Carbon nitride (g-C3N4) has attracted great attention for its wide applications in hydrogen evolution and photocatalytic degradation. In this study, phosphorus doped porous ultrathin carbon nitride nanosheets (PCN-S) were prepared successfully via the element doping and thermal exfoliation method. The prepared PCN-S was characterized by XRD, SEM, TEM, N2-adsorption-desorption measurement, FT-IR, XPS, UV–vis diffuse reflectance spectra, photoluminescence (PL), photocurrent response (I-t) and EIS. The results show that PCN-S owns regular crystal structure of g-C3N4, large specific surface areas and nanosheet structure with lots of in-plane pores on its surface, excellent chemical stability, and broad light response to the whole visible light region, which was attributed to the doping of phosphorus element. Under visible light irradiation, the photocatalytic reduction of Cr(VI) over different samples indicated that the P doping and porous nanosheet structure play an important role for the enhanced performance of PCN-S. The reason was that P element doping can broaden the visible light response region, and large specific surface areas from the porous nanosheet structure can provide quantities of active sites for the photocatalytic reaction. Then the detailed study on the PCN-S for simultaneous photocatalytic reduction of Cr(VI) and oxidation of 2,4-diclorophenol (2,4-DCP) was conducted. The experiments results show that low pH value and enough dissolved oxygen were found to promote Cr(VI) reduction and 2,4-DCP oxidation. The detailed photocatalytic mechanism was proposed. The strategies used in this study could provide new insight into the design of g-C3N4 based materials with high photocatalytic activity, and present potential for the treatment of Cr(VI)/2,4-DCP or other mixed pollutants in wastewater.

Insight into highly efficient simultaneous photocatalytic removal of Cr(VI) and 2,4-diclorophenol under visible light irradiation by phosphorus doped porous ultrathin g-C3N4 nanosheets from aqueous media: Performance and reaction mechanism

Surface Defect Engineering in 2D Nanomaterials for Photocatalysis

As a sustainable technology, semiconductor photocatalysis has attracted considerable interest in the past several decades owing to the potential to relieve or resolve energy and environmental-pollution issues. By virtue of their unique structural and electronic properties, emerging ultrathin 2D materials with appropriate band structure show enormous potential to achieve efficient photocatalytic performance. Here, the state-of-the-art progress on ultrathin 2D photocatalysts is reviewed and a critical appraisal of the classification, controllable synthesis, and formation mechanism of ultrathin 2D photocatalysts is presented. Then, different strategies to tailor the electronic structure of ultrathin 2D photocatalysts are summarized, including component tuning, thickness tuning, doping, and defect engineering. Hybridization with the introduction of a foreign component and maintaining the ultrathin 2D structure is presented to further boost the photocatalytic performance, such as quantum dots/2D materials, single atoms/2D materials, molecular/2D materials, and 2D–2D stacking materials. More importantly, the advancement of versatile photocatalytic applications of ultrathin 2D photocatalysts in the fields of water oxidation, hydrogen evolution, CO2 reduction, nitrogen fixation, organic syntheses, and removal pollutants is discussed. Finally, the future opportunities and challenges regarding ultrathin 2D photocatalysts to bring about new opportunities for future research in the field of photocatalysis are also presented.

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Ultrathin 2D Photocatalysts: Electronic-Structure Tailoring, Hybridization, and Applications.

Nanoscale Bi-based photocatalysts are promising candidates for visible-light-driven photocatalytic environmental remediation and energy conversion. However, the performance of bulk bismuthal semiconductors is unsatisfactory. Increasing efforts have been focused on enhancing the performance of this photocatalyst family. Many studies have reported on component adjustment, morphology control, heterojunction construction, and surface modification. Herein, recent topics in these fields, including doping, changing stoichiometry, solid solutions, ultrathin nanosheets, hierarchical and hollow architectures, conventional heterojunctions, direct Z-scheme junctions, and surface modification of conductive materials and semiconductors, are reviewed. The progress in the enhancement mechanism involving light absorption, band structure tailoring, and separation and utilization of excited carriers, is also introduced. The challenges and tendencies in the studies of nanoscale Bi-based photocatalysts are discussed and summarized.

Review on nanoscale Bi-based photocatalysts

g-C3N4界面改性:掺杂金属硫化物构建新型异质结光催化剂的能源转换展望

Novel nitrogen-doped carbon quantum dots (N-CQDs)/BiOBr ultrathin nanosheets photocatalysts have been prepared via reactable ionic liquid assisted solvothermal process. The one-step formation mechanism of the N-CQDs/BiOBr ultrathin nanosheets was based on the initial formation of strong coupling between the ionic liquid and N-CQDs as well as subsequently result in tight junctions between N-CQDs and BiOBr with homodisperse of N-CQDs. The photocatalytic activity of the as-prepared photocatalysts was evaluated by the degradation of different pollutants under visible light irradiation such as ciprofloxacin (CIP), rhodamine B (RhB), tetracycline hydrochloride (TC), and bisphenol A (BPA). The improved photocatalytic performance of N-CQDs/BiOBr materials was ascribed to the crucial role of N-CQDs, which worked as photocenter for light harvesting, charge separation center for separating the charge carriers, and active center for degrading the pollutants. After the modification of N-CQDs, the molecular oxygen acti...

Nitrogen-Doped Carbon Quantum Dots/BiOBr Ultrathin Nanosheets: In Situ Strong Coupling and Improved Molecular Oxygen Activation Ability under Visible Light Irradiation

Xiaowei Li

Papers

Nitrogen-Doped Carbon Quantum Dots/BiOBr Ultrathin Nanosheets: In Situ Strong Coupling and Improved Molecular Oxygen Activation Ability under Visible Light Irradiation

Constructing confined surface carbon defects in ultrathin graphitic carbon nitride for photocatalytic free radical manipulation

Taming wettability of lithium ion sieve via different TiO2 precursors for effective Li recovery from aqueous lithium resources

Synthesis of boron nitride nanosheets with N-defects for efficient tetracycline antibiotics adsorptive removal

Engineering a tandem leaching system for the highly selective recycling of valuable metals from spent Li-ion batteries