Journal of Materials Chemistry A
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2023
·Vol. 11
·期 12
·6191-6197
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IF 11.9
Hongzhou Yang,He Huang,Qing Wang,Lu Shang,Tierui Zhang,Shouguo Wang
3d transition metal single atom catalysts (SACs) (e.g. M = Fe, Co, Cu) are considered as promising catalysts for oxygen reduction reaction (ORR), among which Fe SACs display comparable performance to commercial Pt/C. However, Fe SACs still demand significant improvements in activity and stability for further industrial deployment. Herein, a Fe, Cu dual metal SAC was synthesized using a facile ligand-mediated method. Fe and Cu atoms were atomically dispersed on commercial carbon black in the form of FeN4 and CuN4 sites. Owing to the interactions between the adjacent Fe and Cu atoms co-existing in a very tiny area, the as-synthesized Fe, Cu dual metal SAC exhibited excellent ORR performance with a high half-wave potential of 0.926 V and good stability in 0.1 M KOH, which are significantly higher than that of the Fe-SAC or Cu-SAC control samples. Density function theory calculations showed that the Cu single atom can act as an electron donator enriching the electron density of Fe sites, thus endowing the Fe sites with optimized adsorption/desorption energy for ORR intermediates and thereby facilitating the ORR activity of FeCu-SAC. Moreover, a study on three typical commercial carbon substrates indicated that carbon support with high surface areas and hierarchical pore structure was beneficial for ORR. The excellent ORR activity and durability of FeCu-SAC enabled the constructed Zn–air battery to have a high power density of 201.4 mW cm−2 and high specific energy of 827.68 W h kg−1.
研究领域:
材料科学
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催化化学
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2024
·
IF 15.7
Yuan Jiang,Ji Yang,Mu-Lin Li,Xue-Jia Wang,Na Yang,Wei-Ping Chen,Jin-Chao Dong,Jian-Feng Li
ABSTRACT Metal-nitrogen-carbon single-atom catalysts (M-N-C SACs) have emerged as a highly promising material for ammonia synthesis from electrocatalytic nitrate reduction due to their isolated metal site and capacity to prevent the N–N coupling. However, understanding the structure-activity relationship at molecular level remains challenging because of the inhomogeneous M N x structure presented in current synthesized M-N-C catalysts. In this study, we utilized metal phthalocyanine ( M Pc) as a model platform catalyst containing a uniform and well-defined M N 4 center to unravel their intrinsic activity tendency toward ammonia synthesis from nitrate reduction, both experimentally and theoretically. Our experimental results exhibit a significant activity difference for ammonia production in the order of FeN 4 > CuN 4 > NiN 4 > MnN 4 > CoN 4 > ZnN 4 , and among which the FeN 4 site delivers much higher faradic efficiency and the highest turnover frequency of 83.3% and 4395.2 h –1 at –1.0 V vs . RHE, respectively. Density-functional theory calculations indicates that, compared to CoN 4 and MnN 4 , the FeN 4 site not only has appropriate adsorption strength for NO x intermediate species, but also has certain inhibitory effects on hydrogen evolution reaction process. These findings provide systematic and reliable guidance for catalyst synthesis toward nitrate reduction to NH 3 from both the experimental and computational perspectives.
研究领域:
催化
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电化学
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材料科学
·
理论化学
✓ 已验证
DOI
高影响因子
Journal of Energy Chemistry
·
2023
·
IF 13.1
Jing Zhang,Jia-Jun Dai,De-Quan Cao,Heng Xu,Xing-Yu Ding,Chun-Hua Zhen,Beate Paulus,Jin-Yu Ye,Qian Liang,Jun-Ke Liu,Shi-Jun Xie,Sai-Sai Deng,Zhen Wang,Jun-Tao Li,Yao Zhou,Shi-Gang Sun
With tunable local electronic environment, high mass density of MN 4 sites, and ease of preparation, metal–organic conjugated coordinative polymer (CCP) with inherent electronic conductivity provides a promising alternative to the well-known M−N−C electrocatalysts. Herein, the coordination reaction between Cu 2+ and 1,2,4,5-tetraaminobenzene (TAB) was conducted on the surface of metallic Cu nanowires, forming a thin layer of CuN 4 -based CCP (Cu-TAB) on the Cu nanowire. More importantly, interfacial transfer of electrons from Cu core to the CuN 4 -based CCP nanoshell was observed within the resulting CuTAB@Cu, which was found to enrich the local electronic density of the CuN 4 sites. As such, the CuTAB@Cu demonstrates much improved affinity to the *COOH intermediate formed from the rate determining step; the energy barrier for C–C coupling, which is critical to convert CO 2 into C 2 products, is also decreased. Accordingly, it delivers a current density of −9.1 mA cm −2 at a potential as high as −0.558 V (vs. RHE) in H-type cell and a Faraday efficiency of 46.4% for ethanol. This work emphasizes the profound role of interfacial interaction in tuning the local electronic structure and activating the CuN 4 -based CCPs for efficient electroreduction of CO 2 .
研究领域:
材料科学
·
电化学
·
催化
·
能量转换
✓ 已验证
产品关联
DOI
高影响因子
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