FUEL
·
2019
·
IF 5.128
Rongbin Li,Kai Wei,Qian Huang,Hongde Xia
The unburnt carbon content of fly ash is an important index for evaluating the combustion efficiency of boilers. Measurement by traditional loss-on-ignition (LOI), approximate and elemental analyses causes large errors due to mixing minerals such as portlandites, carbonates, or sulfates with the unburnt carbon. In this paper a new method of Equivalent Characteristic Spectrum Analysis (ECSA®) based on Thermogravimetric Mass Spectrometry (TG-MS) was adopted to determine the unburnt carbon in fly ash. The measuring mechanism, accuracy, superiority, sensitivity, and reliability of ECSA® were discussed. The intrinsic measuring mechanism of ECSA® and its sensitivity were explored through analyzing the reaction characteristics of model compounds that were used to simulate the real fly ash. Five types of real fly ashes collected from boiler plants were used to calibrate and verify the reliability and accuracy of ECSA® method. The ECSA® was finally validated to be more precise and accurate by improving 2 to 3 orders of magnitude in error compared with the LOI and elemental analysis on determining the unburnt carbon in fly ash, and can provide reliable information to assess the operating status of boilers.
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DOI
高影响因子
INORGANIC CHEMISTRY
·
2022
·
IF 5.436
Yongsheng Wang,Xinyu Wang,Lipeng Zhang,Yufeng Zhang,Zhaoxiang Xu,Lianyue Lu,Junling Huang,Likun Yin,Wei Zhu,Zhongbin Zhuang
Iron phosphide nanoparticles (NPs) are promising noble metal-free electrocatalysts for the hydrogen evolution reaction (HER), but they usually show inferior activity due to the limited surface area and oxidative passivation. We reported a facile synthetic method to prepare FeP hollow NPs (HNPs) with various precursors. It was proven that the structural parameters (i.e., size, phosphating temperature, phase, and surfactant) of oxide precursors were correlated to the electrochemically active surface area (ECSA), phase purity, surface oxidation, and hollow morphology of FeP HER catalysts, thus affecting the HER activity. Among the three FeP HNPs, the 9 nm FeP HNPs prepared using the Fe3O4 precursor exhibited the highest overall activity with the lowest overpotential of 76 mV to drive a cathodic current density of 10 mA·cm–2 due to the highest ECSA, while 25 nm FeP prepared using the Fe2O3 precursor showed the highest turnover frequency because of the high phase purity and low surface oxidation degree.
研究领域:
材料科学
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电化学
·
催化
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产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2023
·
IF 22.1
Yue Shi,Shuanglong Zhou,Jiaxin Liu,Xin Zhang,Jiao Yin,Tianrong Zhan,Yu Yang,Guangjiu Li,Jianping Lai,Lei Wang
Developing integrated non-noble metal electrocatalysts with mass activity comparable to noble metal is a significant challenge for overall water splitting. Herein, we constructed an integrated amorphous cobalt phosphoselenide (a-CoPSe) electrode via amorphization and dual anion-mediated strategy, achieving a significant improvement in the electrochemical active surface area (ECSA) and turnover frequency (TOF). The a-CoPSe offers large ECSA (65.9 m 2 g −1 ) and high TOF values of 35.7 s −1 for hydrogen evolution reaction (HER) and 31.9 s −1 for oxygen evolution reaction (OER) at 300 mV. The mass activities of a-CoPSe are 890.4 A g −1 Co for HER at 300 mV and 677.4 A g −1 Co for OER at 250 mV, which are comparable to commercial Pt/C (10014.6 A g −1 ) and RuO 2 (232.6 A g −1 ). Theoretical calculation reveals amorphous cobalt with balanced charges regulated by phosphorus and selenium atoms simultaneously facilitate H 2 O* , H* , OH* and OOH* adsorption, which greatly promotes the HER and OER kinetics.
研究领域:
材料科学
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电化学
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催化
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2023
·
IF 4.5
Shixin Zhang,Huanqiao Song,Tianjiao Li,Mingsheng Luo,Yu Chen,Changke Shao
Developing catalysts for the stable electrooxidation of ethanol have been a goal pursued by scientists. The present work reports a facile synthesis of catalysts with a double junction structure of Pt and SnO 2 on graphene (Pt/SnO 2 GN) through sol–gel combined with glycol hydrothermal reduction method. The physicochemical analyses show that the reduced Pt uniformly dispersed on GN is located adjacent to SnO 2 and has electronic interaction with the composite carrier. The electrochemical results exhibit that Pt/SnO 2 GN has better catalytic performance for ethanol electrooxidation than PtSnO 2 /GN and PtSn/GN. The ethanol oxidation peak current density on Pt/SnO 2 GN, after 1500 cycles of voltammetric testing, can still maintain 99.2% of the highest. The excellent catalytic stability of Pt/SnO 2 GN is ascribed to the double junction structure and the appropriate interaction between Pt and SnO 2 on GN, which enlarge the ECSA of Pt, improve the structural integrity, accelerate the charge transfer kinetics and increase the CO tolerance.
研究领域:
电化学
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催化
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
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IF 8.128
Jianmei Cen,Pei Kang Shen,Yanfei Zeng
Herein, a novel Ru-doped bimetal phosphide (Ru-NiCoP) heterostructure electrocatalyst on Ni foam is successfully synthesized through a multi-step hydrothermal reaction , ion exchange, and phosphorization method for efficient overall water splitting in alkaline media. The doping of Ru and P can effectively optimize the electronic structure and expose more active sites. The unique 3D interconnected nanowires not only ensures the uniform distribution of Ru coupled with NiCoP, but also endows the Ru-NiCoP/NF with the large ECSA, the fast electron transport and the favorable reaction kinetics attributes. Benefiting from the compositional and structural advantages, Ru-NiCoP/NF catalyst exhibits significantly enhanced catalytic activities along with excellent stability, only needing 32.3 mV at 10 mA cm −2 for HER and 233.8 mV at 50 mA cm −2 for OER . In particular, when Ru-NiCoP/NF is employed as both cathode and anode electrodes, a small voltage of 1.50 V is required to reach 30 mA cm −2 for overall water splitting with an impressive stability. This study provides an alternative strategy on the design and development of high performance catalysts for overall water splitting and other energy conversion fields.
研究领域:
材料科学
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电化学
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催化
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能源转换
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DOI
PubMed
高影响因子
RSC Advances
·
2023
·Vol. 13
·期 6
·3835-3842
·
IF 3.9
Tanlun Wang,Lincheng Xu,Chenxiang Sun,Xiyuan Li,Yong Yan,Fan Li
Fe–N–C has a high number of FeNx active sites and has thus been regarded as a high-performance oxygen reduction reaction (ORR) catalyst, and combining Fe3C with Fe–N–C typically boosts ORR activity. However, the catalytic mechanism remains unknown, limiting further research and development. In this study, a precipitation-solvothermal process was used in conjunction with pyrolysis to produce a series of Fe–N–C catalysts derived from a zeolitic imidazolate framework (ZIF) that was composited with Fe3C. The prepared catalysts had a multiscale structure of ZIF-like carbon particles and rod-like structures, as well as bamboo-like carbon nanotubes (CNTs) and carbon layers wrapped with Fe3C particles while a series of studies revealed the origin of the rod-like structures and Fe3C phase. The hierarchical structure was beneficial to the enhanced electrocatalytic performance of catalysts for ORR. The optimal sample had the highest half-wave potential of 0.878 V vs. RHE, which was higher than that of commercial Pt/C (0.861 V vs. RHE). The ECSA of the optimal sample was 1.08 cm2 μg−1, with an electron transfer number close to 4, and functioning kinetics. The optimal sample exhibited high durability and methanol tolerance for the ORR. Finally, blocking different Fe active sites with coordination ions demonstrated that Fe(II) was the main active site, indicating that Fe3C primarily served as a cocatalyst to optimize the electron structure of Fe–N–C, thereby synergistically improving the ORR activity.
研究领域:
材料科学
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电化学
·
催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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