CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Yanli Chen,Fengyun Su,Haiquan Xie,Ruiping Wang,Chenghua Ding,Jindi Huang,Yixue Xu,Liqun Ye
Step-scheme (S-scheme) heterojunctions of S-doped g-C 3 N 4 (SCN) and N-doped MoS 2 (NMS) were constructed by a one-step thermal polycondensation method in Ar atmosphere using thiourea and ammonium tetrathiomolybdate as starting materials. X-ray photoelectron spectra revealed the formation of new N-Mo and C-S-Mo bonds between SCN and NMS and enhanced NMS purity. The as-prepared NMS/SCN with an NMS ratio of 19.3 wt% showed the highest photocatalytic activity. Within 4 h of illumination, its H 2 generation rate reached 658.5 μmol/g/h, which was about 23 and 38 times higher than that of pure SCN (28.8 μmol/g/h) and NMS (17.4 μmol/g/h), respectively. UV–vis diffuse reflectance spectra (DRS), surface photovoltage spectrum (SPV), photoluminescence (PL) spectra and electrochemical tests revealed the extended visible light absorption and enhanced photo-generated carrier separation of the formed S-scheme heterojunction. The mechanism and driving force of charge transfer and separation in S-scheme heterojunction photocatalysts are investigated and discussed.
研究领域:
材料科学
·
光催化
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2021
·
IF 7.312
Li Kang,Zhongkang Han,Haibo Yu,Qiangshun Wu,Hanpei Yang
In this study, novel titanate nanosheets/g-C 3 N 4 (TNS/CN) and titanate nanosheets/sulfur-doped g-C 3 N 4 (TNS/SCN) heterojunctions were successfully fabricated by the in-situ assembly for the efficient removal of tetracycline hydrochloride (TC-HCl). TNS/SCN achieved 1.87, 7.89 and 3.27 times increases in photodegradation performance compared to TNS/CN, TNS and SCN, respectively, due to the collaboration of the unique 2D/2D hetero-architecture, synergistic effects of different roles of sulfur doping in SCN and TNS/SCN, and step-scheme interfacial charge transport. The unique 2D/2D hetero-architecture provided numerous convenient nanochannels for charge transport, while sulfur doping introduced the impurity states and defects in SCN, which contributed to the enhanced visible-light absorption and efficient separation of photo-generated carriers. Besides, sulfur doping induced the distinct difference in Fermi levels and enhanced electronic coupling between TNS and SCN as evidenced by density functional theory calculations and X-ray photoelectron spectra, which facilitated the interfacial charge transport in heterojunction. The accelerated interfacial charge transport in TNS/SCN driven by the enhanced internal electric field promoted the efficient separation of photogenerated carriers. TNS/SCN can achieve excellent stability and reusability after four consecutive cycles, over a wide pH range or under coexisting anion conditions. Mechanisms toward the TC-HCl degradation and step-scheme interfacial charge transport were also proposed. This work provides a new strategy to enhance the catalytic performance of step-scheme heterojunction.
研究领域:
材料科学
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环境科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Functional Materials Letters
·
2021
·
IF 2.17
Dan Yang,Lei Zhao,Xueting Feng,Lili Ma,Hanming Ding
As a potential nonmetal activator of peroxymonosulfate (PMS), g -C 3 N 4 becomes a hot material owing to its superior chemical and physical properties. Nevertheless, pristine g -C 3 N 4 is unsatisfactory for PMS activation because of its limited photo-generated charge separation and low specific surface area. Herein, a porous sulfur-doped g -C 3 N 4 (S-doped g -C 3 N 4 ) has been prepared through a one-step calcination route without a template. The in - situ doping of sulfur element and the formation of porous morphology have been confirmed via various characterization methods. The catalytic activity of porous S-doped g -C 3 N 4 is approximately 6.2-fold higher than that of the pristine g -C 3 N 4 on rhodamine B (RhB) decomposition in aid of the photo-assisted PMS activation. The superior catalytic activity and high stability of the porous S-doped g -C 3 N 4 catalyst in a wide pH range are attributed to its higher specific surface area, enriched active sites, efficient photo-induced charge separation, and increased visible-light utilization. Meantime, a synergistic effect between the PMS activation process and the photocatalytic process is conducive to produce abundant radicals for the RhB degradation. This study offers new insight into further developing highly efficient nonmetal heterogeneous catalysts for wastewater treatment.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Yicheng Dou,Tingting Yan,Zhipeng Zhang,Qiya Sun,Lin Wang,Yongmei Li
In this study, peroxydisulfate (PDS) was activated by synthesized sulfur-doped g-C 3 N 4 (SCN) under visible-light irradiation and was adopted to enhance the removal of spiramycin, which is an important precursor of N-nitrosodimethylamine (NDMA). Specifically, 95.4% of spiramycin (≤10 mg/L) was removed in 60 min under the conditions of an initial value of pH of 7.0, an SCN dose of 1.0 g/L, and a PDS dose of 200 mg/L, and its degradation fitted well with the pseudo first-order kinetics. Electron paramagnetic resonance analysis and trapping experiments confirmed that ·O 2 − and h + were the main oxidizers for the degradation of spiramycin, and ·SO 4 − and ·OH also participated in the removal of spiramycin. The removal of spiramycin in the PDS/SCN visible-light catalytic system occurred through three different pathways: aldehyde oxidation , cleavage of C-O bond and demethylation. Notably, 61.4% of NDMA formation potential (FP) was reduced after the reaction. The SCN catalyst was stable and its catalytic performance was excellent in the PDS/SCN system, as the spiramycin removal efficiency decreased only slightly from 95.4% to 87.3% after being reused three times. Therefore, our study not only provides an alternative method for removing spiramycin but can also can significantly reduce NDMA FP.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
·
2019
·Vol. 19
·期 9
·5736-5742
·
IF 1.093
Bai Jirong,Lv Wenhua,Xu Haiyang,Chen Gang,Ni Zhijiang,Wang Zhilei,Qin Hengfei,Zheng Zheng,Li Xi
Ag3PO4/sulfur-doped g-C3N4 heterojunctions were fabricated by the means of a facile calcination and co-precipitation method. Structural characterization suggested that Ag3PO4 was successfully loaded onto sulfur-doped
g-C3N4. The absorption band edges of sulfur-doped g-C3N4 were shifted to the longer wavelength in comparison with bulk g-C3N4. The Ag3PO4/sulfur-doped g-C3N4 heterojunctions manifested
substantially higher visible-light photocatalytic performance as compared with Ag3PO4/bulk g-C3N4. Photoluminescence spectra suggested that the stable Ag3PO4/SGCN heterojunctions could effectively address the electron—hole
recombination rate, together with remarkably enhancing the photocatalytic activity. The enhancement of light absorption and better dispersion in Ag3PO4/sulfur-doped g-C3N4 provide more migration channels, together with posing crucial responsibility
for the enhanced photocatalytic performance.
研究领域:
材料科学
·
化学
·
环境科学
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2021
·
IF 10.588
Lin Wang,Qiya Sun,Yicheng Dou,Zhipeng Zhang,Tingting Yan,Yongmei Li
A novel ternary recyclable Fe 3 O 4 /graphene/sulfur-doped g-C 3 N 4 (Fe 3 O 4 /GE/SCN) composite catalyst was synthesized and adopted in a visible-light driven catalytic system for the degradation of ranitidine, which is an important precursor of the emerging disinfection by-product of N-nitrosodimethylamine (NDMA). The addition of GE and Fe 3 O 4 significantly improved the interface charge transfer of SCN, increased the light collection efficiency and decreased the photogenerated charge recombination efficiency. Considering both the ranitidine removal efficiency and catalyst recovery, the Fe 3 O 4 mass fraction of 20% (20%-Fe 3 O 4 /GE/SCN) was recommended. Ranitidine (≤ 2 mg/L) was completely removed in 60 min under the conditions of an initial pH of 7.0 and a 20%-Fe 3 O 4 /GE/SCN dose of 1.0 g/L, and its degradation fitted well with the pseudo first-order kinetics model. Electron paramagnetic resonance analysis and trapping experiments confirmed that ·O 2 − , ·OH and h + participated in the degradation of ranitidine. Ranitidine was removed through the pathways of demethylation and hydroxylation based on the analysis of the detected degradation intermediates, and 57.3% of the NDMA formation potential (FP) was reduced after the reaction. The visible-light driven 20%-Fe 3 O 4 /GE/SCN catalytic technology is a promising method not only for the control of NDMA FP but also the catalyst could be recovered and reused.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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