The influence of heteroatom doping on the performance of carbon-based electrocatalysts for oxygen evolution reactions
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摘要: 近年来,由于能源的过度消耗和环境污染,各类可再生的能源转换和存储设备得到广泛研究。设计高效的电催化剂是提高能源转换效率的关键。了解分析电催化剂,尤其是非金属掺杂的碳基电催化剂的作用机理对其应用有着至关重要的作用。目前很少有评论更详细地总结和分析杂原子掺杂导致的OER活性改善的机制。本文总结包括N、P、S和B在内的非金属掺杂的碳基电催化剂,并分析改善其电催化性能的作用机制。进一步总结二元或者多元共掺杂碳基材料电催化剂及作用机理,提出其未来所需要解决的问题以及发展方向。Abstract: Various types of energy conversion and storage devices have been developed in recent years to tackle with the problems of the over-consumption of fossil fuels and the environmental pollution they cause. The oxygen evolution reaction (OER) is the key half-cell reaction of many energy conversion and storage devices. The influences of the heteroatom doping of metal-free carbon-based electrocatalysts with N, P, S or B and co-doping with N/P or N/S on their performance as OER electrocatalysts are reviewed. Doping methods to prepare metal-free carbon-based electrocatalysts are summarized, and problems that need to be solved are discussed and challenges for future research are proposed.
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Key words:
- Electrocatalysts /
- Carbon materials /
- Doping /
- Oxygen evolution reaction
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Figure 3. (a) SEM image of N-CNTs on the quartz substrate. (b) Diagram of theoretical charge distribution density of N-CNTs (Reproduced with permission[40], Copyright 2009, American Association for the Advancement of Science). (c) Diagram of preparation of polymer@CNT composite films. (d) OER polarization curves of polymer@CNT composite films (1 mol·L−1 KOH) (Reproduced with permission[43], Copyright 2017, Royal Society of Chemistry).
Figure 4. (a) Synthesis diagram of composite O-N-CNs. (b) LSV curves of O-CSs, O-N-CNs and Pt/C (0.1 mol·L−1 KOH, O2-saturated, 10 mV·s−1) (Reproduced with permission[45], Copyright 2018, American Chemical Society). (c) Schematic diagram of preparation of composite NCNs. (d) SEM image of NCN-1000-5. (e) The OER performance curves of NCNs (0.1 mol·L−1 KOH, O2-saturated, 1600 r·min−1, 5 mV·s−1). (f) The top and front views of the active site of OER when *OOH is adsorbed (Reproduced with permission[46], Copyright 2018, Royal Society of Chemistry). (g) Synthesis diagram of NDGs composites. (h) Seven possible types of pyridinic-N sites in the graphene model. (i) Volcano diagram between the adsorption energy of *OH and the overpotential in OER without considering the influence of PH. Gray, blue, and white balls represent the C, N, and H atoms, respectively (Reproduced with permission[48], Copyright 2018, American Chemical Society).
Figure 5. (a) Schematic diagram of the reaction process of oxygen-rich defective graphene materials. (b) In-situ XRD and (c) in-situ Raman spectra of O-NGM-800 catalyzed zinc-air batteries during discharge and charge (Reproduced with permission[51], Copyright 2019, Wiley-Blackwell).
Figure 6. (a) SEM image of PDGLs. (b) Path diagram of C―O―P=O(OH)2 group with pentagonal defect for OER. (c) Schematic diagram of the possible formation of a stable pentagonal defect structure in C―O―P=O(OH)2 group when C―P was fractured (Reproduced with permission[78], Copyright 2020, Wiley-VCH Verlag). (d) Flow chart of preparation of phosphorus-doped graphene (G-P) by ball milling. (e) SEM image of the G-P. (f) The LSV and (g) Tafel curves of composites (Reproduced with permission[79], Copyright 2016, Royal Society of Chemistry). (h) Preparation diagram of 2D-PPCN. (i) SEM image of 2D-PPCN. (j) Potential difference of ORR and OER bifunctional electrocatalysts for different electrocatalysts. (k) The OER polarization curves of the samples (1600 r·min−1, 0.1 mol·L−1 KOH, 10 mV·s−1) (Reproduced with permission[80], Copyright 2018, American Chemical Society).
Figure 7. (a) Synthesis diagram of G-CS2 prepared by the CS2 method. (b) LSV curves of the samples (0.1 mol ·L−1 KOH, 5 mV·s−1, 1600 r·min−1) (Reproduced with permission[87], Copyright 2019, Elsevier Ltd). (c) Schematic diagram of preparation process of SDGNs. (d) TEM image of SDGNs. (e) The OER polarization curves of SDGNs (10 mV·s−1, 1600 r·min−1) (Reproduced with permission[88], Copyright 2019, Elsevier Ltd). (f) The SEM image of B-doped g-C3N4 nanosheets. (g) OER polarization curves and (h) Tafel curves of pure g-C3N4 and B-doped g-C3N4 (0.1 mol·L−1 KOH, 5 mV·s−1, 1600 r·min−1) (Reproduced with permission[102], Copyright 2018, Chinese Society of Metals).
Figure 8. (a) Synthesis diagram of N/P-HCNFs. (b) OER polarization curves of N/P-HCNFs, Pt/C, IrO2 (0.1 mol·L−1 KOH, 1600 r·min−1) (Reproduced with permission[107], Copyright 2019, Elsevier BV). (c) Preparation diagram of EBP@NG (Reproduced with permission[108], Copyright 2019, American Chemical Society). (d) Preparation flow chart of SWCNT@NPC. (e) The schematic diagram of different active sites of N/P-HCNFs for OER/ORR. (f) OER polarization curves of SWCNT@NPC, Pt/C, Ir/C (O2, 0.1 mol·L−1 KOH) (Reproduced with permission[106], Copyright 2018, Elsevier Ltd).
Figure 9. (a) SEM image of C-PDA/S. (b) The OER polarization curves of C-PDA/S, C-PDA, and RuO2 (0.1 mol·L−1 KOH) (Reproduced with permission[110], Copyright 2020, Elsevier BV). (c) The schematic diagram of the process of preparing N/S-doped porous carbon materials by a one-pot method (Reproduced with permission[29], Copyright 2017, Royal Society of Chemistry). (d) Preparation diagram of SHG. (i) Mixing melamine-nickel sulfate complex and KCl by ball milling. (ii) Annealing to obtain Ni-KCl@SHG. (iii) Etching Ni@KCl and KCl and then reheat annealing to obtain SHG. (e) The OER polarization curves and (f) the onset potential of SHG, GC, GS and RuO2 (0.1 mol·L−1 KOH) (Reproduced with permission[42], Copyright 2017, Wiley-Blackwell).
Table 1. A summary of recent research progress in the metal-free doped carbon-based electrocatalysts.
Material Electrolyte Eonset (mV vs. RHE) a Ej (mV vs. RHE) b Ref. PEMAc@CNTs 1 mol·L−1 KOH - 298 [35] O-N-CNs 0.1 mol·L−1 KOH - 381 [37] NCN-1000-5 0.1 mol·L−1 KOH 320 410 [38] NCNF-1000 0.1 mol·L−1 KOH 200 610 [39] NDGs-800 1 mol·L−1 KOH - 450 [41] PDGLs3 0.1 mol·L−1 KOH - 230 [55] PCN-CFP 0.1 mol·L−1 KOH - 400 [51] G-P 1 mol·L−1 KOH - 330 [56] 2D-PPCN-2/6 0.1 mol·L−1 KOH - 365 [57] SDGN (5) 0.1 mol·L−1 NaOH - 500 [65] N, P-HCNF-8 0.1 mol·L−1 KOH - 320 [84] EBP@NG (1:8) 1 mol·L−1 KOH - 310 [85] PNGF (op) - - 320 [82] SWCNT@NPC 0.1 mol·L−1 KOH - 448 [83] C-PDA/S 0.1 mol·L−1 KOH - 550 [88] 1100-CNS 0.1 mol·L−1 KOH - 460 [24] N, S-CN 0.1 mol·L−1 KOH - 414 [80] SHG 0.1 mol·L−1 KOH 260 330 [34] BP-S 1 mol·L−1 KOH - 310 [93] SNC 0.1 mol·L−1 KOH - 440 [89] N-CNSP 1 mol·L−1 KOH - 390 [59] NF@CB 0.1 mol·L−1 KOH 179 379 [60] HHPC 0.1 mol·L−1 KOH 150 380 [61] NCC-700 1 mol·L−1 KOH - 464 [62] N, F-GQDs 1 mol·L−1 KOH - 400 [63] PCP-800 0.1 mol·L−1 KOH - 440 [64] SNCs 0.1 mol·L−1 KOH - 440 [65] N, P-GC-1000 1 mol·L−1 KOH - 330 [66] N/E-HPC-900 0.1 mol·L−1 KOH 200 380 [67] BP-S 1 mol·L−1 KOH 310 410 [68] CCC-PAN 1 mol·L−1 NaOH - 351 [69] NFPGNS 1 mol·L−1 KOH 220 340 [70] P, S-CNS 0.1 mol·L−1 KOH 30 330 [71] P-CC 1 mol·L−1 KOH - 450 [72] NG10 0.1 mol·L−1 KOH 290 510 [73] N-doped GNSs 1 mol·L−1 KOH 270 - [74] GO-PANi31-FP 0.1 mol·L−1 KOH 390 520 [41] N-MGF 0.1 mol·L−1 KOH - 402 [75] NCMT-1000 0.1 mol·L−1 KOH - 290 [76] N, P-GCNS 0.1 mol·L−1 KOH 90 340 [77] Note: a, b: Eonset and Ej represent the onset potential and the overpotential at the current density of 10 mA·cm−2 respectively. -
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