JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2021
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IF 8.128
Xu Lin,Xiaoran Zhang,Zhen Wang,Xinxin Zhu,Jinhui Zhu,Pinsong Chen,Taiyu Lyu,Changzheng Li,Zhi Qun Tian,Pei Kang Shen
Ammonia oxidation reaction (AOR) via electrocatalysis is one of the most efficient ways of utilizing ammonia (a zero-carbon fuel with high hydrogen content) for renewable energy systems. However, AOR seriously suffers from the slow kinetics, and low durability due to its multi-electron transfer process and the poison of the reaction intermediates (N ads and NO ads ) to precious metal catalysts. Herein, hyperbranched concave octahedral nanodendrites of PtIrCu (HCOND) with high-index facets of {5 5 3}, {3 3 1} and {2 2 1} were developed for the first time using a solvothermal method . The HCOND possesses PtIr-rich edges and exhibit highly efficient AOR activity and stability in alkaline media, wherein their onset potential is 0.35 V vs. RHE, which is 60 mV and 160 mV lower than that of the PtIrCu nanoparticles (NPs) (0.41 V) and commercial Pt/C (0.51 V), respectively, and its high mass activity of 40.6 A g PtIr -1 at the 0.5 V vs. RHE is 10.3 times, 2.34 times higher than that of commercial Pt/C (3.9 A g Pt -1 ) and PtIrCu NPs (17.3 A g PtIr –1 ), respectively. In addition, its peak current density (122.9 A g PtIr -1 ) is only reduced by 17.7% after 2000-cycles accelerated durability test. Meanwhile, the performance of PtIrCu HCOND is also better than that of other previously reported morphologies of Pt based catalysts (eg. nanoparticles, nanocubes, nanofilm , nanoflowers). The improvement is critically ascribed to unique advantages of the specific HCOND structure including PtIr rich surface, high-index faceted nanodendrites, strong lattice strain and electronic effects. These characteristics endow the HCOND with great promise to reduce Pt and Ir loading dramatically in the practical application of direct ammonia fuel cells.
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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能源材料
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纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Huanzheng Yang,Xiaoting Huang,Zhihang Liu,Xu Lin,Qiuyan Chen,Jiawang Li,Chenyue Zhang,Zhi Peng Kan,Zhi Qun Tian,Pei Kang Shen
Ammonia has been emerging as a sustainable and environmentally friendly fuel. However, direct electrochemical ammonia oxidation reaction (AOR) in low-temperature fuel cells seriously suffers from high overpotential and deficient durability. Herein, rhombic dodecahedron nanoframe of platinum iridium copper (PtIrCu) with high-index faceted hyperbranched nanodendrites (RDNF-HNDs) was developed using a one-step self-etching solvothermal method . The framework structure with the high-index facets enables the PtIrCu nanocrystals to expose more effective active sites. They exhibit an ultra-low onset potential of 0.33 V vs. RHE and high mass activity of 26.1 A g PtIr –1 at 0.50 V, which is 140 mV lower and 7.5 times higher than that of commercial Pt/C in the AOR. In situ attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy verifies that AOR on PtIrCu RDNF-HNDs prefers to the NH x dimerization pathways, effectively alleviating the poison of N ads and NO x . The theoretical calculation also shows that both introducing Cu atoms into PtIr alloy and increasing the content of Ir in PtIrCu alloy can reduce the reaction energy barrier of electrochemical dehydrogenation from *NH 2 to *NH. The specific structure of PtIrCu RDNF-NDs provides a new inspiration to solve the critical issue of electrocatalysts for AOR with low activity and durability.
研究领域:
材料科学
·
电化学
·
纳米技术
·
催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Yaming Liu,Shanxiang Sheng,Meng Wu,Sen Wang,Yaxin Wang,Hongyue Yang,Jiahao Chen,Xiangyang Hao,Chao Zhi,Yongzhen Wang,Haijiao Xie
Rational design and controllable synthesis of catalysts with unique structure and composition are effective ways to promote electrocatalytic ethanol oxidation, thus contributing the direct ethanol fuel cells to gain ground. Herein, 2.5 nm-thin PtIrCu ternary alloy ultrathin nanowires (UNWs) with high-density planar defects are synthesized via oriented attachment with the assistance of H2. By adjusting the contents of Ir and Cu atoms, we find that the structure of the products changed from nanowires (NWs) to nanoparticles with the increase of Ir content. Density functional theory calculations show that when Cu atoms are replaced by Ir atoms, the vacancy formation energy of Pt atoms is increased, making the Pt atoms difficult to be activated by H2, which is not conducive to the formation of a one-dimensional structure. The optimal Pt43Ir32Cu25 UNWs achieve excellent ethanol electrooxidation reaction activity (1.05 A·mg–1Pt and 1.67 mA·cm–2), for it can significantly reduce the onset potential and improve the ability of CO anti-poisoning. The significant improvement in catalytic performance is attributed to the synergistic effect of the alloy and the NW structure with high-density planar defects.
研究领域:
材料科学
·
电化学
·
催化科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）