Journal of Materials Research and Technology-JMR&T
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2021
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IF 5.039
Yushuai Chen,Bo Yang,Wenyu Xie,Xueying Zhao,Zhuan Wang,Xintai Su,Chao Yang
Insufficient active sites and fast charge carrier recombination are detrimental to photocatalytic activity of graphitic carbon nitride (g-C 3 N 4 ). In this work, a combination of pore creating with thermal exfoliation was employed to prepare porous g-C 3 N 4 nanosheets for photocatalytic water splitting into hydrogen. Hexadecyl trimethyl ammonium chloride (CTAC) as the soft template promoted the formation of porous g-C 3 N 4 during the thermal condensation of melamine. On further post-synthesis calcination, the porous g-C 3 N 4 aggregates were exfoliated into discrete nanosheets, accompanied by an increase in specific surface area and defects. Optimal porous g-C 3 N 4 nanosheets achieved 3.6 times the photocatalytic hydrogen evolution rate for bulk counterpart. The enhanced photocatalytic activity may be ascribed to TCN-1%CTAC has larger specific surface area, stronger optical absorption intensity and higher photogenerated electron–hole separation efficiency. The external quantum efficiency of TCN-1%CTAC was measured to be 3.4% at 420 nm. This work provides a simple combinatorial strategy for the preparation of porous g-C 3 N 4 nanosheets with low cost, environmental friendliness and enhanced photocatalytic activity.
研究领域:
材料科学
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环境科学
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
DIAMOND AND RELATED MATERIALS
·
2024
·
IF 4.3
Xiaoyu Jiang,Xiang Li,Yumin Liu,Haifa Zhai,Gongke Wang
The preparation of ultrathin nanosheets is conducive to increasing the material's specific surface area and introducing suitable defect sites. This facilitates the enhancement of the separation efficiency of photogenerated charge carriers and improves the adsorption and degradation efficiency toward pollutants. Various nitrogen-rich precursors were employed for the synthesis of bulk g-C 3 N 4 (BCN) and its ultrathin nanosheets, with a focus on investigating their photocatalytic performance. The degree of polymerization of g-C 3 N 4 influenced its hydrogen bonding and C/N ratio, affecting the ultrathin nanosheet microstructure. Oxidation disrupted the tri- s -triazine rings in the ultrathin nanosheets of g-C 3 N 4 prepared via dicyandiamide. However, g-C 3 N 4 prepared from urea and melamine as precursors retained its primary characteristics after thermal oxidative exfoliation, attributed to interlayer hydrogen bonds, small lateral size at low polymerization degrees, and increased vacancy defects. In the photocatalytic degradation system, two-dimensional nanosheets of g-C 3 N 4 synthesized from urea exhibited the highest catalytic efficiency.
研究领域:
材料科学
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环境科学
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化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
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2019
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IF 4.309
Shengkai Yang,Kelei Zhuo,Zezhong Zhang,Jianming Liu,Guangyue Bai,Jianji Wang
The low yield of graphene in the sonication-assisted aqueous-phase exfoliation is one of the challenges to its large-scale production in industry. Here, we report that hydrothermal exfoliation of graphite into graphene in NaF and polyether F127 (F127) solution can achieve a high concentration (0.55 mg mL–1) or yield (8.2%) of graphene in a low-cost, environmentally friendly manner. The defect of as-exfoliated graphene is comparable to that produced by the sonication-assisted exfoliation. In the exfoliation process, NaF and F127 are regarded as the intercalator and stabilizer. The thermal motion of H2O and F–/Na+ ion pairs, Brownian motion of graphite particles, and thermally agitation of graphite interlayers are the main driving force for exfoliating graphite. In addition, as filler of epoxy resin (EP), the graphene can enhance considerably the anticorrosion performance of EP coating. The hydrothermal exfoliation in NaF and F127 solution provides a new choice for the large-scale production of graphene.
研究领域:
材料科学
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化学工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
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2016
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IF 2.758
Yanan Li,Min-Qiang Wang,Shu-Juan Bao,Shiyu Lu,Maowen Xu,Dingbiao Long,Shihua Pu
In this work, ultrathin graphene-like carbon nitride nanosheets with rich nanoporous and excellent hydrophilic characteristics were synthesized by a simple and effective thermal exfoliation of bulk g-C 3 N 4 . In order to fully understand the effect of thermal exfoliation conditions on the texture, surface state, and photocatalytic activity of the resulting g-C 3 N 4 , a series of exfoliated g-C 3 N 4 were prepared by adjusting the thermal exfoliation temperature and time. The detailed characterization and analysis distinctly suggested that increasing exfoliation temperature led to a large number of nitrogen vacancies and increased specific surface area, further prolonging exfoliation time, the thermal exfoliation degree was enhanced, more carbon vacancies and enlarged pore volume formed in the resulting products. Further, the exfoliation degree and photocatalytic ability of the resultant products were enhanced by increasing thermal exfoliation temperature and time. The optimized ultrathin graphene-like carbon nitride nanosheets exhibited a 89.6% degradation efficiency for Rh6G only in 10 min, which was much faster than other such nanosheets reported in previous literature.
研究领域:
材料科学
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环境科学
✓ 已验证
DOI
高影响因子
ACS Applied Materials & Interfaces
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2017
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IF 7.504
Yasin Orooji,Feng Liang,Amir Razmjou,Sha Li,Mohammad Reza Mofid,Quan Liu,Kecheng Guan,Zhengkun Liu,Wanqin Jin
Flux and antifouling properties of mixed matrix membranes (MMMs) are yet to attain satisfactory status. The objective of this study is to find a method for mitigating the biofouling of poly(ether sulfone) (PES) ultrafiltration membranes via blending of thermoexfoliated vermiculite (VMT). Flow cytometry analysis shows that the behaviors of Bacillus subtilis 168 as a Gram-positive bacterium and Escherichia coli DH5 alpha as a Gram-negative bacterium were different. Hence, cell property is a suspected contributory factor in biofilm formation. Accordingly, considering the local predominant bacterial strains, a regionally customized membrane could scientifically be an expert solution for biofouling mitigation. Fabricated composite membranes have shown a higher flux compared to control PES membrane. Among all composite membranes, the PES-VMT0.10 had the highest flux of 476.4 L/(m2 h) (LMH) before fouling, and the highest flux of 210.7 LMH after three cycles of usage. In addition, the rejection rate of the PES-VMT0.15 The bovine serum albumin (BSA) sample was >77%, while that of the PES-VMT0.10 was >84%. The results of the static BSA adsorption test and the bacterial attachment test indicated that the membranes with macro-roughness on their surface showed better antibiofouling resistance. The antifouling properties of the modified membranes were also improved, because of their optimal wettability. On one hand, the hydrophilicity of membranes caused damaging both Gram-positive and Gram-negative bacteria and bacteriocidal effect. On the other hand, BSA adsorption and bacterial attachment on the membrane surface were affected by pore diameter.
研究领域:
材料科学
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环境工程
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微生物学
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产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
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2016
·Vol. 4
·期 28
·6720-6726
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IF 5.066
Xiaolong Lu,Rongguo Wang,Fan Yang,Weicheng Jiao,Wenbo Liu,Lifeng Hao,Xiaodong He
Lots of top-down approaches by weakening the van der Waals interaction between adjacent layers and breaking up the covalent chemical bonds in each layer have been reported to prepare QDs of layered materials due to the stacked structures. However, much attention has been focused on graphene and layered transition-metal dichalcogenides (TMDs), seldomly on layered transition-metal oxides (TMOs). Herein, a modified top-down method combining intercalation and thermal exfoliation is reported to prepare high-yield QDs of layered MoO3. Alkylamine was first intercalated into MoO3 layers to weaken the van der Waals forces. Then, the covalent bonds in each MoO3 layer were broken down under a sudden increase in gas pressure generated by the decomposition of alkylamines after rapid heating. These fractured particles were further incised to QDs by sonication. The as-prepared MoO3 QD dispersion showed a plasmon resonance after simulated solar light illumination. Surprisingly, their plasmon peak red shifted with an extended illumination time, which was different from the reported MoO3 nanosheets. This reported method is expected to extend to other QDs of layered materials providing that their bulk materials can also be intercalated.
研究领域:
材料科学
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纳米技术
✓ 已验证
DOI
高影响因子
Journal of Nanomaterials
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2019
·Vol. 2019
·期 1
·5290496
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IF 2.233
Zhenzhu Yu,Fei Nan,Lu Su,Shaofei Zhang,Yan He
Intercalation and exfoliation are key steps in the preparation of graphene by thermal exfoliation, and they determine the quality of the final product. Therefore, it is important to explore the influence of intercalation agents on the intercalation and exfoliation of graphite. In this article, ammonium bicarbonate is intercalated into graphite with different degrees of oxidation to form a graphite intercalation compound (GIC) by means of ultrasound and stirring. Then, they are exfoliated by being heated at high temperatures. After ammonium bicarbonate intercalation and heating treatment, XRD, TG, and BET show that the intercalation and exfoliation effect of graphite oxide (GO) is better than that of graphite (G) and expanded graphite (EG). The intercalation mechanism is that the ammonia molecule in ammonium bicarbonate solution contains a wedge-shaped structure and active point, which provides empty orbits for graphite electrons and forms edge intercalation through physical interaction at the same time.
研究领域:
材料科学
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纳米材料
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物理化学
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碳材料
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功能材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）