Tailoring phenol photomineralization pathway over polymeric carbon nitride with cyano group multifunctional active sites

[Display omitted] •Solving phenol polymerization problem by tailoring H2O2 formation and transformation via CN modification.•Improved charge separation and subsequent in-situ decomposition of H2O2 to OH due to phenol adsorption.•In-situ IR spetrascopy as a powerful tool to investigate the active sites and surface reaction pathway for phenol photodegradation. The electronic and interfacial properties of catalysts play vital roles in tailoring catalytic performance. Here, we report that the modification of polymeric carbon nitride (PCN) with cyano group (CN) can achieve excellent catalytic performance in mineralization of phenol. The CN site not only enhances the adsorption and activation of molecular O2 for efficient H2O2 production, but also improves the absorption capability of PCN for phenol in aqueous solution by tuning surface charge states. Subsequently, the surficial adsorbed phenol acts as holes scavenger which promotes the separation efficiency of photogenerated carriers in PCN and in turn facilitates the in-situ decomposition of H2O2 to OH. This reduces the uncontrollable decomposition of H2O2 to OH and inhibits the polymerization of phenolic compounds. The active sites of catalyst, O2 transformation state and pathway on the catalyst surface as well as the firstly attacked sites of phenol are confirmed respectively by in-situ DRIFT spectra, scavengers and Bader charge analysis.