Exploring the selectivity of renewable phenol from catalytic pyrolysis of biomass via activated carbon catalyst

Due to incomplete hydrodeoxygenation, common biofuels, for examples alcohol-ether oxygenated fuels, is prone to oxidation in air and deviates its combustion efficiency and emissions profile. Phenolic antioxidants can substantially raise the oxidative stability of biofuels via the tapping of peroxy radicals. Activated carbon (AC) emerges as efficient catalysts for selective phenol production, even without any surface modification or metals loading. However, it’s still difficult to detect solo contributions of pore channel and native active sites in AC catalysts during reactions, due to their evolution are coupled when preparation. Herein, an ingenious experiment was designed to decouple their contributions via the comparison of three representative AC catalysts, where K-AC and Z-AC possess parallel pore size distribution (average pore size of 1.896 nm vs. 1.837 nm), while Z-AC and P-AC possess parallel acidic active sites. Results tend to the truth that phenol selectivity seems mainly dependent on active sites, where the acidic active site is more efficient than the basic, while little relevant with acidity strength. P-AC and Z-AC showed similar phenol selectivity (67.24 % vs. 65.52 %). Additionally, pore size distribution that performed the role of “shape-selective catalysis” seems mainly contribute to phenol yield, rather than phenol selectivity. So that, the phenol yield in P-AC is almost one-sixth more than Z-AC. Overall, this study provides a promising approach to interpret the mechanism of ACs in catalysis or other high value applications.