Superhydrophobic Q10 Diluent Enabling Dehydration-Enhanced CO ₂ Hydrogenation and Active Phase Regulation

In CO2 hydrogenation over Fe-based catalysts, the reverse water–gas shift and Fischer–Tropsch synthesis represent the dominant reactions, generating hydrocarbons with water as a significant byproduct. The accumulation of water severely impairs catalytic performance by inhibiting forward reactions and oxidizing the active phase, thus reducing catalyst selectivity and stability. To selectively remove water from the reaction system, we synthesized a series of Q10 (SiO2 with 10 nm pore size) with a tunable water contact angle (15.8° to 154.3°) through a silanization method, and physically mixed with catalysts and act as functional diluents. The superhydrophobic SiO2 increased CO2 conversion from 25.2% to 38.7%, and selectivity of long-chain linear α-olefins (LAOs) from 21.4% to 38.9%, and the olefins selectivity in C2+ products reached as high as 73.8%. Furthermore, this hydrophobic system retained stable performance under multiple steam treatment conditions, which was attributed to its efficient water removal capability that drives the reaction forward and facilitates the formation of the active phase.