Poly(ionic liquid)-derived metal-free heteroatom co-doped porous carbons with peroxidase-like activity

Development of affordable, efficient and metal-free heterogeneous catalytic systems has been a persistent challenge in academia and industry. Heteroatom-doped metal-free carbon materials are increasingly recognized as valuable heterogeneous catalysts, and if well-designed, can present comparable performance to, or even surpass transition metal-containing catalysts. Their physicochemical properties and structural characteristics are tunable in a wide range, plus being free of leakage problems of transition metal species into the environment. Herein, three types of hierarchically porous N/X co-doped carbon materials (X denotes B, P or S) were synthesized via using poly(ionic liquid)s (PILs) as carbon precursors and source of heteroatom dopants. The incorporation of sacrificial pore-inducing templating agents which created abundant edge defects, in combination with a heteroatom co-doping strategy, enhanced the number of active sites and their peroxidase-like catalytic activities. Comparison with only nitrogen single-doped porous carbons as reference demonstrated that co-doping with nitrogen and another heteroatom exhibits higher peroxidase-like activity and affinity towards substrates. Among the three types of heteroatom co-doped porous carbonaceous artificial enzymes, the N/B co-doped carbonaceous catalyst displayed the highest specific activities and Vmax values. These observations suggest a synergistic effect of the co-dopants, here N and B in the enzyme that holds a promising potential to further enhance peroxidase-like activity.