Rich and Stable Interlayer Porous Bamboo Carbon Sulfonic Acids Constructed by Silica Intercalation as Cheap and Robust Acid Catalysts

The rich and stable interlayer porous biomass carbon sulfonic acids (SBCSAs) pillared by silica were prepared conveniently using bamboo powder and water glass as main raw materials and investigated by a series of characterization techniques. Additionally, the acid catalysis performances of SBCSAs were evaluated using the hydrolysis of sucrose, the esterification of oleic acid with methanol and the alkylation of toluene with benzyl chloride. The results showed that 0.05–0.025 M acidic silica sols could be efficiently and uniformly intercalated into the interlayers between bamboo carbon (BC) nanosheets, yielding the silica-pillared BC materials (SBCs) with rich interlayer slit-like pores after dehydration at 350 °C. Moreover, the porosity of SBCs could be very well kept after further sulfonation with concentrated sulfuric acid. The newly constructed SBCSA materials exhibited higher catalysis efficiency and better reusability for the above acid-catalyzed reactions than the non-pillared BCSA and commercial Amberlyst-15, which should be due to the overall improvements relating to their structure, porosity and acidity, as supported by BET, TGA, STEM-EDS and solid-state 31P MAS NMR spectra of adsorbed TMPO. This work opens up a new voyage for the fabrication of porous bio-based solid acids with good catalysis properties and extensive application prospect.