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The effective activation of peroxymonosulfate (PMS) by polymer carbon nitride (PCN) is hampered by the unpredictable movement and rapid recombination of photocarriers. In this study, niacin served as a beneficial modifier to help constructed the directional electron transfer pathway from the center to the edge in the synthesized PCN catalyst (UCNNA) for efficient PMS activation. The UCNNA/PMS/vis shows the highest kinetic constants (0.050 min−1), which is 2.9-fold increase over the PCN/PMS/vis. The experiments and theoretical calculations indicated that niacin as electron acceptor group prevents the recombination of photocarriers in-plane. Simultaneously, niacin can serve as PMS adsorption site, further facilitating electron transfer and the 1O 2 generation. Mass spectrometry analysis and Fukui index calculations confirm the priority of lateral chain oxidation (1O 2 attack site) during atrazine degradation. These results provide new insights into rational design of metal-free catalysts/PMS/vis system, as well as providing guidance and theoretical support for atrazine degradation mechanisms. [Display omitted] • The electron acceptor grafted PCN has been constructed by facile one-step thermopolymerization. • The electron acceptor nicotinic acid groups server as adsorption sites for PMS. • Electron transfer and 1O 2 in this system facilitate efficient degradation of ATZ. • The UCNNA/PMS/vis system has strong anti-interference ability. • The side chain of ATZ is preferentially attacked in this system. [ABSTRACT FROM AUTHOR]

Herein, sulfur and sodium co-doped cyano-rich polymeric carbon nitride (NaCNS) have been designed to boost photocatalytic atrazine (ATZ) degradation with peroxymonosulfate (PMS) assistance. The NaCNS was fabricated via a two-step thermal condensation with the existence of sodium chloride and cysteine, and the ATZ degradation in the system was evaluated via batch experiments. Compared to pristine carbon nitride, the reaction rate constant of NaCNS was dramatically enhanced nearly sixfold (47.66 ×10−3·min−1). Given the experiments and theoretical calculation, the ATZ degradation in the system was mainly dominated by the electrophilic attack of O 2 1 , leading to the production of 11 intermediates with reduced ecotoxicity. The promoted photocatalytic performance was originating from the dual modulation of NaCNS, where the sodium act as a PMS activation site while the cyano and sulfur construct an electronic push-pull system for better photocarrier separation. Hopefully, this study can inspire the rational design of catalysts for efficient photocatalytic PMS activation. [Display omitted] • Dual modulation of PCN was achieved for photocatalytic PMS activation. • S and cyano group promoted charge separation via an electronic pull-push system. • Na boosted the mass transfer from catalyst to PMS for a reduced energy barrier. • ATZ can be effectively degraded with various influences of environmental factors. • Degradation of ATZ in this system can effectively reduce its ecological hazard. [ABSTRACT FROM AUTHOR]

• Triazole and pyromellitic diimide modified carbon nitride (TACP) was fabricated; • The thin-walled vesicular TACP can effectively enhance the n → π* electron excitation; • The donor-π-acceptor electron structured TACP promoted the separation of photocarriers; • TACP significantly enhanced the photodegradation of atrazine to a 95% removal rate; • Two pathways and 14 intermediates were proposed during atrazine degradation in the system. Polymeric carbon nitride (PCN) as a competitive non-metal photocatalyst, has been widely applied in water treatment. However, the limited visible-light utilization and high photocarrier recombination rate restrict its photocatalytic efficiency. Herein, triazole and pyromellitic diimide were applied for the bimolecular decoration of polymeric carbon nitride (PCN) to fabricate TA-CN-PDI for the photodegradation of atrazine. The thin-walled vesicular morphology in TA-CN-PDI can enhance the n→π* electron excitation, and the donor-π-acceptor electronic structure can promote the directional movement of photogenerated electrons and holes. The theoretical and experimental results suggested that the vesicular structure and the donor-π-acceptor electronic structure synergistically promoted the photoactivity of the catalyst. Compared to the pristine PCN, the reaction rate constants of atrazine by TA-CN-PDI increased to 6.64-fold, achieving a 95 % removal rate. It was found that 1 O 2 , OH , h + , · O 2 - were contributed to the ATZ degradation. In addition, mainly 14 intermediates and two pathways were proposed according to the LC-MS analysis. Hopefully, this modification strategy of PCN and its application in ATZ degradation can pave a way for subsequent research on the modification of photocatalysts. [ABSTRACT FROM AUTHOR]

In this study, a novel S-scheme Ni-doped β-Bi 2 O 3 /ACN heterojunction with superior enhanced photoactivity was successfully prepared via two-step methods. The degradation efficiency of target pollutant ciprofloxacin (CIP) by the 7%Ni-doped β-Bi 2 O 3 /3%ACN composite (3A@BN7) within 1 ​h is as high as 95.93%, which is 5.54 times than β-Bi 2 O 3 and 2.83 times than ACN. Moreover, the heterojunction composites synthesized in this work exhibited extraordinary removal effects on various pollutants. Meanwhile, the 3A@BN7 composites possess the ability to evolution hydrogen under visible-light irradiation with an efficiency reached 3099.1 ​μmol H 2 within 4 ​h, while the pure β-Bi 2 O 3 does not show any hydrogen evolution capability. The characterization results manifest that the enhancement of the photocatalytic activity of the heterojunction composites is attributed to more abundant reactive sites, higher utilization rate of visible light, lower interfacial charge transfer resistance than pure β-Bi 2 O 3. Staggered energy level structure of the composites cooperating with Ni doping led to lower recombination rate of hole-electron pairs and narrower band-gap are also reflected in improved photoactivity. A possible mechanism of the S-scheme heterojunction for the enhancing photocatalytic activity is proposed combined with the results of all characterization and experiments. This work puts forward a novel heterostructure constructing method for β-Bi 2 O 3 , which may provide a reference for application in industrial removal of organic pollution from water due to its excellent stability and wide selectivity. The flower-like Ni -doped β-Bi 2 O 3 /ACN microsphere composite was successfully prepared through the solvothermal method, the composite shows high improvement of photocatalytic activity and stability for antibiotics CIP degradation and H 2 evolution under simulated sunlight irradiation. [Display omitted] • The flower-like Ni -doped β-Bi 2 O 3 /ACN microspheres is successfully synthesized. • The Ni -doped β-Bi 2 O 3 /ACN microspheres shows superior activity for CIP degradation. • The charge transfer rate and redox ability of charge carriers are greatly improved. • The possible mechanism of the S-scheme heterojunction is proposed and discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] • PDI-g-C 3 N 4 /g-C 3 N 4 (CPH) has been fabricated via multiscale modification strategy. • CPH exhibited excellent photocatalytic atrazine removal efficiency. • The mesoporous morphology of CPH enhanced the accessibility of contaminant. • The PDI decoration of CPH promoted light-harvesting and π-conjugation. • The construction of homojunction suppressed the recombination of photocarrier. Herein, PDI-g-C 3 N 4 /g-C 3 N 4 homojunction has been fabricated via the multiscale modification strategy to enhance photocatalytic atrazine degradation. The morphological scale modification was realized by multistep thermal condensation, where the released gas could act as templates to form the porous structure. The molecular scale modification was achieved by the pyromellitic diimide (PDI) decoration, which could distort the planar nanosheet to induce a porous structure and provide more chromophores for better light absorption. The electronic scale modification was realized by the built-in electric field between the PDI-g-C 3 N 4 /g-C 3 N 4 homojunction interfaces, which suppressed the recombination of photocarriers. The PDI-g-C 3 N 4 /g-C 3 N 4 strengthened photocatalytic atrazine degradation was well-adapted to different environmental influence interference. The optimum atrazine degradation rate within one hour reached 90% in a strong acidic condition (pH = 3.09). It was found that the highly pH-dependent ATZ removal is related to the H 2 O 2 generation during photocatalysis. Within one hour, the PDI-g-C 3 N 4 /g-C 3 N 4 could generate 147.38 μM H 2 O 2. In addition, 1 O 2 ,  · O 2 - , h+, and  · O H were found to have contributed to the ATZ decomposition. During photocatalysis, 14 intermediates and three pathways for atrazine degradation have been found. Hopefully, this study could pave a way for the development of the multiscale modification for the photocatalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • PDI-g-C 3 N 4 /g-C 3 N 4 (CPH) has been fabricated via multiscale modification strategy. • CPH exhibited excellent photocatalytic atrazine removal efficiency. • The mesoporous morphology of CPH enhanced the accessibility of contaminant. • The PDI decoration of CPH promoted light-harvesting and π-conjugation. • The construction of homojunction suppressed the recombination of photocarrier. Herein, PDI-g-C 3 N 4 /g-C 3 N 4 homojunction has been fabricated via the multiscale modification strategy to enhance photocatalytic atrazine degradation. The morphological scale modification was realized by multistep thermal condensation, where the released gas could act as templates to form the porous structure. The molecular scale modification was achieved by the pyromellitic diimide (PDI) decoration, which could distort the planar nanosheet to induce a porous structure and provide more chromophores for better light absorption. The electronic scale modification was realized by the built-in electric field between the PDI-g-C 3 N 4 /g-C 3 N 4 homojunction interfaces, which suppressed the recombination of photocarriers. The PDI-g-C 3 N 4 /g-C 3 N 4 strengthened photocatalytic atrazine degradation was well-adapted to different environmental influence interference. The optimum atrazine degradation rate within one hour reached 90% in a strong acidic condition (pH = 3.09). It was found that the highly pH-dependent ATZ removal is related to the H 2 O 2 generation during photocatalysis. Within one hour, the PDI-g-C 3 N 4 /g-C 3 N 4 could generate 147.38 μM H 2 O 2. In addition, 1 O 2 ,  · O 2 - , h+, and  · O H were found to have contributed to the ATZ decomposition. During photocatalysis, 14 intermediates and three pathways for atrazine degradation have been found. Hopefully, this study could pave a way for the development of the multiscale modification for the photocatalyst. [ABSTRACT FROM AUTHOR]