Sustainable Synthesis of P‐Doped Carbon Nitride From Fertilizer Sources for Enhanced Photocatalysis

The contamination of rivers, lakes, and oceans by synthetic toxic dyes has become a critical issue that is undermining water safety around the globe. Metal‐free semiconductors, and in particular the family of carbon nitrides, represent an appealing solution to degrade pollutants triggered by solar light illumination. Here, we present a new fabrication strategy for phosphorus‐doped carbon nitride starting from two abundant fertilizers widely used in agriculture: thiourea and diammonium phosphate. We show that in the resulting P‐doped carbon nitride P is incorporated by substitution of C atoms in the lattice, eventually increasing the population of photoexcited states and efficiently suppressing charge‐carrier recombination. Doped samples, and specifically the one obtained with an initial 1 %wt of P dopant in the precursor, demonstrate superior abilities in the degradation of four persistent dyes (Rhodamine B, malachite green, indigo carmine, Congo red) compared to the pristine carbon nitride. This P‐doped semiconductor efficiently catalyzes the quantitative photodegradation of common dyes in less than 60 min, thus proving noteworthy versatility and applicability for use in environmental remediation applications.