用于氧还原反应的碳基负载金属单原子催化剂研究进展

doi:10.15541/jim20200582

摘要/Abstract

摘要：

燃料电池能够将化学能转化为电能, 是一种绿色高效的能量转换装置, 但是受到阴极氧还原反应(ORR)动力学迟缓的限制, 燃料电池需要使用Pt等贵金属作为催化剂, 这就导致其成本显著增加。碳基负载单原子催化剂(C-SACs)展现出高原子利用率和高选择性等优异性能。另外, C-SACs在不同pH环境下都显示出优异的ORR催化活性, 被视为贵金属催化剂的经济替代品。本文介绍了近年来提升C-SACs的 ORR催化性能的策略, 包括选择不同种类的金属中心原子, 调控金属中心的配位结构以及对载体进行杂原子掺杂。同时介绍了这些C-SACs在旋转盘电极和电池器件中的性能。最后对C-SACs在实际应用中的可行性以及潜在的挑战进行了展望和总结。

关键词: 单原子催化剂, 氧还原反应, 配位环境, 杂原子掺杂, 综述

Abstract:

Fuel cells are highly efficient and green devices for direct chemical-to-electrical energy conversion. However, limited by slow kinetics of oxygen reduction reaction (ORR) in cathode, fuel cells require catalysts with noble metal like Pt, thus significantly increasing the cost of the fuel cells. Carbon-supported metal single atom catalysts (C-SACs) have excellent properties such as high atom utilization efficiency and selectivity. In addition, C-SACs show high ORR activity under different pH conditions, hence have been recognized as economical candidates to replace noble metal in fuel cells. This article reviewed the strategies used to improve ORR activity of C-SACs, including selecting different kinds of metal single atoms, tailoring coordination structure of metal centers, and heteroatomic doping to substrate. Performances of C-SACs in rotating disk electrode or battery device are also introduced. At last, the feasibility and potential challenges of C-SACs in practical application are prospected and summarized.

Key words: single atom catalysts, oxygen reduction reaction, coordination environment, heteroatomic doping, review

中图分类号:

O646

郝策, 刘自若, 刘炜, 史彦涛. 用于氧还原反应的碳基负载金属单原子催化剂研究进展[J]. 无机材料学报, 2021, 36(8): 820-834.

HAO Ce, LIU Ziruo, LIU Wei, SHI Yantao. Research Progress of Carbon-supported Metal Single Atom Catalysts for Oxygen Reduction Reaction[J]. Journal of Inorganic Materials, 2021, 36(8): 820-834.

图/表 10

图1 (a)Cu-SA/SNC的HAADF-STEM照片; (b)Cu-SA/SNC 的EXAFS图谱; (c) Cu-SA/SNC的原子结构示意图; (d)各种催化剂的ORR极化曲线; (e)各催化剂在0.85 V时动态电流密度和半波电位的比较; (f)不同锌空气电池的性能测试[31]

Fig. 1 (a) Magnified HAADF-STEM image of Cu-SA/SNC; (b) Ex situFT k3-weighted Cu K-edge EXAFS spectra of Cu-SA/SNC; (c) Schematic interfacial model of Cu-SA/SNC; (d) ORR polarization curves of different catalysts; (e) Kinetic currents at 0.85 V (vs. RHE) and half-wave potentials of Cu-SA/SNC and their references; (f) Performances of Cu-SA/SNC and Pt/C-based Zn-air batteries[31] Colorful figures are available on website

图2 Cu-NGS的合成示意图、结构表征和电化学测试[34]

Fig. 2 Schematic, characterization and electrochemical test of atomically dispersed Cu-Nx site catalyst synthesis[34] (a) Schematic of atomically dispersed Cu-Nx site catalyst synthesis; (b) Cu2p XPS spectra; (c) Steady-state ORR polarization plots;(d) Kinetic currents at 0.78 V (vs. RHE) and half-wave potentials of Cu-NGS and Cu-NG Colorful figures are available on website

图3 (a)Cu ISAS/N-C的形成过程; (b)NC以及(c)Cu ISAS/NC的 AC HAADF-STEM照片; (d)催化剂的ORR极化曲线; (e)不同锌空气电池的性能测试[37]

Fig. 3 (a) Scheme of the formation of Cu ISAS/N-C catalyst; Aberration-corrected high-angle annular dark-field scanning transmission electron microscope (AC HAADF-STEM) images of (b) NC and (c) Cu ISAS/NC; (d) ORR polarization curves and (e) performances of Cu ISAS/NC and Pt/C-based Zn-air batteries[37] Colorful figures are available on website

图4 (a) Mg-N-C的制备过程示意图, (b) HAADF-STEM照片和(c) ORR极化曲线[48]

Fig. 4 (a) Schematic illustration of the synthesis procedure, (b) HAADF-STEM image and (c) ORR polarization curves of Mg-N-C[48] Colorful figures are available on website

图5 Ru-SSC的单原子分布、电化学测试以及探针实验[52]

Fig. 5 Atomic dispersion of Ru-SSC, electrocatalytic tests towards ORR and probe experiment[52] (a) High-resolution HAADF-STEM image of Ru-SSC; (b) EXAFS fitting curve for Ru-SSC;(c) ORR polarization curves of the synthesized catalysts; (d) Specific activity and mass activity comparison among Ru-SSC, Pt/C, and Fe-SSC; (e) Reaction between ROS and ABTS (top) and photographs showing the color change of the solution after Fenton reaction (bottom); (f) ORR polarization plots before and after potential cycling stability tests Colorful figures are available on website

图6 (a) Pt1-N/BP的HAADF-STEM照片; (b)样品的XANES, (c) EXAFS谱和(d) ORR极化曲线[60]

Fig. 6 (a) HAADF-STEM image of Pt1-N/BP, (b) Pt L3-edge XANES, k2-weighted R-space FT spectra from (c) EXAFS, (d) ORR polarization curves for all samples[60] Colorful figures are available on website

图7 Fe-N/P-C的制备过程示意图(a)及其电化学性能表征(b, c)[65]

Fig. 7 (a) Schematic diagram of Fe-N/P-C preparation and (b, c) corresponding electrochemical performances[65] Colorful figures are available on website

图8 Fe-SAs/NSC, Co-SAs/NSC 以及Ni-SAs/NSC的结构表征[70]

Fig. 8 Structural characterizations of Fe-SAs/NSC, Co-SAs/NSC and Ni-SAs/NSC[70] The normalized XANES spectra and the k3-weighted Fourier transform of EXAFS spectra at (a,b) Fe K-edge of Fe-SAs/NSC and the reference materials, (d,e) Co K-edge of Co-SAs/NSC and the reference materials, and (g,h) Ni K-edge of Ni-SAs/NSC and the reference materials with insets showing the enlarged boxed area in the same picture; EXAFS curves between the experimental data and the fit of (c) Fe-SAs/NSC, (f) Co-SAs/NSC, and (i) Ni-SAs/NSC with insets showing the fitted structures; (j) Schematic illustration of the formation of Fe-SAs/NSC, Co-SAs/NSC, and Ni-SAs/NSC with different coordination environments Colorful figures are available on website

图9 (a)Cu-SA/NC(meso)制备过程的示意图; Cu+-SA/NC(meso)-7的(b)SEM照片, (c)TEM照片和(d)选区电子衍射图像; (e)Cu-SA/NC(meso)的高分辨率XPS图谱; (f)Cu+-SA/NC(meso)-7以及对比样品在0.1 mol/L KOH中的LSV曲线; (g)Cu-SA/NC(meso)催化剂ORR活性的比较[74]

Fig. 9 (a) Formation process of Cu-SA/NC(meso) catalysts; (b) SEM image, (c) TEM image, and (d) corresponding SAED pattern of Cu +-SA/NC(meso)-7; (e) Cu2p high-resolution XPS surveys of Cu-SA/NC (meso) catalysts; (f) Linear sweep voltammetry (LSV) curves of Cu+-SA/NC (meso)-7 and comparison samples; (g) Comparison of ORR activities for Cu-SA/NC (meso) catalysts[74] Colorful figures are available on website

图10 Mn-N2C2的制备过程示意图以及结构表征[75]

Fig. 10 Formation process and structural characterizations of Mn-N2C2[75] (a) Illustration of the formation of MnSAC; (b, c) HAADF-STEM images of MnSAC; (d) iR-corrected ORR polarization curves for MnSAC, CN, and 20% Pt/C; (e) Mn K-edge XANES and (f) FT EXAFS spectra of MnSAC and their references; (g) Atomic structure model for MnSAC Colorful figures are available on website

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