Understanding the Conversion Routes of Butanol in Steam Reforming Over Ni_x/MgO Catalyst.

Area of Science:

• Catalysis
• Chemical Engineering
• Materials Science

Background:

• Butanol steam reforming (BSR) is a promising route for hydrogen production.
• Understanding the reaction mechanism and the role of catalyst properties is crucial for optimizing BSR.

Purpose of the Study:

• To propose a detailed reaction scheme for BSR over mesoporous Ni/MgO catalysts.
• To investigate the effect of nickel (Ni) nanoparticle size on BSR performance.
• To correlate catalyst properties with hydrogen yield.

Main Methods:

• Synthesis of mesoporous Ni/MgO catalysts with varying Ni sizes (2.5–14.0 nm).
• Characterization using Temperature Programmed Desorption (TPD), Temperature Programmed Surface Reaction (TPSR), and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS).
• Evaluation of catalytic activity in BSR, focusing on hydrogen (H$_{2}$) yield.

Main Results:

• A two-pathway reaction mechanism for BSR was elucidated, involving butoxy and butyraldehyde intermediates.
• Catalyst performance was found to be dependent on the geometric configuration and electronic properties of Ni active sites.
• Ni$_{0.12}$/MgO, with an optimal Ni nanoparticle size of approximately 5.3 nm, exhibited the highest H$_{2}$ yield compared to catalysts with smaller or larger Ni sizes.

Conclusions:

• The study provides a comprehensive understanding of the BSR reaction mechanism over Ni/MgO.
• Nickel nanoparticle size is a critical factor influencing BSR activity and selectivity.
• Optimized Ni nanoparticle size (∼5.3 nm) on Ni$_{0.12}$/MgO maximizes hydrogen production via BSR.