scholarly journals Synthesis of Ti4O7/Ti3O5 Dual-Phase Nanofibers with Coherent Interface for Oxygen Reduction Reaction Electrocatalysts

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3142
Author(s):  
Ruyue Shi ◽  
Ying Huang ◽  
Miaoran Li ◽  
Ying Zhu ◽  
Xuexia He ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Catalytic Performance ◽  
Reduction Reaction ◽  
Hydrothermal Growth ◽  
Alkaline Media ◽  
Dual Phase ◽  
Orientation Relationships ◽  
Methanol Tolerance

Electrocatalysts play an important role in oxygen reduction reaction (ORR) in promoting the reaction process. Although commercial Pt/C exhibits excellent performance in ORR, the low duration, high cost, and poor methanol tolerance seriously restrict its sustainable development and application. TinO2n−1 (3 ≤ n ≤ 10) is a series of titanium sub-oxide materials with excellent electrical conductivity, electrochemical activity, and stability, which have been widely applied in the field of energy storage and catalysis. Herein, we design and synthesize Ti4O7/Ti3O5 (T4/T3) dual-phase nanofibers with excellent ORR catalytic performance through hydrothermal growth, which is followed by a precisely controlled calcination process. The H2Ti3O7 precursor with uniform size can be first obtained by optimizing the hydrothermal growth parameters. By precisely controlling the amount of reducing agent, calcination temperature, and holding time, the T4/T3 dual-phase nanofibers with uniform morphology and coherent interfaces can be obtained. The orientation relationships between T4 and T3 are confirmed to be [ 001 ] T 3 / / [ 031 ] T 4 , ( 100 ) T 3 / / ( 92 6 ¯ ) T 4 , and ( 010 ) T 3 / / ( 1 2 ¯ 6 ) T 4 , respectively, based on comprehensive transmission electron microscopy (TEM) investigations. Furthermore, such dual-phase nanofibers exhibit the onset potential and half-wave potential of 0.90 V and 0.75 V as the ORR electrocatalysts in alkaline media, respectively, which illustrates the excellent ORR catalytic performance. The rotating ring-disk electrode (RRDE) experiment confirmed the electron transfer number of 3.0 for such catalysts, which indicates a mixture of two electron and four electron transfer reaction pathways. Moreover, the methanol tolerance and cycling stability of the catalysts are also investigated accordingly.

scholarly journals Enhanced Electrocatalytic Activity and Stability toward the Oxygen Reduction Reaction with Unprotected Pt Nanoclusters

Nanomaterials ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 955 ◽  
Author(s):  
Jing Liu ◽  
Jiao Yin ◽  
Bo Feng ◽  
Tao Xu ◽  
Fu Wang
Keyword(s):  
Carbon Nanotubes ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Specific Activity ◽  
Catalytic Performance ◽  
Reduction Reaction ◽  
Top Down ◽  
Methanol Tolerance ◽  
Pt Nanoclusters ◽  
Mass Activity

The Pt particles within diameters of 1–3 nm known as Pt nanoclusters (NCs) are widely considered to be satisfactory oxygen reduction reaction (ORR) catalysts due to higher electrocatalytic performance and cost effectiveness. However, the utilization of such smaller Pt NCs is always limited by the synthesis strategies, stability and methanol tolerance of Pt. Herein, unprotected Pt NCs (~2.2 nm) dispersed on carbon nanotubes (CNTs) were prepared via a modified top-down approach using liquid Li as a solvent to break down the bulk Pt. Compared with the commercial Pt/C, the resultant Pt NCs/CNTs catalyst (Pt loading: 10 wt.%) exhibited more desirable ORR catalytic performance in 0.1 M HClO4. The specific activity (SA) and mass activity (MA) at 0.9 V for ORR over Pt NCs/CNTs were 2.5 and 3.2 times higher than those over the commercial Pt/C (Pt loading: 20 wt.%). Meanwhile, the Pt NCs/CNTs catalyst demonstrated more satisfactory stability and methanol tolerance. Compared with the obvious loss (~69%) of commercial Pt/C, only a slight current decrease (~10%) was observed for Pt NCs/CNTs after the chronoamperometric measurement for 2 × 104 s. Hence, the as-prepared Pt NCs/CNTs material displays great potential as a practical ORR catalyst.

Nitrogen-doped cobalt phosphate@nanocarbon hybrids for efficient electrocatalytic oxygen reduction

2016 ◽  
Vol 9 (8) ◽  
pp. 2563-2570 ◽  
Author(s):  
Tianhua Zhou ◽  
Yonghua Du ◽  
Shengming Yin ◽  
Xuezeng Tian ◽  
Hongbin Yang ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Catalytic Performance ◽  
Reduction Reaction ◽  
Electron Transfer Pathway ◽  
Nitrogen Doped ◽  
Long Term Stability ◽  
Electrocatalytic Oxygen Reduction

A nitrogen-doped Co3(PO4)2@nanocarbon hybrid was developed as an oxygen reduction reaction (ORR) catalyst and exhibits outstanding catalytic performance with high activity, long-term stability and a four-electron transfer pathway.

Enhancing the oxygen reduction reaction with three-dimensional graphene hollow nanosphere supported single-atomic cobalt catalyst

2020 ◽  
Vol 7 (18) ◽  
pp. 3475-3481
Author(s):  
Ji-Sen Li ◽  
Meng-Jie Huang ◽  
Xiao-Nan Chen
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Cobalt Catalyst ◽  
Three Dimensional ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Hollow Nanosphere ◽  
Methanol Tolerance ◽  
Long Term Stability

Three-dimensional graphene hollow nanospheres supported single-atomic cobalt catalyst shows superior electrocatalytic activity, long-term stability, and excellent methanol tolerance for the oxygen reduction reaction in alkaline media.

Air plasma etching towards rich active sites in Fe/N-porous carbon for the oxygen reduction reaction with superior catalytic performance

2017 ◽  
Vol 5 (32) ◽  
pp. 16605-16610 ◽  
Author(s):  
Wenhua Zhong ◽  
Jiaxiang Chen ◽  
Peixin Zhang ◽  
Libo Deng ◽  
Lei Yao ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Plasma Etching ◽  
Porous Carbon ◽  
Active Sites ◽  
Catalytic Performance ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Air Plasma ◽  
Acidic And Alkaline Media

Plasma etching removed less stable carbons and exposed the active sites in Fe–N/C catalysts which resulted in excellent performances towards the oxygen reduction reaction in both acidic and alkaline media.

scholarly journals Superior FexN electrocatalyst derived from 1,1′-diacetylferrocene for oxygen reduction reaction in alkaline and acidic media

2020 ◽  
Vol 9 (1) ◽  
pp. 843-852
Author(s):  
Hunan Jiang ◽  
Jinyang Li ◽  
Mengni Liang ◽  
Hanpeng Deng ◽  
Zuowan Zhou
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Current Density ◽  
Active Sites ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Acidic Media ◽  
Onset Potential ◽  
Acidic And Alkaline Media ◽  
The Stability

AbstractAlthough Fe–N/C catalysts have received increasing attention in recent years for oxygen reduction reaction (ORR), it is still challenging to precisely control the active sites during the preparation. Herein, we report FexN@RGO catalysts with the size of 2–6 nm derived from the pyrolysis of graphene oxide and 1,1′-diacetylferrocene as C and Fe precursors under the NH3/Ar atmosphere as N source. The 1,1′-diacetylferrocene transforms to Fe3O4 at 600°C and transforms to Fe3N and Fe2N at 700°C and 800°C, respectively. The as-prepared FexN@RGO catalysts exhibited superior electrocatalytic activities in acidic and alkaline media compared with the commercial 10% Pt/C, in terms of electrochemical surface area, onset potential, half-wave potential, number of electrons transferred, kinetic current density, and exchange current density. In addition, the stability of FGN-8 also outperformed commercial 10% Pt/C after 10000 cycles, which demonstrates the as-prepared FexN@RGO as durable and active ORR catalysts in acidic media.

Methanol-Tolerant Oxygen Reduction Reaction at Pt–Pd/C Alloy Nanocatalysts

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
A. Mary Remona ◽  
K. L. N. Phani
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Rotating Disk ◽  
Reduction Reaction ◽  
Rotating Disk Electrode ◽  
Methanol Tolerance ◽  
Pd Catalysts ◽  
Onset Potential ◽  
Direct Methanol ◽  
Methanol Tolerant

Carbon-supported platinum and Pt–Pd alloy electrocatalysts with different Pt/Pd atomic ratios were synthesized by a microemulsion method at room temperature (metal loading is 10 wt %). The Pt–Pd/C bimetallic catalysts showed a single-phase fcc structure and the mean particle size of Pt–Pd/C catalysts was found to be lower than that of Pt/C. The methanol-tolerant studies of the catalysts were carried out by activity evaluation of oxygen reduction reaction (ORR) on Pt–Pd catalysts using a rotating disk electrode (RDE). The studies indicated that the order of methanol tolerance was found to be PtPd3/C>PtPd/C>Pt3Pd/C. The oxygen reduction activities of all Pt–Pd/C were considerably larger than that of Pt/C with respect to onset and overpotential values. The Pd-loaded catalysts shift the onset potential of ORR by 125 mVMSE, 53 mVMSE, and 41 mVMSE to less cathodic potentials for Pt3Pd/C, PtPd/C, and PtPd3/C, respectively, with reference to Pt/C and the Pt3Pd/C catalyst showed greater shift in the onset value than the other PtPd catalysts reported in literature. Moreover, the Pt–Pd/C catalysts exhibited much higher methanol tolerance during ORR than the Pt/C, assessing that these catalysts may function as a methanol-tolerant cathode catalysts in a direct methanol fuel cell.

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