Improved charge transfer and morphology on Ti-modified Cu/γ-Al2O3/Al catalyst enhance the activity for methanol steam reforming

The metal-oxide interaction has been considered as an effective factor for catalytic performance in methanol steam reforming. In this work, Ti modified Cu/γ-Al₂O₃/Al catalyst was prepared by anodization technology. It is found that the addition of Ti can largely increase the surface area of the carrier and thus improve the dispersion of copper. The co-existence of Ti⁴⁺ and Ti³⁺ makes the charge transfer between Cu and Ti easier, which improves the redox performance of copper. The DFT calculations reveal that Ti also enhance the adsorption capacity of water and methanol on the surface of the catalysts. Besides, Ti also reduce the acid density on the carrier, inhibit methanol dehydration reaction and thereby reduce the selectivity of the DME. The optimal catalyst CuTi_1.9/γ-Al₂O₃/Al achieves nearly 100% conversion at 275 °C, while the methanol conversion of Cu/γ-Al₂O₃/Al is 82%. And the H₂ output of CuTi_1.9/γ-Al₂O₃/Al reached 69.17 mol/(kg_cat·h) at 300 °C.