CHEMOSPHERE
·
2022
·
IF 8.943
Cheng Cheng,Dongyun Chen,Najun Li,Hua Li,Qingfeng Xu,Jinhui He,Jianmei Lu
This paper reports the application of NH 2 -MIL-125(Ti) modified carbon nitride C v -C 3 N 4 with carbon vacancies in the removal of NO. We performed a series of characterizations of the complex and compared various ratios with the individual components. The results of UV spectrum analysis show that the composite's range of light absorption expanded due to the modification of Ti metal–organic framework. Furthermore, the results of photocurrent and electrical impedance indicate the compound has a better ability to generate and transfer electrons . The increase in the compound's NO removal efficiency (up to 63%) indicates that MOF has a positive effect on C v -C 3 N 4 modification—a good method for photocatalysis . Moreover, the compound can promote photocatalysis in a favorable direction.
研究领域:
材料科学
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环境科学
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DOI
高影响因子
Cell Reports Physical Science
·
2022
·
IF 7.832
Yang Ding,Soumyajit Maitra,Daniel Arenas Esteban,Sara Bals,Henk Vrielinck,Tarek Barakat,Subhasis Roy,Gustaaf Van Tendeloo,Jing Liu,Yu Li,Alexandru Vlad,Bao-Lian Su
Artificial photosynthesis of H 2 O 2 , an environmentally friendly oxidant and a clean fuel, holds great promise. However, improving its efficiency and stability for industrial implementation remains highly challenging. Here, we report the visible-light H 2 O 2 artificial photosynthesis by digging pro-superoxide radical carbon vacancies in three-dimensional hierarchical porous g-C 3 N 4 through a simple hydrolysis-freeze-drying-thermal treatment. A significant electronic structure change is revealed upon the implantation of carbon vacancies, broadening visible-light absorption and facilitating the photogenerated charge separation. The strong electron affinity of the carbon vacancies promotes superoxide radical ( ⋅ O 2 − ) formation, significantly boosting the H 2 O 2 photocatalytic production. The developed photocatalyst shows an H 2 O 2 evolution rate of 6287.5 μM g −1 h −1 under visible-light irradiation with a long cycling stability being the best-performing photocatalyst among all reported g-C 3 N 4 -based systems. Our work provides fundamental insight into highly active and stable photocatalysts with great potential for safe industrial H 2 O 2 production.
研究领域:
材料科学
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环境科学
·
化学
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DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2022
·Vol. 10
·期 32
·16873-16882
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IF 14.511
Jianghong Zhao,Rihui Mu,Ya Zhang,Zhidong Yang,Hongxia Zhang,Hu Shi,Min Zhang,Zhanfeng Zheng,Pengju Yang
Polymeric carbon nitride (PCN) semiconductors are appealing light-transducers for photocatalytic redox reactions owing to their unique band gap and stability. However, pristine PCN exhibits moderate efficiency due to the low surface area and serious charge recombination. The delamination of PCN into few-layered nanosheets is an effective strategy to improve the reaction efficiency, but remains a huge challenge. Herein, we report a general approach to prepare few-layered PCN nanosheets by an acetic acid vapor etching strategy. The bulk PCNs obtained from typical precursors including melamine, dicyandiamide, and trithiocyanuric acid can be exfoliated into few-layered nanosheets, while their surfaces can be engineered to present carbon vacancies (CVs). Results confirm that the few-layered nanosheets endow PCN with abundant reactive sites, effective charge separation, and prolonged charge lifetime. Furthermore, experimental and theoretical calculation results verify that the CVs within PCN nanosheets can facilitate electron transfer from the PCN nanosheets to the Pt cocatalyst, significantly lowering the reaction barrier for the formation of H* species. As a result, the PCN nanosheets (with Pt as a cocatalyst) exhibit excellent photocatalytic activity for hydrogen production with visible light. The apparent quantum yield (AQY) for hydrogen production at 400 nm reaches as high as 16.22%, exceeding most of the reported AQY values of PCN-based photocatalysts for hydrogen production. Moreover, it was found that the CVs within PCN nanosheets are favorable for the adsorption and activation of O2 molecules owing to the delocalization of the non-bonding electrons around defects to the absorbed O2, considerably expediting the reaction kinetics of phenol degradation under visible light. This work not only provides a general methodology for the synthesis of few-layered PCN nanosheets but also establishes the connection between the catalyst structure and performance.
研究领域:
材料科学
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催化化学
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DOI
高影响因子
Catalysis Science & Technology
·
2021
·Vol. 11
·期 9
·3270-3278
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IF 6.119
Huihui Li,Fuchun Ning,Xiaofei Chen,Anye Shi
Porous carbon nitride nanosheets with carbon and nitrogen double vacancies have been synthesized by a soft template-supported one-pot method. Besides their highly defined and unambiguous structure, they also show minimal thickness and high crystallinity. This porous carbon nitride exhibits great enhancement in photocatalytic hydrogen evolution activity (297.6 μmol h−1), which is 9.6 times higher than 31.2 μmol h−1 of the pristine one. An apparent quantum yield of 12.7% at 420 nm for hydrogen production can be achieved over these porous nanosheets. The detailed investigation suggests that there are carbon vacancies along with nitrogen vacancies. Besides nitrogen vacancies, carbon vacancies also play a positive role in the improvement of hydrogen evolution. In addition, the photocatalytic performance especially hydrogen evolution increases with the increase of the C/N ratio.
研究领域:
材料科学
·
能源科学
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Huimin Yan,Qing Xi,Fangxia Xie,Jilong Qin,Xiao Zhang,Houfen Li,Yawen Wang,Xiaoming Gao,Caimei Fan,Jianxin Liu,Zhuobin Yu,Rui Li
Accelerating the separation and transfer of photogenerated electron to the active site is an effective strategy for enhancing the photocatalytic hydrogen evolution . However, it is generally limited by the scarcity of active sites, as well as the sluggish photogenerated electron transfer kinetics. Herein, a g-C 3 N 4 catalyst with controllable carbon vacancy and hydrogen bond was prepared using a hot–cold cycles heat treatment. It is demonstrated that after hot–cold cycles, abundant carbon vacancies were introduced into the catalyst and hydrogen bonds were broken. The abundant carbon vacancies not only provide additional electron-active sites, affords more opportunities for photogenerated electron to transfer to the active site, but also optimize the reaction environment for photogenerated electrons by regulating the hydrogen adsorption kinetics of the photocatalyst. Additionally, the broken hydrogen bonds promotes electron transfer to the active site. The combined action of the two effectively enhances the separation and transfer of photogenerated electron to the optimal active site, ultimately leading to a significant increase in photocatalytic hydrogen evolution. Consequently, the g-C 3 N 4 resulting from the fourth cycles (CN-4) demonstrates a substantial improvement in the performance of photocatalytic hydrogen evolution under visible light irradiation (1.69 mmol·g −1 ·h −1 ), which is 4.05 times higher than initial g-C 3 N 4 . This work may provide new insights into the defect and hydrogen bond regulation design of g-C 3 N 4 .
研究领域:
材料科学
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能源化学
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产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 106
·期 7
·4382-4389
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IF 3.9
Yongqiang Tan,Wei Liao,Zhen Teng,Haibin Zhang
Two high-entropy carbides, including stoichiometric (Zr,Ti,Nb,Ta,Hf)C and nonstoichiometric (Zr,Ti,Nb,Ta,Hf)C 0.8 , were prepared from monocarbides and ZrH 2 . Their sinterability, microstructures, mechanical properties, thermophysical properties, and oxidation behaviors were systematically compared. With the introduction of carbon vacancy, the sintering temperature was lowered up to 300°C, Vickers hardness was almost unaffected, whereas the strength decreased significantly generally due to the decrease of covalent bonds. The thermal conductivity shows a 50% decrease for nonstoichiometry high-entropy carbide, which is a major consequence of the lower electrical conductivity. The oxidation resistance in high temperature water vapor was not sensitive to carbon stoichiometry.
研究领域:
材料科学
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机械工程
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Jicheng Li,Hengzhong Fan,Qiangqiang Zhang,Hongxiang Chen,Yunfeng Su,Junjie Song,Litian Hu,Yongsheng Zhang
High-entropy carbides have attracted considerable attention owing to their high melting point and excellent mechanical properties at high temperatures. However, exposures to high temperature environments are often accompanied by oxidation problems. Previous studies generally focused on improving oxidation properties by adding antioxidant elements. However, improving the oxidation properties intrinsically by modifying the crystal structure is still lacking. In this work, we innovative introduced tunable carbon vacancies into high-entropy carbides successfully.Consequently, the oxidation property of high-entropy carbides was improved, with the effect of carbon vacancies on the oxidation property was systematically investigated in this study. The (Ti 0.2 V 0.2 Nb 0.2 Mo 0.2 W 0.2 )C x exhibits the best oxidation resistance property when x = 0.7, with the highest initial oxidation temperature and peak weight gain temperature (950.2 °C) and the lowest mass gain rate (25.2 %). This is mainly attributed to the formation of a higher number of carbonaceous oxides, which hinder the internal oxidation process.
研究领域:
材料科学
·
高温材料
·
表面工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Cleaner Production
·
2024
·
IF 9.7
Min Wang,Guanghua Lu,Runren Jiang,Tianjian Dang,Yufang Chen,Jianchao Liu,Zhenhua Yan,Jun Hou
The widespread use of bisphenol F (BPF) as the commonly used alternative to bisphenol A (BPA) in the industry and its hazardous effects on ecological system and human health have attracted widespread attention. In this study, V C -FCN 0.3 hollow nanotube structure with confinement space effects and combined carbon vacancies was constructed by the spatial self-corrosion strategy, which effectively addressed the inherent limitations of conventional carbon nitride and achieved 100% removal rate of BPF within 2 h under visible light. Carbon vacancies not only accelerated the transfer of photogenerated carriers, but also enhanced the adsorption and activation of oxygen that accelerating the production of ·O 2 − , the main active species in this system. In addition, the special spatial structure shortened the mass transfer distance between the target pollutants and the active species. What's more, V C -FCN 0.3 showed excellent, stable, and eco-friendly photocatalytic degradation of bisphenol F over a wide pH range and in five water matrices, contributing effectively to the solution of purification of wastewater containing bisphenol analogues.
研究领域:
环境科学
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材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Materials Chemistry Frontiers
·
2022
·Vol. 6
·期 14
·1964-1972
·
IF 8.683
Mingrui Guo,Meng Chen,Jixiang Xu,Jing Wang,Lei Wang
The intramolecular doping of donor units or acceptor units in carbon nitride (g-C3N4, CN) is regarded as an effective method for regulating electron structure and enhancing the catalytic activity of CN. Herein, benzene rings and eosin Y (EY) co-grafted CN with carbon vacancies (EY-PhCN) was prepared by calcining a supermolecular precursor consisting of melamine, cyanuric acid, and benzonquanmine followed by covalently hooking the EY. Theoretical and experimental results demonstrated the directional electron transfer, spatially isolated electron–hole pairs and increased light response in the resulting ultrathin holey EY-PhCN. An optimal H2 production rate of 4.44 mmol g−1 h−1 was obtained over the 1%Pt-loaded EY-PhCN catalyst. The corresponding apparent quantum yield was 27.38% at 420 nm. Moreover, the EY-PhCN exhibited high CO2 reduction rate with H2O. The yields of CO and CH4 were 61.91 and 13.75 μmol g−1, respectively within 5 h light irradiation, higher than that of CN (CO: 24.60 μmol g−1, CH4: 8.51 μmol g−1). The work may give new insight into associating carbon vacancies and edge decoration on CN to achieve remarkably enhanced photocatalytic activity.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2021
·Vol. 28
·期 3
·825-834
·
IF 2.496
Zhang Long,Ge Jianhua,Liu Yujie,Zheng Xuyang,Du Pingwu
Solar-driven reduction of dinitrogen to ammonia remains greatly challenging due to the stable triple bond between N atoms. In this study, g-C 3 N 4 photocatalysts were synthesized via ozone etching method. Due to the O 3 treatment, the resulting photocatalysts were rich in carbon vacancies. Etching g-C 3 N 4 with ozone for two hours (O 3 GCN-2), resulted in the decrease of size, and the structure becoming less compact. The specific surface area of O 3 GCN-2 increased up to ~ 12.751 m 2 ·g −1 , in comparison with that of the bulk g-C 3 N 4 (BGCN) that was only ~ 5.652 m 2 ·g −1 . The nitrogen fixation efficiency of O 3 GCN-2 was 2.72 times higher than that of BGCN under visible light irradiation. UV–vis, electrochemical impedance spectroscopy, and photocurrent measurements showed that O 3 GCN-2 had enhanced visible light absorption properties and enhanced electron–hole separation efficiency. The possible mechanism of the photocatalytic nitrogen fixation was also investigated. This study may provide a novel idea and insight for the design of efficient photocatalysts for nitrogen fixation.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Jin Gao,Junxia Shao,Hua Li,Najun Li,Dongyun Chen,Qingfeng Xu,Jianmei Lu
The sluggish charge transfer and fast recombination of charge carriers is a determining factor limiting photocatalytic efficiency of carbon nitride. Herein, carbon vacancies and Rh 2 O 3 nanoparticles were sequentially introduced into CN to accelerate photo-generated electron and hole transfer simultaneously, thereby improving the photocatalytic performance of CN to achieve the complete removal of Bisphenol A (BPA) in 15 min. Mechanism analyses reveal that the modification of the carbon vacancies regulates the active charge carriers, excitons and trap states, thus enhances the carrier separation capabilities and light absorption. Meanwhile, the in situ photodeposited Rh 2 O 3 nanoparticles, as a hole-transfer mediator, maximally suppress recombination of photogenerated charges. These synergistic effects result in promoting the separation and transfer of charge carriers and thus improving photocatalytic performances. This strategy can serve as guideline for the reasonable design of efficient photocatalysts for phenolic wastewater remediation.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Jianhui Shi,Hui Wang,Jianhui Nie,Tiantian Yang,Chenke Ju,Kaikai Pu,Jiating Shi,Ting Zhao,Houfen Li,Jinbo Xue
Exfoliating bulk graphite phase carbon nitride (g-C 3 N 4 ) into 2D nanosheets is considered to be an effective method to enhance its photocatalytic activity . However, optical absorption capacity of the exfoliated g-C 3 N 4 nanosheets are lower than that of the original bulk g-C 3 N 4 due to the quantum size effect . Here, the ultrathin graphite phase carbon nitride nanosheets containing both carbon vacancy and cyano group (UCNS 580 ) were prepared by two-step calcination in air with the assistance of KOH. The formation and position of carbon vacancy and cyano group were first investigated and determined. The simultaneous introduction of carbon vacancy and cyano group not only improved light absorption range and intensity of g-C 3 N 4 nanosheets, but also more importantly constructed a fast transfer channel for photogenerated electrons, further enhancing the separation efficiency and migration ability of photogenerated carriers. The cyano group as the accumulation center of photogenerated electrons and the oxygen adsorption center increased the proportion of one-step two-electrons reaction path to efficiently generate H 2 O 2 . As a result, UCNS 580 exhibited highly boosted H 2 O 2 generation activity, its H 2 O 2 production yield for 6 h reached 939 µmol/L and the formation rate was up to 4167 µM h −1 g −1 , which was in priority in the reported literature under the same conditions.
研究领域:
材料科学
·
光催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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