The development of highly efficient photocatalysts is crucial to realize water remediation via photocatalysis technology. In this work, nitrogen-rich porous polymeric carbon nitride (DCCN-S) was prepared through calcining the intermediate...

Iron phthalocyanine/carbon nitride (FePc/CN) heterojunction nanosheets were prepared by a facile calcination strategy, which exhibited superior ability of peroxydisulfate (PDS) activation toward degradation of tetracycline (TC) assisted by visible light. The removal rate of high-concentration TC (50 mg L −1 ) over FePc/CN-6 reached 97% within 40 min, with the degradation rate constant of 4.4 and 9.2 times those of CN and FePc, respectively. The excellent catalytic performance of FePc/CN-6 could be attributed to the synergistic effect between photocatalysis and PDS activation. The construction of the FePc/CN-6 heterojunction with an intimate interface via π−π conjugation inhibited the aggregation of FePc, promoted charge separation and transfer, and broadened the response range of visible light. As a result, the highly dispersed Fe active sites as well as more available photogenerated electrons and holes enhanced the PDS activation and the photodegradation. EPR spin-trapping tests and radical quenching experiments confirmed the role of multiple active species in the TC removal. The effects of temperature, pH, coexisting anions, and water sources on the removal rate of TC were investigated. FePc/CN-6 also displayed good potential in actual wastewater treatment. This work not only provides insight into design and preparation of efficient and stable catalysts for PDS activation but also establishes a promising catalytic oxidation system for the green remediation of actual wastewater.

We present a facile bottom-up strategy to prepare crystalline polymeric carbon nitride (CCN) with ultrathin 2D nanosheet structures, which involves supramolecular self-assembly into crystalline rodlike intermediates and subsequent thermal-induced exfoliation and polycondensation. Under visible light irradiation, CCN can efficiently remove various high-concentration organic pollutants (50 mg L–1) and synergistically remove organic pollutants and heavy metal ions. The removal rates of all organic pollutants including antibiotics and dyes exceed 95% within 40 min, outperforming previously reported photocatalysts. Moreover, it also exhibits outstanding photocatalytic performance in the water-splitting reaction with a H2 evolution rate of 11.5 mmol g–1 h–1. The highly boosted activity of CCN can be attributed to the significantly improved charge separation, the increased accessible active sites, as well as the enhanced visible light absorption, benefiting from its high crystallinity and ultrathin 2D nanosheet structure. This work presents a feasible strategy for the preparation of crystalline carbon nitride nanosheets toward energy and environmental applications.