Surface chemistry engineering via phytic acid doping: Tailoring activated carbons for selective catalysis

Phytic acid (PA) is a renewable and efficient phosphorus precursor for synthesizing P-doped activated carbons, offering advantages such as ease of handling and the ability to introduce defined surface functionalities. However, the role of PA as a direct dopant and the influence of synthesis parameters on the resulting materials' structure and performance have not been sufficiently explored. In this study, a commercial porous carbon (RGC-30) was doped with PA using a strategy that combines mild pre-treatment and pyrolysis at temperatures ranging from 650 to 950 °C. Comprehensive characterization reveals that phosphorus speciation is highly dependent on synthesis conditions. Oxidized P groups form at lower temperatures, while pre-treatment combined with higher pyrolysis temperatures favors reduced species such as C 3 PO and C 3 P. Catalytic testing in two model reactions—benzyl alcohol oxidation and hydrogenation of 1-chloro-4-nitrobenzene—demonstrates that C 3 PO groups are highly active and stable in oxidation, while C 3 P species enhance hydrogenation activity but gradually convert into C 3 PO over time. These findings highlight the tunability of PA-derived P-doped carbons and establish a clear structure–activity relationship, where surface speciation, rather than total P content, governs catalytic behavior. This work positions phytic acid as a green and scalable dopant for designing robust, metal-free catalysts for selective transformations.