Steam reforming of methanol for hydrogen production over attapulgite-based zeolite-supported Cu-Zr catalyst

Abstract

The methanol steam reforming (MSR) was one of the promising technologies for high-efficiency hydrogen production. The key issue for MSR was the development of catalysts. In this paper, the Cu-Zr components supported on the attapulgite-based zeolite (AZ) was prepared and applied into MSR reaction. MSR activity test demonstrated the synthesized micropore and mesopore channels in AZ enhanced the catalytic performance through promoting the heat and mass transfer. Various characterizations such as N2 adsorption–desorption, XRD, H2-TPR, XPS, SEM, HRTEM, H2/CO2-TPD, H2 pulse chemisorption and TGA confirmed Zr addition significantly increased the distribution of active metal particles and metallic surface area and facilitated the formation of Cu0/Cu+-ZrOxHy interface sites. Among the prepared catalysts, 1Cu1Zr/AZ catalyst possessed the maximum Cu0/Cu+-ZrOxHy interface sites and metallic surface area, therefore it exhibited the best catalytic performance for MSR, and its hydrogen productivity reached to 655.1 mmol/gcat/h. In addition, the Cu0/Cu+-ZrOxHy interface sites in Zr-modified Cu/AZ catalysts inhibited the active metal sintering and coke formation. The possible mechanism of MSR over 1Cu1Zr/AZ was proposed, in which Cu0/Cu+ species promoted the decomposition of methanol and intermediates, meanwhile, the Cu0/Cu+-ZrOxHy interface sites helped to continuously provide the –OH groups through steam activation by hydroxylated Zr species. These cooperative effects promoted the oxidation of intermediates and water–gas shift reaction, resulting in producing more H2 and CO2. This work offers a possibility for preparing available and economical attapulgite-based zeolite-supported Cu-Zr Catalyst for MSR.