Radiation Effects and Defects in Solids
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2023
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IF 1
Jahfer M. Smail,Habeeb Hanna Mansour,Saddon T. Ahmad
In this study, the activity concentrations of natural and artificial radionuclides in 18 sediment samples were investigated from Iraq’s Upper and Lower Dukan Dam using the high-purity germanium (HPGe) detector as a gamma-ray spectrometry technique. The results revealed that the values of the activity concentration of 226Ra, 232Th, 40K, and 137Cs sediment ranged from (2.85–24.60 Bq kg−1), (1.27–7.56 Bq kg−1), (42.14–346.60 Bq kg−1), and (0.14–3.62 Bq kg−1), respectively. The radiological risk parameters such as radium equivalent activity, absorbed dose rate, annual effective dose equivalent, and external hazard index were determined and found to be 30.98 Bq kg−1, 14.97 nGy h−1, 29.62 nGy h−1, 0.019 mSv y−1, 0.153 mSv y−1, 0.08, and 0.11, respectively. The observed mean values were comparable to internationally recommended values. The field dose rates were measured using the RIIDEye Handheld Radiation Isotope Identifier, and the range was 23.5 nsv h−1–80.6 nsv h−1. The data obtained in this study can be used as a baseline for future investigations of radioactivity background in the investigated area.
研究领域:
环境放射性
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放射性评价
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环境监测
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核地球物理学
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健康物理
✓ 已验证
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2024
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IF 9.4
Mengxia Shen,Qingqing Liu,Jiaojiao Sun,Chanjuan Liang,Chuanyin Xiong,Chen Hou,Jianfeng Huang,Liyun Cao,Yongqiang Feng,Zhen Shang
Single-atom catalysts (SACs), with precisely controlled metal atom distribution and adjustable coordination architecture, have gained intensive concerns as efficient oxygen reduction reaction (ORR) electrocatalysts in Zn-air batteries (ZAB). The attainment of a monodispersed state for metallic atoms anchored on the carbonaceous substrate remains the foremost research priority; however, the persistent challenges lie in the relatively weak metal-support interactions and the instability of captured single atom active sites. Furthermore, in order to achieve rapid transport of O 2 and other reactive substances within the carbon matrix, manufacturing SACs based on multi-stage porous carbon substrates is highly anticipated. Here, we propose a methodology for the fabrication of carbon aerogels (CA)-supported SACs utilizing papermaking nanofibers , which incorporates advanced strategies for N -atom self-doping, defect/vacancy introduction, and single-atom interface engineering. Specifically, taking advantages of using green and energy-efficient feedstocks, combining with a direct pore-forming template volatilization and chemical vapor deposition approach, we successfully developed N -doped carbon aerogels immobilized with separated iron sites (Fe-SAC@N/CA-Cd). The obtained Fe-SAC@N/CA-Cd exhibited substantially large specific surface area (S BET = 1173 m 2 /g) and a multi-level pore structure, which can effectively mitigate the random aggregation of Fe atoms during pyrolysis. As a result, it demonstrated appreciable activity and stability in catalyzing the ORR progress (E 1/2 = 0.88 V, E onset = 0.96 V). Furthermore, the assembled liquid electrolyte-state Zn-air batteries (LES-ZAB) and all-solid-state Zn-air battery (ASS-ZAB) also provides encouraging performance, with a peak power density of 169 mW cm −2 for LES-ZAB and a maximum power density of 124 mW cm −2 for ASS-ZAB.
研究领域:
材料科学
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电化学
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能源存储
✓ 已验证
产品关联
DOI
PubMed
高影响因子
FUEL
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2024
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IF 6.7
Xiaoting Zhao,Xieraili Maimaitiyiming,Mamutjan Tursun,He Lin
To enhance the large-scale manufacture of zinc-air batteries (ZAB) and direct methanol fuel cells (DMFC), high-performance oxygen reduction reaction (ORR) catalysts must be developed. In this study, corn stalk binder (CS binder) was added to corn stalk (CS), the ratio between the two was adjusted, and the structure and morphology of the carbon material was altered to create a biocarbon substrate material (15 wt% N/C (CS)) with ORR catalytic activity. It had a half-wave potential (E 1/2 ) that was 29 mV greater than the pure carbon substance from CS (0 wt% N/C(CS)). Using Fe and N coordination-Hemin, an iron single-atom catalyst (15 wt% Fe N/C (CS)) was created based on this. Commercial Pt/C catalysts are anticipated to be replaced by the 15 wt% Fe N/C (CS), which demonstrated exceptional peak power density in both DMFC and ZAB cell tests. The catalytic mechanism of 15 wt% Fe N/C (CS) is explained by density functional theory (DFT), whereby the 15 wt% N/C (CS) carbon substrate rich in faulty structures creates space for the effective use of the iron single-atom reactive sites. Furthermore, the Fe N sites reduced the overpotential of ORR, which promoted the adsorption and reduction of oxygen molecules at the active sites.
研究领域:
材料科学
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能源化学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2021
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IF 19.503
Wanqing Li,Lei Wu,Xiaochao Wu,Chuan Shi,Yongliang Li,Lei Zhang,Hongwei Mi,Qianling Zhang,Chuanxin He,Xiangzhong Ren
The precise design and controllable manufacture of electrocatalysts for efficient oxygen reactions (OER and ORR) based on the abundant elements of the earth are urgently required but challenging task. In this study, a CoS 2 /Cu 2 S heterostructured composite (CoS 2 /Cu 2 S-NF) supported by the porous carbon nanofibers is synthesized as a high-efficiency oxygen reaction electrocatalyst. As indicated from in-situ characterization methods (infrared, Raman and XRD) integrated with the density functional theory results, the heterostructures exhibited by CoS 2 and Cu 2 S could be regulated. The results show that the electron transfer/interaction between CoS 2 and Cu 2 S in the heterojunction were regulated, as well as the electronic structures of Co and Cu sites. As impacted by the structural engineering and the electronic modulation, the activity was enhanced, and the performance of electrocatalytic oxygen reactions was improved, which exhibited the lowest potential difference for (ΔE = 0.73 V) compared with commercial electrocatalysts. The liquid ZAB in accordance with on CoS 2 /Cu 2 S-NF exhibited a stable charge and discharge capacity up to 590 h and a great power density reaching 260.60 mW cm −2 . Moreover, the flexible solid-state ZAB based on CoS 2 /Cu 2 S-NF exhibited a great competitive power density (92.06 mW cm −2 ), robust flexibility and an obvious integration. As compared with single metal sulfide-NF, the Density functional theory calculations (DFT) highlight the adsorption on CoS 2 /Cu 2 S-NF side surface in the heterojunction, which more specifically demonstrates the synergistic effect in the junction. This work presents a direction for designing heterostructured junctions as electrocatalyst and moreover its great application potential in rechargeable metal-solid batteries.
研究领域:
电化学
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材料科学
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催化
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能源存储
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Chemistry
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2023
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IF 13.1
Katam Srinivas,Zhuo Chen,Anran Chen,Fei Ma,Ming-qiang Zhu,Yuanfu Chen
The development of efficient single-atom catalysts (SACs) for the oxygen reduction reaction (ORR) remains a formidable challenge, primarily due to the symmetric charge distribution of metal single-atom sites (M-N 4 ). To address such issue, herein, Fe-N x sites coupled synergistic catalysts fabrication strategy is presented to break the uniform electronic distribution, thus enhancing the intrinsic catalytic activity. Precisely, atomically dispersed Fe-N x sites supported on N/S-doped mesoporous carbon (NSC) coupled with FeS@C core-shell nanoparticles (FAS-NSC@950) is synthesized by a facile hydrothermal reaction and subsequent pyrolysis. Due to the presence of an in situ-grown conductive graphitic layer (shell), the FeS nanoparticles (core) effectively adjust the electronic structure of single-atom Fe sites and facilitate the ORR kinetics via short/long-range coupling interactions. Consequently, FAS-NSC@950 displays a more positive half-wave potential ( E 1/2 ) of 0.871 V with a significantly boosted ORR kinetics (Tafel slope = 52.2 mV dec −1 ), outpacing the commercial Pt/C ( E 1/2 = 0.84 V and Tafel slope = 54.6 mV dec −1 ). As a bifunctional electrocatalyst, it displays a smaller bifunctional activity parameter (Δ E ) of 0.673 V, surpassing the Pt/C-RuO 2 combination (Δ E = 0.724 V). Besides, the FAS-NSC@950-based zinc-air battery (ZAB) displays superior power density, specific capacity, and long-term cycling performance to the Pt/C-Ir/C-based ZAB. This work significantly contributes to the field by offering a promising strategy to enhance the catalytic activity of SACs for ORR, with potential implications for energy conversion and storage technologies.
研究领域:
电化学
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材料科学
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能量转换与存储
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）