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OER nanoparticles

Xueting Feng, Qingze Jiao, Huiru Cui, Mengmeng Yin, Qun Li, Yun Zhao, Hansheng Li, Wei Zhou, Caihong Feng
The oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are considered to be cornerstones of many energy conversion and storage technologies. It is difficult study high-performance non-precious materials as cost-effective bifunctional electrocatalysts for both the OER and ORR in future practical applications. In this study, NiCo2S4 hollow spheres (NiCo2S4 HSs) were fabricated via an effective and facile one-pot "green" approach in an N,N-dimethylformamide (DMF) - ethylene glycol (EG) binary solution...
August 13, 2018: ACS Applied Materials & Interfaces
Guoqiang Liu, Cuijiao Zhao, Guozhong Wang, Yunxia Zhang, Haimin Zhang
We investigate the possibility of utilizing benzyl alcohol oxidation reaction to replace sluggish oxygen evolution reaction (OER) for the charging process in a rechargeable zinc-air battery, catalyzed by NiCo alloy nanoparticles supported on activated carbon (NiCo/AC) with the multifunctional electrocatalytic activities of the oxygen reduction, oxygen evolution and benzyl alcohol oxidation reactions. As an electrocatalyst for the oxygen reduction reaction (OER), NiCo/AC exhibits superior catalytic activity with an onset potential of 0...
July 29, 2018: Journal of Colloid and Interface Science
Lucy Gloag, Tania M Benedetti, Soshan Cheong, Richard F Webster, Christopher E Marjo, J Justin Gooding, Richard D Tilley
For Ru nanoparticles to be effective oxygen evolution reaction (OER) catalysts an approach is needed that stabilizes Ru while retaining high activity. Here, we present a synthesis for Pd-Ru core-shell nanoparticles with tunable shell thicknesses between 0.3-1.2 nm. The Pd core stabilizes the Ru shell to increase the stability by up to 10×, while maintaining the high current densities of pure Ru nanoparticles. Results show that the activity and stability of the nanoparticles is highly dependent on the nanoparticle shell thickness, with thin Ru shells and full coverage of the Pd core being vital for increasing both activity and stability...
August 3, 2018: Nanoscale
Qin Wang, He Miao, Shanshan Sun, Yejian Xue, Zhaoping Liu
Flexible rechargeable zinc-air batteries are considered as one of the most promising power supplies for the emerging flexible and wearable electronic devices. However, the development of flexible zinc-air battery is stagnant due to the lacks of efficient bi-functional catalysts with high oxygen catalytic activity and flexible solid-state electrolyte with high mechanical stability and ionic conductivity. In this work, Co3O4/Ag@NrGO composite is synthetized by a facile one-pot method, and the catalyst shows remarkable ORR/OER bi-functional catalytic activity and good long-term stability...
July 31, 2018: Chemistry: a European Journal
Ho-Wing Man, Chui-Shan Tsang, Molly Meng-Jung Li, Jiaying Mo, Bolong Huang, Lawrence Yoon Suk Lee, Yun-Chung Leung, Kwok-Yin Wong, Shik Chi Edman Tsang
Foreign transition metals are doped into the hexagonal nickel phosphide structure through a simple and facile bottom-up wet-chemical synthesis process via stabilization with oleylamine, trioctylphosphine (TOP), and trioctylphosphine oxide (TOPO): the as-prepared transition metal-doped nickel phosphide nanoparticles show a high level of doping but create no significant distortion of the crystal structure and morphology against pristine nickel phosphide nanoparticles, which exhibit excellent activity in the electrochemical oxygen evolution reaction (OER), having overpotential as small as 330 mV at 20 mA cm-2 with a low Tafel slope value of 39 mV dec-1 ...
August 11, 2018: Chemical Communications: Chem Comm
Hao Zhang, Jiaying Xu, Yiwen Jin, YinLin Tong, Qingyi Lu, Feng Gao
Two-dimensional (2D) materials refer to a class of materials with high electrical conductivity along 2D conducting channels and possessing abundant active sites in the form of surface atoms and edge sites, representing promising candidates for high-performance fuel cells and water splitting electrocatalysts. Herein, we report an ammonia-modulating method for the synthesis of nanosized bimetallic ZnCo-ZIF, and owing to quantum effect the nanosized ZnCo-ZIF can be transformed into a novel two-dimensional nanosheet-arrays as bi-functional electrocatalysts...
July 17, 2018: Chemistry: a European Journal
Zhengcui Wu, Zexian Zou, Jiansong Huang, Feng Gao
Constructing catalysts with new and optimizational chemical components and structures, which can operate well for both the anodic oxygen evolution reaction (OER) and the cathodic hydrogen evolution reaction (HER) at large current densities, is of primary importance in practical water splitting technology. Herein, the NiFe2 O4 nanoparticles/NiFe layered double hydroxide (LDH) nanosheet heterostructure array on Ni foam was prepared via a simple one-step solvothermal approach. The as-prepared heterostructure array displays high catalytic activity toward the OER with a small overpotential of 213 mV at 100 mA cm-2 and can afford a current density of 500 mA cm-2 at an overpotential of 242 mV and 1000 mA cm-2 at 265 mV...
July 25, 2018: ACS Applied Materials & Interfaces
Jongsik Park, Taehyun Kwon, Jun Kim, Haneul Jin, Ho Young Kim, Byeongyoon Kim, Sang Hoon Joo, Kwangyeol Lee
While the realization of clean and sustainable energy conversion systems primarily requires the development of highly efficient catalysts, one of the main issues had been designing the structure of the catalysts to fulfill minimum cost as well as maximum performance. Until now, noble metal-based nanocatalysts had shown outstanding performances toward the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). However, the scarcity and high cost of them impeded their practical use...
July 16, 2018: Chemical Society Reviews
Jaison Joy, Sivamathini Rajappa, Vijayamohanan K Pillai, Subbiah Alwarappan
In this work, we report a one-pot solvothermal strategy to synthesize Co3 Fe7 incorporated graphene nanoribbons (Co3 Fe7 ). An improved bi-functional electrocatalytic activity over the traditional electrocatalysts is exhibited by the Co3 Fe7 /nitrogen-doped graphene nanoribbon (NGNR) composite. For instance, this composite Co3 Fe7 /NGNRs depicted a lower overpotential of 350 mV than NGNRs (380 mV) and IrO2 (450 mV) to sustain 10 mA cm-2 for an oxygen evolution reaction in 1.0 M KOH. Furthermore, during an oxygen reduction reaction, the catalyst exhibited a four-electron pathway and it is interesting to note that its electrocatalytic behavior is on a par with commercial Pt/C...
July 13, 2018: Nanotechnology
Pan Peng, Xiao-Min Lin, Yuzi Liu, Alexander S Filatov, Dongguo Li, Vojislav R Stamenkovic, Dali Yang, Vitali B Prakapenka, Aiwen Lei, Elena V Shevchenko
Low-cost transition metal oxides are actively explored as alternative materials to precious metal-based electrocatalysts for the challenging multistep oxygen evolution reaction (OER). We utilized the Kirkendall effect allowing the formation of hollow polycrystalline, highly disordered nanoparticles (NPs) to synthesize highly active binary metal oxide OER electrocatalysts in alkali media. Two synthetic strategies were applied to achieve compositional control in binary transition metal oxide hollow NPs. The first strategy is capitalized on the oxidation of transition-metal NP seeds in the presence of other transition-metal cations...
July 25, 2018: ACS Applied Materials & Interfaces
Duan Bin, Beibei Yang, Chao Li, Yao Liu, Xiao Zhang, Yonggang Wang, Yongyao Xia
Developing low-cost catalysts for electrochemical oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) with superior performance in an alkaline solution is of significance for large-scale applications in aqueous zinc-air batteries (ZABs). Herein, we describe the in situ design of embedded NiFe nanoparticles into the N-doped bamboo-like carbon nanotube (NBCNT) with high catalytic performance and stability. The obtained NiFe@NBCNT hybrid exhibits a high electrochemical activity and stability with an unexpectedly low overpotential of ∼195 mV for OER at 10 mA cm-2 and an onset potential at 1...
July 13, 2018: ACS Applied Materials & Interfaces
Bingbing Cui, Bin Hu, Jiameng Liu, Minghua Wang, Yingpan Song, Kuan Tian, Zhihong Zhang, Linghao He
Exploiting high-efficiency and low-cost bifunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has been actively encouraged because of their potential applications in the field of clean energy. In this paper, we reported a novel electrocatalyst based on an exfoliated two-dimensional (2D) MXene (Ti3 C2 T x ) loaded with bimetallic oxide alloy nanoparticles (NPs) of Pt and Pd (represented by PtO a PdO b NPs@Ti3 C2 T x ), which was synthesized via solution plasma (SP) modification...
July 18, 2018: ACS Applied Materials & Interfaces
Yecan Pi, Qi Shao, Xing Zhu, Xiaoqing Huang
The anodic oxygen evolution reaction (OER) is central to various energy conversion devices, but the investigation of the dynamic evolution of catalysts in different OER conditions remains quite limited, which is unfavorable for the understanding of the actual structure-activity relationship and catalyst optimization. Herein, we constructed monodispersed IrNi x nanoparticles (NPs) with distinct composition-segregated features and captured their structural evolution in various OER environments. We decoded the interesting self-reconstruction of IrNi x NPs during the OER, in which an Ir-skin framework is generated in an acidic electrolyte, while a Ni-rich surface layer is observed in an alkaline electrolyte owing to Ni migration...
July 24, 2018: ACS Nano
Xiaohu Luo, Qiulan Zhou, Shuo Du, Ji Li, Jiawen Zhong, Xiulin Deng, Yali Liu
The exploration of highly efficient and stable bifunctional electrocatalysts for overall water splitting is currently of extreme interest for the efficient conversion of sustainable energy sources. Herein, we provide an earth-abundant, low-cost, and highly efficient bifunctional electrocatalyst composed of cobalt sulfide (Co9 S8 ) and molybdenum carbide (Mo2 C) nanoparticles anchored to metal-organic frameworks (MOFs)-derived nitrogen, sulfur-codoped graphitic carbon (Co9 S8 -NSC@Mo2 C). The new composite mode of the electrocatalyst was realized through simple pyrolysis processes...
July 5, 2018: ACS Applied Materials & Interfaces
Xiuju Wu, Yanli Niu, Bomin Feng, Yanan Yu, Xiaoqin Huang, Changyin Zhong, Weihua Hu, Chang Ming Li
Exploring sustainable and efficient electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is necessary for the development of fuel cells and metal-air batteries. Herein, we report a bimetal Fe/Mn-N-C material composed of spinel MnFe2 O4 /metallic Fe hybrid nanoparticles encapsulated in N-doped mesoporous hollow carbon nanospheres as an excellent bifunctional ORR/OER electrocatalyst in alkaline electrolyte. The Fe/Mn-N-C catalyst is synthesized via pyrolysis of bimetal ion-incorporated polydopamine nanospheres and shows impressive ORR electrocatalytic activity superior to Pt/C and good OER activity close to RuO2 catalyst in alkaline environment...
June 20, 2018: ACS Applied Materials & Interfaces
Haitao Wu, Wang Sun, Junrong Shen, David W Rooney, Zhenhua Wang, Kening Sun
The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are both fundamental and essential processes for various energy conversion and storage systems. The kinetics of ORR and OER play a critical role in their energy efficiency and practicality. Here, flower-like ultrathin Co3O4 nanosheets synthesized through a facile solvothermal technique were studied as a bifunctional catalyst for both water splitting and non-aqueous Li-O2 batteries. Due to the novel structure and highly active {110} and {100} exposed facets, which can effectively facilitate mass transfer and enhance catalytic capability, Co3O4 nanosheets exhibit better stability and higher ORR/OER activity than Co3O4 nanoparticles, Co3O4 bulks, Pt/C, and RuO2 in alkaline solution...
May 31, 2018: Nanoscale
Yang Liu, Feng Li, Haidong Yang, Jing Li, Ping Ma, Yan Zhu, Jiantai Ma
There is a vital need to explore highly efficient and stable non-precious-metal catalysts for the oxygen evolution reaction (OER) to reduce the overpotential and further improve the energy-conversion efficiency. Herein, we report a unique and cost-effective lyophilization and thermal treatment two-step procedure to synthesize a high-performance hybrid consisting of CoFe alloy nanoparticles embedded in N-doped carbon nanosheets interspersed with carbon nanotubes (CoFe-N-CN/CNTs) hybrid. The lyophilization step during the catalyst preparation leads to a uniform dispersion of carbon-like precursors and avoids the agglomeration of metal particles...
May 22, 2018: ChemSusChem
P Lettenmeier, J Majchel, L Wang, V A Saveleva, S Zafeiratos, E R Savinova, J-J Gallet, F Bournel, A S Gago, K A Friedrich
A stable and cost effective oxygen evolution reaction (OER) catalyst is crucial for the large-scale market penetration of proton exchange membrane (PEM) water electrolyzers. We show that the synthesis of iridium nanoparticles in either low purity ethanol or water, or in the absence of a surfactant, is detrimental to the electrocatalytic properties of the materials. Adding NaBH4 in excess improves the purity of the catalyst enhancing the OER activity up to 100 A gIr -1 at 1.51 V vs. RHE, the highest value reported so far for high purity Ir nanoparticles...
April 14, 2018: Chemical Science
Jinxiu Zhao, Xianghong Li, Guanwei Cui, Xuping Sun
Alkaline water splitting offers a simple method for the mass production of hydrogen but suffers from the sluggish kinetics of the anodic oxygen evolution reaction (OER). Here, we report on the development of an Fe-doped NiCr2O4 nanoparticle film on Ni foam (Fe-NiCr2O4/NF) as a non-noble-metal OER electrocatalyst with superior catalytic activity at alkaline pH. Such Fe-NiCr2O4/NF demands overpotentials as low as 228 and 318 mV to drive current densities of 20 and 500 mA cm-2, respectively, in 1.0 M KOH. Notably, it also shows strong long-term electrochemical durability with its activity being retained for at least 60 h...
May 24, 2018: Chemical Communications: Chem Comm
Wenming Zhang, Xiuyun Yao, Shengnan Zhou, Xiaowei Li, Ling Li, Ze Yu, Lin Gu
Herein, an approach is reported for fabrication of Co-Nx -embedded 1D porous carbon nanofibers (CNFs) with graphitic carbon-encased Co nanoparticles originated from metal-organic frameworks (MOFs), which is further explored as a bifunctional electrocatalyst for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Electrochemical results reveal that the electrocatalyst prepared by pyrolysis at 1000 °C (CoNC-CNF-1000) exhibits excellent catalytic activity toward ORR that favors the four-electron ORR process and outstanding long-term stability with 86% current retention after 40 000 s...
June 2018: Small
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