ELECTROCHIMICA ACTA
·
2019
·
IF 5.383
Haoqing Ji,Mengfan Wang,Sisi Liu,He Sun,Jie Liu,Tao Qian,Chenglin Yan
Pyridinic and graphitic nitrogen are recognized as the most promising dopants for promoting oxygen reactions since they are beneficial to the formation of corresponding C–N bonds as efficient active sites. However, complete control of such efficient nitrogen-doping sites in carbon materials is difficult to realize in practice in a pyrolysis process . Here, we present maximized pyridinic and graphitic nitrogen-doped oxygen electrode via the precise use of nitrogen-containing precursors and carbonization temperature. The critical roles of pyridinic and graphitic nitrogen dopants in enhancing oxygen reaction activity are unraveled and this highly active material exhibits a remarkable half-wave potential of 0.89 V versus the reversible hydrogen electrode (vs. RHE) for oxygen reduction reaction (ORR) and a small potential gap of 0.78 V between ORR and oxygen evolution reaction (OER) in 0.1 M KOH, which is one of the best to date among metal-free bifunctional electrocatalysts . Both zinc-air batteries using liquid electrolytes and the all-solid-state batteries assembled with such air cathodes exhibit excellent cycle performance and reversibility, which can be expressly observed by in-situ X-ray diffraction (XRD) characterization. This nitrogen dopants engineering strategy gives an effective methodology to make full use of nanocarbon materials for their practical applications in next-generation powerful and durable energy devices.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2019
·
IF 3.683
Xuelian Yu,Wenchao Yin,Tao Wang,Yihe Zhang
One of the major challenges associated with fuel cells is exploring highly efficient and low-cost electrocatalysts for the oxygen reduction reaction (ORR). Herein, the feasibility of using Ti3C2 MXene nanoparticles (NPs) to enhance the electrocatalytic activity of g-C3N4 for ORR was investigated. By varying the content of Ti3C2 NPs, a series of g-C3N4/Ti3C2 heterostructures were obtained, displaying enhanced electrocatalytic activity, including a positive shift in both onset and peak potentials toward ORR, compared to the original g-C3N4 in basic solution. We attribute the improvement to the favorable electrical conductivity of well-dispersed Ti3C2 MXene nanoparticles and also enhanced O2 adsorption due to the electronic coupling effect between g-C3N4 and Ti3C2 in the heterostructures. This work demonstrates the potential of earth-abundant MXene family materials to construct low-cost and high-performance electrocatalysts.
研究领域:
材料科学
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电化学
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能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2016
·
IF 3.014
Zhiwei Zhang,Hanning Li,Jie Hu,Baozhong Liu,Qingrui Zhang,Carlos Fernandez,Qiuming Peng
A novel nitrogen-doped biomass carbon/silver (C-N/Ag) composite has been synthesized by a simple method, wherein the precursor of soymilk simultaneously serves as carbon and nitrogen sources, reductant and substrate. The structure, morphology and valence state of samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and X-ray photoelectron spectra. Results show the formation of nano-sized Ag homogenously disperses on the surface of mesoporous substrate, and the self-reduction role mainly attributes to the presence of unsaturated carbon bonding. Electrochemical properties were characterized by galvanostatic discharge and impedance spectra techniques. The sample prepared with 1 mmol AgNO 3 solution, activated by 0.1 M KOH and annealed at 900 °C shows excellent oxygen reduction reaction activity and good electrochemical durability in alkaline medium. The onset potential, limiting diffusion current density and electron transfer number are 0.93 V, 6.26 mA cm −2 and 4.00, respectively, superior to those of 60 wt.% Ag/C and comparable to 20 wt.% Pt/C catalysts correspondingly. The discharge performance of Zn-air batteries is better than that of 20 wt% Pt/C.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2018
·
IF 5.116
Xiaoting Deng,Shaofeng Yin,Xiaobo Wu,Min Sun,Zhiyong Xie,Qizhong Huang
To enhance the activity and durability of platinum (Pt) or platinum-based catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs), fabrication of low-cost platinum catalysts with durable structure is necessary. Here, a series of one-dimensional (1D) platinum-gold/titanium dioxide nanowires (PtAu/TiO 2 NWs) catalysts with different Pt/Au/Ti ratios were synthesized by electrospinning, and the microstructure as well as its electrochemical properties for ORR were investigated. The results illustrate that PtAu/TiO 2 NWs indicate a parabolic-type ORR performance as a function of compositions . The optimized Pt 1 Au 1 /(TiO 2 ) 1 NWs exhibited 4.19 times in mass activity and 2.82 times in SA when compared with commercial Pt on carbon catalyst (20% Pt/C). In addition, the stability test shows that the ECSA of Pt 1 Au 1/ (TiO 2 ) 1 NWs present almost 20% decrease, while the 20%Pt/C drops more than 40% at the same condition. The extraordinary activity of Pt 1 Au 1/ (TiO 2 ) 1 NWs could be attributed to the synergistic effect of TiO 2 and the durability attributed to Au and C skin. The nanowires with larger specific area show that the Pt electronic structure can be changed by the neighbouring TiO 2 , further decreasing the d-band gap to enhance catalytic activity.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2019
·Vol. 9
·期 4
·386
·
IF 3.444
Wenjing Yuan,Fuhua Zhang,Yaoyao Wu,Xiaotao Chen,Chihhsiang Fang,Chuanhao Li
Exploring a novel approach for the synthesis of oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) catalysts with inexpensive and high-activity is desirable. Herein, we report a bubble templating method to synthesize the graphene-like mesoporous carbon sheets with point defects as ORR/HER bifunctional electrocatalysts. The typical product shows excellent ORR performance including the positive onset potential (740 mV) and high diffusion-limiting current density (4.07 mA cm−2). Along with small Tafel slopes, the overpotential is determined to be about −453 and −378 mV at 10 mA cm−2in both alkaline and acidic media, which suggests a good candidate for HER reaction as well. The superior catalytic activities are derived from the abundant point defects on the mesoporous carbon sheets surface, especially the existence of pyridinic and pyrrolic nitrogen species. This study may be an alternative route to prepare the novel functional materials for the applications of ORR and HER.Keywords:bubble templating approach;carbon defect;oxygen reduction;hydrogen evolution
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2017
·Vol. 7
·期 7
·201
·
IF 3.082
Xinxin Jin,Yan Xie,Jiahui Huang
Metal macrocycle based non-noble metal electrocatalysts (NNMEs) with highly efficient oxygen reduction reaction (ORR) activity, good stability, and excellent resistance to the methanol cross-over effect have been regarded as one of the most important alternatives for Pt or Pt based alloys, which are widely used in fuel cells. However, the expensive price of most metal macrocycles hinder further investigation of such a family of NNMEs in large production for practical applications. Here, we introduce a simple strategy to synthesize metal macrocycle based porous carbon (MMPC) material with low cost and easy production of metal macrocycles (hemin (Hm) and vitamin B12(VB12)) as raw materials by using a hard template of MgO. The pyrolysis of MMPC under the optimal temperature at 900 °C shows comparative ORR performance relative to commercial Pt/C, which could be attributed to the large surface area, macro-/mesoporous structure, the carbon layer encapsulating transition metal based oxides, as well as N-doped carbon species. In addition, MMPC (900) displays a better electrochemical property than 20 wt % Pt/C in terms of durability and tolerance to methanol in O2-saturated 0.1 M KOH media.Keywords:metal macrocycle;macro-/mesoporous structure;oxygen reduction reaction;fuel cell
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2018
·Vol. 5
·期 11
·2985-2991
·
IF 5.106
Yunjie Zhou,Yue Sun,Huibo Wang,Cheng Zhu,Jin Gao,Dan Wu,Hui Huang,Yang Liu,Zhenhui Kang
To tackle the issues of high cost, low durability and poor resistance to chemical poisoning of Pt-based materials as cathode catalysts for an oxygen reduction reaction (ORR), an effective method is to design and synthesize heteroatom doped carbon materials, regarded as promising electrocatalysts to replace Pt-based counterparts, due to their low cost, high stability and anti-poisoning ability. The potential of N, B co-doping has been proved by theoretical calculations, and there are still great challenges in the synthesis of such materials. Here, we employ a facile approach to obtain a N, B co-doped carbon material. The resulting material pyrolysed at 1000 °C (NBC-1000) shows excellent ORR activity, exceeding that of the same type of catalysts reported so far. Not only is the NBC-1000 electrocatalyst comparable to the commercial Pt/C in terms of the onset potential, half-wave potential, diffusion limiting current density and electron transfer number, but also it has better durability and methanol tolerance than Pt/C.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2018
·
IF 8.097
Na Cheng,Ling Zhang,Shuying Mi,Hao Jiang,Yanjie Hu,Haibo Jiang,Chunzhong Li
Constructing Pt skin on intermetallics has been confirmed as an efficient strategy to boost oxygen reduction reaction (ORR) kinetics. However, there still lacks a systematic study on revealing the influence of low-Pt-content intermetallic substrates (L12-PtM3). In this paper, Pt skin-encapsulated low-Pt-mole-fraction L12 Cu3Pt has been constructed (denoted as Pt-o-Cu3Pt/C) and compared with its disordered analogue (denoted as Pt-d-Cu3Pt/C). The L12 substrate shows a contracted lattice structure and provides Pt-o-Cu3Pt/C with an excellent specific activity of 1.73 mA cm–2, which is 1.4- and 8.4-fold higher than that of Pt-d-Cu3Pt/C and commercial Pt/C, respectively. Density functional theory calculations reveal that this superior performance is attributed to the more favorable oxygen adsorption energy of surface Pt atoms. Furthermore, the lower formation energy of L12 Cu3Pt combined with the enhanced antioxygenation of Pt provide Pt-o-Cu3Pt/C with a superior durability, showing only a 12.5% loss in mass activity after 5000 potential cycles. Therefore, it is suggested that L12 atomic ordered structure with a low Pt fraction is a promising substrate for building high-performance Pt-skin catalysts for ORR.
研究领域:
材料科学
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ELECTROCHIMICA ACTA
·
2013
·
IF 3.777
Huan Wang,Xiangjie Bo,Yufan Zhang,Liping Guo
Sulfur-doped ordered mesoporous carbons (OMC-S-X) (X = 1, 2 and 3) with different sulfur contents were synthesized as metal-free electrocatalyst for oxygen reduction reaction (ORR). Transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectra (EDX), nitrogen adsorption–desorption, X-ray diffraction (XRD) and X-ray photoelectron spectra (XPS) were employed to confirm the characterizations of OMC and OMC-S. The prepared OMC-S-3 exhibits high electrocatalytic activity, good stability and excellent tolerance to crossover effect for ORR. The high electrocatalytic activity of OMC-S-3 for ORR can be mainly ascribed to the doping of sulfur especially the existence of sulfide groups ( C S C ) which play an important role in promoting the ORR.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 35
·29848-29854
·
IF 3.289
Xiangqian Liu,Weihua Hu
The transition metal iron (Fe) has attracted particular interest in pursuit of low-cost oxygen reduction reaction (ORR) electrocatalysts. Carbon-supported iron oxides and oxyhydroxides have demonstrated promising ORR catalytic activities, but there is limited knowledge regarding the influence of iron species types and their crystalline phases on their ORR activities. In this paper we synthesized four iron/graphene composites with iron oxides (α-Fe2O3, Fe3O4) and oxyhydroxides (α-FeOOH, and α/γ-FeOOH) supported on graphene oxide (GO), and systematically investigated their ORR behaviors. It is found that decorating GO with iron oxides and oxyhydroxides can dramatically improve the ORR activity of pristine GO in alkaline solution in terms of onset potential and current density, and the α-Fe2O3/GO exhibits the highest ORR activity among all four composite materials investigated. This study unveils diverse ORR behaviors on GO-supported iron species, and explores the benchmark of their catalytic performances, and thus provides useful insights into the Fe-enabled high ORR activity for developing efficient transition metal-based ORR electrocatalysts.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2021
·
IF 4.126
Chen Ding,Zijie Mao,Jia-Shun Liang,Xianxian Qin,Qing Zhang,Fan Yang,Qing Li,Wen-Bin Cai
The commercialization of proton exchange membrane fuel cells (PEMFCs) calls for the development of active and durable Pt-based catalysts for oxygen reduction reaction (ORR) by means of a cost-effective and environmentally benign protocol. We report herein an all aqueous phase preparation of carbon supported Au-modified Pt–Co alloy catalyst (Au/Pt–Co/C), which involves the dimethylamine borane co-reduction of aqueous Pt(II) and Co(II) precursors to form a Pt–Co/C catalyst and the ethanol reduction of an aqueous Au(III) precursor to form Au/Pt–Co/C. This Au/Pt–Co/C catalyst not only shows a greatly enhanced ORR activity like the homemade Pt–Co/C and state-of-art Pt–Co/C(com) catalysts as compared to the Pt/C catalyst but also exhibits a much higher durability over the Pt/C(com), homemade Pt–Co/C, and state-of-art Pt–Co/C(com) catalysts in accelerated degradation tests (ADTs) with both half-cell and single-cell configurations. Specifically, the maximum power density of a PEMFC involving the Au/Pt–Co/C cathode suffers only a 6% loss after 30 000 cycles of a standard ADT while that involving the state-of-art Pt–Co/C(com) suffers a 37% loss. This research provides an alternative route to prepare efficient and durable Pt-based ORR catalysts toward a widespread application of PEMFCs.
研究领域:
材料科学
·
化学工程
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Xianwei Li,Shuangxiu Ma,Fang Luo,Zehui Yang
Electrochemical hydrogenerations of nitrogen and oxygen molecules are of significance for nitrogen reduction and oxygen reduction reactions. Strengthening the binding between active sites and gaseous molecules is beneficial for enhancing the catalytic performance, especially in NRR catalysis. In this work, we have engineered the oxygen vacancies in Co 3 O 4 nanoparticles to boost the catalytic activity towards NRR and ORR. Ascribing to the p-d hybridization between Co and N atoms, N 2 electrochemical adsorption is promoted and the related energy barrier of N 2 protonation is significantly decreased by 50%; as a consequence, Faradaic efficiency is 11.2% at −0.4 V vs. RHE, 3-fold higher than Co 3 O 4 /CNT; moreover, due to the oxygen vacancies in Co 3 O 4-x /CNT leading to a higher oxophilicity, Co 3 O 4-x /CNT showed a better selectivity in ORR catalysis and kinetic current density at 0.85 V vs. RHE is boosted by 2.4 times. Consequently, Co 3 O 4-x /CNT exhibits a better rechargeable zinc air battery performance than Pt/C-IrO 2 by a factor of 2.2.
研究领域:
材料科学
·
电化学
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）