactivity of intermetallic Cu-In compounds by redox activation: stability vs. formation of an intermetallic compound-oxide interface.

To compare the inherent methanol steam reforming properties of intermetallic compounds and a corresponding intermetallic compound-oxide interface, we selected the Cu-In system as a model to correlate the stability limits, self-activation and redox activation properties with the catalytic performance. Three distinct intermetallic Cu-In compounds - Cu7In3, Cu2In and Cu11In9 - were studied both in an untreated and redox-activated state resulting from alternating oxidation-reduction cycles. The stability of all studied intermetallic compounds during methanol steam reforming (MSR) operation is essentially independent of the initial stoichiometry and all accordingly resist substantial structural changes. The inherent activity under batch MSR conditions is highest for Cu2In, corroborating the results of a Cu2In/In2O3 sample accessed through reactive metal-support interaction. Under flow MSR operation, Cu7In3 displays considerable deactivation, while Cu2In and Cu11In9 feature stable performance at simultaneously high CO2 selectivity. The missing significant self-activation is most evident in the operando thermogravimetric experiments, where no oxidation is detected for any of the intermetallic compounds. In situ X-ray diffraction allowed us to monitor the partial decomposition and redox activation of the Cu-In intermetallic compounds into Cu0.9In0.1/In2O3 (from Cu7In3), Cu7In3/In2O3 (from Cu2In) and Cu7In3/Cu0.9In0.1/In2O3 (from Cu11In9) interfaces with superior MSR performance compared to the untreated samples. Although the catalytic profiles appear surprisingly similar, the latter interface with the highest indium content exhibits the least deactivation, which we explain by formation of stabilizing In2O3 patches under MSR conditions

Steering the methanol steam reforming reactivity of intermetallic Cu-In compounds by redox activation: stability vs. formation of an intermetallic compound-oxide interface.

To compare the inherent methanol steam reforming properties of intermetallic compounds and a corresponding intermetallic compound-oxide interface, we selected the Cu-In system as a model to correlate the stability limits, self-activation and redox activation properties with the catalytic performance. Three distinct intermetallic Cu-In compounds - Cu7In3, Cu2In and Cu11In9 - were studied both in an untreated and redox-activated state resulting from alternating oxidation-reduction cycles. The stability of all studied intermetallic compounds during methanol steam reforming (MSR) operation is essentially independent of the initial stoichiometry and all accordingly resist substantial structural changes. The inherent activity under batch MSR conditions is highest for Cu2In, corroborating the results of a Cu2In/In2O3 sample accessed through reactive metal-support interaction. Under flow MSR operation, Cu7In3 displays considerable deactivation, while Cu2In and Cu11In9 feature stable performance at simultaneously high CO2 selectivity. The missing significant self-activation is most evident in the operando thermogravimetric experiments, where no oxidation is detected for any of the intermetallic compounds. In situ X-ray diffraction allowed us to monitor the partial decomposition and redox activation of the Cu-In intermetallic compounds into Cu0.9In0.1/In2O3 (from Cu7In3), Cu7In3/In2O3 (from Cu2In) and Cu7In3/Cu0.9In0.1/In2O3 (from Cu11In9) interfaces with superior MSR performance compared to the untreated samples. Although the catalytic profiles appear surprisingly similar, the latter interface with the highest indium content exhibits the least deactivation, which we explain by formation of stabilizing In2O3 patches under MSR conditions

Reactive metal-support interaction in the Cu-In2O3 system: intermetallic compound formation and its consequences for CO2-selective methanol steam reforming.

The reactive metal-support interaction in the Cu-In2O3 system and its implications on the CO2 selectivity in methanol steam reforming (MSR) have been assessed using nanosized Cu particles on a powdered cubic In2O3 support. Reduction in hydrogen at 300 °C resulted in the formation of metallic Cu particles on In2O3. This system already represents a highly CO2-selective MSR catalyst with ~93% selectivity, but only 56% methanol conversion and a maximum H2 formation rate of 1.3 µmol gCu -1 s-1. After reduction at 400 °C, the system enters an In2O3-supported intermetallic compound state with Cu2In as the majority phase. Cu2In exhibits markedly different self-activating properties at equally pronounced CO2 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 gCu -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 In2O3. In essence, the results also open up the pathway to in-depth development of potentially CO2-selective bulk intermetallic Cu-In compounds with well-defined stoichiometry in MSR