Unraveling the Synergy Mechanism between Photocatalysis and Peroxymonosulfate Activation on a Co/Fe Bimetal-Doped Carbon Nitride

Abstract

Fenton-like catalysis based on peroxymonosulfate (PMS) activation has shown great potential in the treatment of organic wastewater. Heterogeneous Fenton-like catalysts containing transition metal active sites are highly efficient for PMS activation. However, the reduction of oxidized metal active sites was usually not prompt due to the sluggish reaction kinetics, which caused the insufficient redox cycle of the metal active sites and further hampered the catalysis efficiency. Recent studies have shown that the synergy effect between photocatalysis and PMS activation may address the above obstacle and boost overall efficiency. However, a deeper understanding of this synergy effect is still missing, making it difficult to be rationally controlled; thus, a poor synergy effect is frequently reported. Herein, a Co/Fe bimetal-doped graphitic carbon nitride (g-C 3 N 4 ) was designed representatively through systematical characterization and theoretical calculation, the synergy effect was revealed to be profoundly determined by the competitive role of a hole in the system and the adsorbed metastable PMS* on the catalyst surface, and furthermore, the synergy effect can be rationally manipulated; when the Co/Fe doping ratio is 2.5:2.5, the as-prepared g-C 3 N 4 with a moderate valence band position can endow the catalyst with an optimized photo-Fenton-like synergistic effect and the highest catalytic degradation performance. This work sheds light on the rational design of highly efficient photo-Fenton-like catalysts.

Dual-defect semiconductor photocatalysts for solar-to-chemical conversion: advances and challenges

“…For compound semiconductors, the CBM is generally made of orbitals of cations; therefore, dual-cationic co-doping will lead to a dramatic influence on the electronic band structures of semiconductors. [74][75][76] Meanwhile, co-doping has a heavy effect on the periodicity and stability of crystals, resulting in the easy escape of native anions. 77 In addition, cationic sites usually act as catalytic active sites; the large change in cation composition may result in the alternation of catalytic sites.…”

Z-Scheme Heterojunction α-Fe2O3/Tubular g-C3N4 with C Defects for Photocatalytic Degradation of Microcystin-LR in Water: Generation and Effect of Critical Species 1O2

“…The different ROS generated in the reaction system can be characterized using a capture agent in principle . 10 mM of methanol (MeOH) and tert -butanol (TBA), 10 mM of furfuryl alcohol (FFA), 10 mM of l -ascorbic acid ( l -AA), and 10 mM of ethylenediaminetetraacetic acid disodium salt (EDTA·2Na) were used for capturing • OH, 1 O 2 , • O 2 – , and h + , respectively (Figure a). , It can be observed that the effects of adding two different • OH trapping agents (MeOH, TBA) on the reaction system were fragile, which represents a small role in removing • OH from the system. The degradation rate of MC-LR decreased by 64.41% after the addition of FFA, which was significantly inhibited, representing that 1 O 2 played a crucial role in MC-LR degradation.…”

Photo‐self‐Fenton Reaction Mediated by Atomically Dispersed Ag−Co Photocatalysts toward Efficient Degradation of Organic Pollutants

“…Single‐atom catalysts (SACs) with the maximization of the atoms in supported catalysts are emerging as a promising filed in heterogeneous catalysis, which have many applications for CO 2 reduction, [5] hydrogen evolution, [6a–b] methane oxidation, [7] degradation of the wastewater [8] and many other fields [9] . Particularly, among the supported hosts, the graphitic carbon nitride (g‐C 3 N 4 ), a typical polymer semiconductor as a visible‐light‐responsive photocatalyst, has attracted much attention in various fields such as environmental and energy catalysis [10a–c] . In addition, the electron‐rich N elements in g‐C 3 N 4 can easily form the M−N x structures by the coordination with metal elements, which can form the single‐atom metal active sites with excellent stability, thus blocking their self‐gathering and leaching of the metal elements.…”