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[Display omitted] In the present study, an innovative carbon self-doped g-C 3 N 4 (CCN) loaded with ultra-low CeO 2 (0.067–0.74 wt%) composite photocatalyst is successfully synthesized via a facile one-pot hydrothermal and calcination method. The CeO 2 /CCN exhibits superior photocatalytic performance for tetracycline degradation (78.9% within 60 min), H 2 O 2 production (151.92 μmol L-1 within 60 min), and Cr(VI) reduction (99.5% within 40 min), which much higher than that of g-C 3 N 4 , CCN, CeO 2 , and CeO 2 /g-C 3 N 4. The enhanced photocatalytic performance is originated from the fact that the doping of C can efficaciously broaden the utilization range of solar light and improve the reduction ability of photogenerated electrons. Meanwhile, the ultra-low loading of CeO 2 can effectually promote the migration of photogenerated electrons and enhance the specific surface area. Besides, the experiments of pH effect and cycle ability indicate that CeO 2 /CCN has excellent durability and stability. Finally, the photocatalytic mechanism of CeO 2 /CCN is systematically discussed. This work proves that combining element doping and semiconductor coupling is a promising strategy to design high-efficiency g-C 3 N 4 -based photocatalysts. [ABSTRACT FROM AUTHOR]

CeO 2 nanoparticles are successfully loaded on carbonate doped Bi 2 O 2 CO 3 (CBOC) nanosheets by a facile hydrothermal and low-temperature calcination method. CeO 2 /CBOC heterojunction shows significantly enhanced photocatalytic activity, when 35 mg of CeO 2 /CBOC photocatalyst is added to tetracycline (TC) solution (20 mg/L, 100 mL), about 79.5% TC is degraded within 90 min under visible light irradiation, which is much higher than that of original CeO 2 and CBOC. According to photoelectrochemical characterization and active radical capture experiments, the Z-scheme electron transfer mechanism is the reason for the significant enhancement of photocatalytic activity. Besides, the XPS results indicate that Ce4+/Ce3+ redox pairs are formed at the contact interface between CeO 2 and CBOC, which is conducive to the transfer of photoexcited electrons and production of superoxide radicals. Additionally, the photocatalytic mechanism and possible degradation pathway of TC is proposed through free radical trapping experiments and liquid chromatography-mass (LC-MS) analysis. This study will accumulate experience for the combination of CeO 2 and bismuth-based nanomaterials, and provide a feasible way to design wide band-gap bismuth-based photocatalysts, thereby achieving efficient visible light degradation of environmental pollutants. [ABSTRACT FROM AUTHOR]

[Display omitted] • Coordinative Fe-N x improved the catalytic ability of FeOCN for photo-Fenton process. • The consumption of H 2 O 2 was reduced in the photo-Fenton process over FeOCN. • FeOCN showed high catalytic performance for tetracycline degradation. • The improved charge separation favored Fe(III)/Fe(II) conversion. • FeOCN exhibited wide applicable pH range and anti-interference ability to anions. Tetracycline (TC) antibiotics have been widely used over the past decades, and their massive discharge led to serious water pollution. Photo-Fenton process has gained ever-increasing attention for its excellent oxidizing ability and friendly solar energy utilization ability in TC polluted water treatment. This work introduced coordinative Fe into oxygen-enriched graphite carbon nitride (OCN) to form FeOCN composites for efficient photo-Fenton process. Hemin was chosen as the source to provide the source of coordinative Fe-N x groups. The degradation efficiency of TC reached 82.1 % within 40 min of irradiation, and remained 76.9 % after five runs of reaction. The degradation intermediates of TC were detected and the possible degradation pathways were gained. It was found that h+, OH, and O 2 − played major roles in TC degradation. Notably, the photo-Fenton performance of FeOCN was stable in highly saline water or strong acid/base environment (pH 3.0–9.0). Besides, H 2 O 2 can be generated in-situ in this photo-Fenton process, which is favorable for practical application. It can be anticipated that the coordinative FeOCN composites will promote the application of photo-Fenton oxidation process in TC polluted water treatment. [ABSTRACT FROM AUTHOR]

At present, environmental pollution caused by refractory organic pollutants becomes more serious. Semiconductor-based photocatalysis technology, an idea and continuable technology by solar-light-driven, is widely employed to address this situation. Here, oxygen-vacancy rich WO 3 decorated monolayer Bi 2 WO 6 nanosheet composite as an atomic scale heterojunction with high active species and ultrafast charge carrier transfer was rationally constructed. The atomic scale V o -WO 3 /Bi 2 WO 6 composite displayed remarkable photoactivity comparing with pristine V o -WO 3 and Bi 2 WO 6 ultrathin nanosheet, and about 79.5% of Ciprofloxacin can be degraded within 120 min under visible light irradiation when 40 mg of photocatalyst was added into CIP solution (10 mg/L). The promoted photoactivity can be ascribed to the following points: (1) the composite possesses enormous surface pit, thereby expanding the species surface area and exposing more active site to promote antibiotic absorption; (2) the presence of abundant oxygen vacancy can facilitate the formation of more electrons, which can be consumed by adsorbed molecular oxygen to produce superoxide radical, thereby accelerating degradation organic pollutant; (3) ultrathin V o -WO 3 nanosheet decorated monolayer Bi 2 WO 6 can shorten the charge carrier transfer distance and enlarge interface contact area, then ensuring remarkable photodegradation efficiency. The reasons for promoted photodegradation efficiency were elaborated based on experiments results and ESR analysis and the degradation pathways of CIP were recorded via [(LC-MS)/MS]. After 5 run for the degradation of CIP, V o -WO 3 /Bi 2 WO 6 composite also exhibited great photodegradation efficiency, thereby demonstrating its excellent stability and reusability. [ABSTRACT FROM AUTHOR]