Deciphering proximal effects in substituted carbon nanozymes: Modulating ROS recognition and enhancing catalytic activity

Proximal effects between functional groups in substituted carbon nanozymes can influence their activity towards reactive oxygen species (ROS). However, their molecular-level understanding remains limited, restricting full utilization. Herein, we combine molecular dynamics and quantum mechanics calculations to reveal how proximal functional group effects regulate ROS recognition and catalytic activity. The results demonstrate that each isolated functional group can provide a limited thermodynamically favorable region for ROS recognition, within which the binding strength can overcome the diffusion trends of ROS. The strongest ROS binding occurs when the -COO - group binds to H 2 O 2 ; however, H 2 O 2 enrichment is limited to within ∼12 Å, beyond which H 2 O 2 tends to diffuse away. Other ROS exhibit even weaker binding affinities and smaller recognition ranges, from 4 to 8 Å. Thus, proximity groups may regulate ROS recognition through steric hindrance, competitive binding, and cooperativity, while also inducing intramolecular hydrogen bonding that can either hinder or enhance ROS binding. QM calculations focus on the activity of -OH substituted nanozymes toward H 2 O 2 . Positioning -OH groups on rings with a single exposed C–H site results in higher activity than placement on rings with three exposed C–H sites, while appropriate positioning of additional proximal -OH groups further promotes H 2 O 2 activation, lowering the activation energy by 3.2 and 2.4 kcal/mol, respectively. These results indicate that designing nanozymes with synergistic proximal effects between functional groups is promising for enhancing their activity.