Structural relationships and the synergistic catalytic mechanism of CuO/ZnO/Ga2O3 ternary catalysts in low-temperature methanol steam reforming

Abstract

In this study, the constitutive relationships of CuO/ZnO, CuO/Ga₂O₃, ZnO/Ga₂O₃ bimetallic catalysts and CuO/ZnO/Ga₂O₃ ternary catalysts were systematically investigated to reveal the mechanism of the metal–component interactions on the catalytic performance. In the bimetallic system, ZnO inhibits CuO sintering through a physical barrier effect, the CuO/Ga₂O₃ interface promotes the formation of adsorbed oxygen to enhance the resistance to carbon deposition, and the ZnO/Ga₂O₃ solid-solution structure significantly enhances the electron-transfer efficiency. In the ternary catalyst with an M²⁺ : M³⁺ ratio of 3 : 1, the high specific surface of the layered structure with abundant active sites enabled CuO/ZnO/Ga₂O₃-3 to exhibit optimal performance: the synergistic effect between the CuO and Zn₉Ga₂O₁₂ crystalline surfaces enhanced electron transfer and metal–carrier interactions, and the ratio of adsorbed oxygen reached 78.42%, which effectively promoted CO oxidation and CO₂ generation. When applied to methanol steam reforming (MSR), the catalyst achieved 99.89% methanol conversion, 55.30 mmol g⁻¹ h⁻¹ H₂ production rate, and only 0.91% CO concentration, combining highly efficient catalytic activity and anti-sintering stability. The results provide a theoretical basis for the structural design and performance optimization of multi-component catalysts.