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Environmental pollution has become an imminent problem for the healthy and sustainable development of human society. Although photocatalytic degradation of organic pollutants over semiconductors was recognized as a promising strategy to resolve this problem, the degradation activity of most of photocatalysts was unsatisfactory owing to the rapid recombination of photogenerated electron-hole pairs. In this work, significantly enhanced degradation performance for RhB organic dye over graphite carbon nitride (g-C3N4) photocatalyst were demonstrated, resulting from the synergetic photocatalytic and piezocatalytic effects. The photocatalytic and piezocatalytic degradation properties of g-C3N4 photocatalyst and the influence of nitrogen defects on them were investigated respectively. With the synergetic functions of light irradiation and mechanical vibration, the synergistic degradation performance is significantly greater than the sum of single photocatalysis and piezocatalysis owing to the recombination of photogenerated carries could be inhibited effectively by the created piezoelectric field in g-C3N4 nanosheets. These findings proved that the coupling of photocatalytic and piezocatalytic properties of semiconductors opens a new gateway to remove organic contaminants. [ABSTRACT FROM AUTHOR]

In this work, Eu doped CaAlSiN red-emitting nitride phosphors were synthesized for the first time from less-expensive and air-stable entire oxides raw materials, CaCO, SiO, AlO, and EuO, through a common carbothermal reduction and nitridation (CTRN) method. The synthetic reaction processes involving in this CTRN route and the phase components, photoluminescent properties for the resultant CaAlSiN:Eu nitride phosphors were investigated in detail. The presented synthesis route using cost-effective entire oxides raw materials for preparation of CaAlSiN:Eu nitride phosphors shows promising prospect in promoting the application of CaAlSiN:Eu nitride phosphors in solid state lighting. [ABSTRACT FROM AUTHOR]

Carbon materials have attracted abundant attentions and been utilized widely as anodes in rechargeable Li+/Na+/K+ ions batteries. Regarding the various radius of alkali-metal-ions, reversible intercalation and deintercalation in interlayers of carbons requires different interplanar spacing. In this work, N-doped graphene with tunable interplanar spacing is synthesized using graphitic carbon nitride (g-C 3 N 4) as precursor with the assistance of polyvinylpyrrolidone (PVP). The obtained tunable interplanar spacing in the range from 0.34 nm to 0.45 nm with enlarged values is mainly ascribed to the high nitrogen doping levels (9.98–33.7 at. %), especially to the pyrrolic nitrogen. Serving as the anode materials in lithium ions batteries (LIBs) and sodium ions batteries (SIBs), promising specific capacities of 1236 mAh g−1 for LIBs and 300 mAh g−1 for SIBs at current density of 0.05 A g−1 and excellent cycling stability as well as acceptable rate capability are demonstrated for the resultant N-doped graphene. The influences of interplanar spacing on the electrochemical performances of LIBs and SIBs are investigated comparatively. This work outlines a facial route to synthesize N-doped graphene with tunable interplanar spacing, meeting the various requirements unitized as anodes in rechargeable Li+/Na+/K+ ions batteries. Tunable interplanar spacing N-doped graphene derived from graphitic carbon nitride (g-C 3 N 4) was synthesized with the assistance of polyvinylpyrrolidone (PVP), exhibiting promising electrochemical performances as lithium/sodium ions battery anodes. Image 1 [ABSTRACT FROM AUTHOR]

Fine control of nitrogen-doping in carbon materials is an urgent issue with great challenges for the applications in energy storage devices. In this work, nitrogen-doped hollow carbon spheres (NHCS) with tunable nitrogen-doping properties are synthesized by using graphitic carbon nitride (g-C 3 N 4) nanosheets as precursor and Zinc powder as the template. A series of characterization techniques were performed to evidence the successful transformation of NHCS from g-C 3 N 4. The nitrogen-doping level from 12.76 at.% to 27.82 at.% and the relative doping fractions of pyridinic-N, pyrrolic-N and graphitic-N for the g–C 3 N 4 –derived carbon materials can be easily tuned by controlling the synthetic temperatures. Serving as Li-ions battery anodes, the resultant NHCS delivers an acceptable initial discharge capacity of 1012.4 mAh g−1 under a current density of 0.1 A g−1 and a promising cycling stability (1064.5 mAh g−1 after 400 cycles) as well as an excellent rate performance (360 mAh g−1 at 10 A g−1). This work provides a facile gateway to synthesize high nitrogen-doped carbon materials applying to energy storage devices, from nitrogen-rich g-C 3 N 4 precursor. Image 1 [ABSTRACT FROM AUTHOR]

Vacancies engineering was widely reported as the promising strategy for the improvement of the photocatalytic performance of semiconductor photocatalysts. In current work, carbon vacancies are constructed successfully in graphitic carbon nitride (g-C 3 N 4) photocatalyst via magnesium vapor etching. Experimental results show that the formed carbon vacancies in g-C 3 N 4 photocatalyst can significantly improve the photocatalytic H 2 generation performance. XRD, FTIR, SEM/TEM, XPS and PL characterization data are employed to evidence the construction of carbon vacancies, which are revealed to be the reason for the enhancement of photocatalytic H 2 evolution. This work develops an alternative route to construct carbon vacancies in g-C 3 N 4 materials and gives an insight into the influence of vacancies on the photocatalytic performance of photocatalysts. • Carbon vacancies were constructed in g-C 3 N 4 via magnesium vapor etching. • The constructed carbon vacancies extend the light absorption to visible light. • The constructed carbon vacancies improve photogenerated charges separation efficiency. • Resultant enhancement of Photocatalytic H 2 generation activity was demonstrated. [ABSTRACT FROM AUTHOR]

In this work, a plasma treatment is employed to modify the surface properties of g-C 3 N 4 photocatalyst to enhance its photocatalytic performance. A suite of characterization methods are used to investigate the influence of plasma treatment on the surface properties, such as morphology, hydrophilicity and chemical bonding states. The comparative photocatalytic performance of pristine g-C 3 N 4 and the plasma-treated g-C 3 N 4 (PT-g-C 3 N 4 ) for the degradation of Rhodamine B (RhB) are demonstrated. The degradation efficiency under visible light irradiation for PT-g-C 3 N 4 is >2.0 times as high as that of pristine g-C 3 N 4 . The remarkably enhanced photocatalytic performance for pollution degradation results from the optimization of the surface properties induced by plasma treatment. These findings may provide a promising and facile approach to design high-performance photocatalysts. [ABSTRACT FROM AUTHOR]

Four types of g-C 3 N 4 materials were prepared with thiourea, urea, melamine and dicyandiamide as precursors. The differences of their piezocatalytic performance were studied in detail and the mechanism of piezocatalytic degradation of RhB was analyzed. [Display omitted] • g-C 3 N 4 with different piezocatalytic performance derived from variable precursors was studied. • N defects can destroy asymmetric structure of g-C 3 N 4 then reduce the piezocatalytic performance. • The sheet structure with low stacking degree is conducive to the occurrence of piezocatalytic effect. • •OH play a major role in the degradation of pollutants over g-C 3 N 4 piezocatalysis. In this paper, four types of graphitic carbon nitride (g-C 3 N 4) are prepared from different precursors by thermal polycondensation method and the piezocatalytic performance difference of the obtained g-C 3 N 4 materials are investigated in detail. g-C 3 N 4 derived from thiourea delivers best piezocatalytic performance basing on KMnO 4 reduction experiment and rhodamine B degradation experiment. According to the differences of piezocatalytic performance of these g-C 3 N 4 materials, effects of morphology, composition and defects on piezocatalytic performances are discussed. Reactive oxygen species (ROS) capture experiment showed that g-C 3 N 4 could produce ROS through piezoelectric effect and hydroxyl radical (•OH) played a major role in pollutant degradation. [ABSTRACT FROM AUTHOR]

• Presodiated B and N co-doped carbons was fabricated by a facial one-step synthetic process. • With the presence of NaBH 4 , g-C 3 N 4 transferred into presodiated B and N co-doped carbons. • as both presodiation agent a B and N led to promising Na+ storage capability as anode in SIBs. • Desirable ICE as high as 96.1% was recorded owing to the pre-incorporated Na+ ions. Heteroatoms doped carbon-based materials have attracted abundant attention as an anode material in high-energy density and low-cost sodium ions batteries (SIBs). However, the low initial Coulombic efficiency (ICE) resulted from the irreversible Na trapping and the formation of solid electrolyte interphase (SEI) is denounced in the practical application. In this work, presodiated B and N co-doped carbons are fabricated by a facial one-step synthetic process employing graphitic carbon nitride (g-C 3 N 4) as precursor and NaBH 4 as both presodiation agent and B sources. The high doping levels of B and N in the resultant carbon materials lead to a promising Na+ storage capability (308 mAh g−1 at 0.05 A g−1) when served as the anode in SIBs. More importantly, desirable ICE as high as 96.1% was recorded for the obtained presodiated B, N co-doped carbon material benefiting from the pre-incorporated sodium, which passivates the irreversible reactive sites. This work provides a novel route to realize simultaneous presodiation and B, N co-doping within carbon materials, enabling promising Na+ storage capability and enhanced ICE for application in SIBs. [ABSTRACT FROM AUTHOR]

In this work, veritable carbothermal synthesis of SrAlSi 4 N 7 :Eu2+ red-emitting phosphors using entire oxides raw materials and the elimination of residual carbon survived in materials via non-thermal plasma oxidation route are demonstrated. The crystal structure and photoluminescent properties of carbothermal-synthesized SrAlSi 4 N 7 :Eu2+ phosphors and the residual carbon elimination effect of non-thermal plasma oxidation are investigated in detail. Experiment results show that the residual carbon survived in carbothermal-synthesized SrAlSi 4 N 7 :Eu2+ phosphors could be eliminated effectively by non-thermal plasma oxidation, leading to the significant enhancement of luminescent properties. The presented work affords an economic carbothermal reduction method to synthesize nitride phosphors using low cost entire oxides raw materials and recommends a promising approach to eliminate the residual carbon in carbothermal-synthesized materials. • SrAlSi 4 N 7 :Eu2+ phosphor was synthesized by carbothermal method using entire oxides raw materials. • Elimination of residual carbon was demonstrated by non-thermal plasma oxidation technology. • Luminescent property was enhanced owing to the removal of residual carbon after plasma treatment. • The elimination of residual carbon by oxygen-plasma was higher than that by air-plasma. [ABSTRACT FROM AUTHOR]