The photocatalytic selective oxygen reduction reaction on a polymeric carbon nitride framework is one of the most promising approaches toward sustainable H2O2 production. Potassium poly­(heptazine imide) (K-PHI) was highly active for photocatalytic H2O2 production. Most importantly, by introducing 1-methyl-1H-tetrazole-5-thiol (MTT) into the precursor for the K-PHI synthesis, the size of the layer stacking structure was reduced, the polymerization in the heptazine plane was improved, and the conduction band position was negatively shifted. The MTT-regulated K-PHI (K-PHI-2) showed remarkable H2O2 photoproduction performance, for example, a record high H2O2 photoproduction rate of 41.7 μmol h–1 mg–1 in an acidic environment. Meanwhile, K-PHI-2 showed a significantly enhanced performance in the photocatalytic degradation of the carbamazepine. Additionally, by introducing 5 ppm O3 in the reaction system, ciprofloxacin at a concentration of 100 ppm was eliminated rapidly on K-PHI-2 via a peroxone reaction.

A highly efficient mediated-electron transfer process of PMS activation on Co was achieved by construction of a spatially-confined reaction environment.

Efficient approaches toward selective removal of the emerging organic pollutants are of critical importance to the well-being of the human health and the eco-system. Peroxymonosulfate-involved advanced oxidation process is promising in water treatment due to a couple of intrinsic advantages of the reaction system, and the development of an efficient catalyst is essential to the real application of this technique. In this work, a series of single-atom Fe catalysts were fabricated via a facile method, and the single-atom center was identified to be in a Fe–N4 configuration by Fe K-edge X-ray absorption spectroscopy. On the optimum catalyst with 4.8 wt % Fe single atom, 22 ppm BPA could be eliminated within 40 s under mild reaction conditions, affording a remarkable pseudo-first-order reaction rate constant of 8.4 min–1. The durability of the catalyst was tested with a fixed-bed flow reactor, and 55.2 L of polluted water with 10 ppm BPA could be treated with a removal rate of >95% by 1 g of catalyst. Through a series of probe reactions and spectroscopic analysis, the mediated electron-transfer mechanism was identified to be dominant during the pollutant degradation process.

Catalytic activation of peroxymonosulfate is one of the most promising advanced oxidation processes for water treatment. The development of advanced functional catalysts is essential to efficient and selective elimination of the emerging organic pollutants in water. Via a facile one-step method using the naturally abundant tannic acid and low-cost melamine as precursors, the atomically dispersed Fe was anchored on a nitrogen-doped carbon matrix, and the configuration of Fe-N 4 was confirmed by synchrotron X-ray absorption spectroscopy. The singleatom Fe catalyst was efficient in catalytic degradation of various organic pollutants, e.g., removal of 100 μM BPA within 40 s under mild reaction conditions. The essential role of high-valent iron-oxo species in selective degradation of pollutants was identified by systematic mechanistic investigations. This work demonstrates the unique advantages of high-valent Fe IV =O in selective elimination of emerging organic pollutants and sheds light on the design of an efficient and durable single-atom catalyst for a variety of applications.

In a nanoconfined space, the chemical/physical properties of molecules/ions can be fundamentally changed; the strategy of nanoconfinement thus offers rich opportunities for the development of an efficient catalytic process. Peroxymonosulfate (PMS) involved in advanced oxidation processes is a promising technology for efficient abatement of recalcitrant pollutants. Radical, singlet oxygen, and high-valent cobalt species are, hitherto, reckoned as the predominant reactive species for pollutant degradation in cobalt-catalyzed reaction systems. Herein, a distinctive mediated electron-transfer mechanism of cobalt was substantiated in a nanoconfined space. Moreover, an unusual pollutant-dependent PMS consumption behavior was revealed; the presence of pollutant unexpectedly attenuated the PMS consumption, which was contrary to the knowledge in the usual mediated electron-transfer mechanism of noble metals or carbon. By nanoconfinement regulation, the reaction system afforded an unprecedently efficient catalytic performance for pollutant degradation, for example, rapid elimination of bisphenol A and 2-chlorophenol with a high concentration of 100 ppm within 1 min and 40 s, respectively.