Synthesis and Physicochemical Characterization of Natural Sand-derived Mesoporous Silica Santa Barbara Amorphous 15 (SBA-15)

Abstract

The methane reforming technologies augmented with carbon capture, utilization, and storage are expected to play a transformative to achieve net zero carbon emissions by 2050. However, catalyst deactivation due to nanoparticle agglomeration and carbon deposition are major limiting factors in blue hydrogen production. The development of effective and highly stable catalysts is imperative for the cost-effective commercialization of these technologies. Anchoring active particles on supports is a common strategy to overcome the deactivation problem. However, commercial silica sources such as tetraethyl orthosilicate (TEOS) are used as precursors for support preparation. Herein, locally available natural sand was used as a precursor for the synthesis of mesoporous silica-based support material SBA-15. Silica was extracted from natural sand in the form of sodium silicate by NaOH fusion. The as-extracted sodium silicate was used to prepare SBA-15 using Pluronic P123 as a structure-directing agent. The sand-derived SBA-15 exhibited a large specific surface area of 615 m2 /g, with an average pore size of 7.45 nm, and a total pore volume of 1.07 cm3 /g. Physicochemical properties such as surface area, pore size, metal crystallite size, functional groups, and surface morphology of sand-derived SBA-15 were comparable to TEOS-derived SBA-15. Rod-like external surface morphology was obtained for SBA-15 obtained through both the silica sources i.e., TEOS and sand. Afterward, Ni and Co were anchored to natural sand-derived SBA-15 by co-precipitation method assisted by urea. The catalyst was evaluated for CO2 reforming of CH4. The Ni and Co bimetallic nanoparticles stabilized on sand-derived SBA-15 exhibited high CH4 and CO2 conversion indicated by 45% CO and 40% H2 in the product at 1:1 GHSV 20,000 mL.g-1 .h-1 , 700 °C, and 1 atm. The catalysts prepared by wet impregnation assisted by urea hydrolysis with additional washing before calcination exhibited higher CH4 conversion and stability than catalysts prepared by wet impregnation without urea hydrolysis and washing.

Date of Award	Aug 2023
Original language	American English
Supervisor	Cheng Kui (Supervisor)