A transition metal oxofluoride offering advantages in electrocatalysis and potential use in applications

2016 ◽  
Vol 188 ◽  
pp. 481-498 ◽  
Author(s):  
H. Svengren ◽  
N. Torapava ◽  
I. Athanassiadis ◽  
S. I. Ali ◽  
M. Johnsson

The recently described solid solution (Co,Ni,Mn)3Sb4O6F6has proved stable and efficient as a catalyst for electrocatalytic water oxidation. The end component Co3Sb4O6F6was found to be most efficient, maintaining a current density ofj= 10 mA cm−2at an overpotential of 443 mV with good capability. At this current density, O2and H2were produced in the ratio 1 : 2 without loss of faradaic current against a Pt-cathode. A morphological change in the crystallite surface was observed after 0.5 h, however, even after 64.5 h, the overall shape and size of the small crystallites were unaffected and the electrolyte contained only 0.02 at% Co. It was also possible to conclude fromin situEXAFS measurements that the coordination around Co did not change. The oxofluorides express both hydrophilic and hydrophobic surface sites, incorporate a flexible metalloid element and offer the possibility of a mechanism that differs from other inorganic catalytic pathways previously described.

2018 ◽  
Vol 54 (18) ◽  
pp. 2300-2303 ◽  
Author(s):  
Maowen Xie ◽  
Xiaoli Xiong ◽  
Lin Yang ◽  
Xifeng Shi ◽  
Abdullah M. Asiri ◽  
...  

An Fe-(tetracyanoquinodimethane)2 nanowire array in situ developed on Fe foil (Fe(TCNQ)2/Fe) acts as an efficient and durable electrocatalyst for water oxidation, needing an overpotential of 340 mV to attain a current density of 10 mA cm−2 in 1.0 M KOH.


2018 ◽  
Vol 54 (51) ◽  
pp. 7046-7049 ◽  
Author(s):  
Jiale Xing ◽  
Kailu Guo ◽  
Zehua Zou ◽  
Minmin Cai ◽  
Jing Du ◽  
...  

Uniform and well-ordered NiFe-MOF-74 was in situ grown on Ni foam by Fe2+ induction, exhibiting enhanced activity toward the OER with a very low overpotential of 223 mV at a current density of 10 mA cm−2.


2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Zhanwu Lei ◽  
Wenbin Cai ◽  
Yifei Rao ◽  
Kuan Wang ◽  
Yuyuan Jiang ◽  
...  

AbstractSingle-atom catalysts (SACs) have attracted tremendous research interests in various energy-related fields because of their high activity, selectivity and 100% atom utilization. However, it is still a challenge to enhance the intrinsic and specific activity of SACs. Herein, we present an approach to fabricate a high surface distribution density of iridium (Ir) SAC on nickel-iron sulfide nanosheet arrays substrate (Ir1/NFS), which delivers a high water oxidation activity. The Ir1/NFS catalyst offers a low overpotential of ~170 mV at a current density of 10 mA cm−2 and a high turnover frequency of 9.85 s−1 at an overpotential of 300 mV in 1.0 M KOH solution. At the same time, the Ir1/NFS catalyst exhibits a high stability performance, reaching a lifespan up to 350 hours at a current density of 100 mA cm−2. First-principles calculations reveal that the electronic structures of Ir atoms are significantly regulated by the sulfide substrate, endowing an energetically favorable reaction pathway. This work represents a promising strategy to fabricate high surface distribution density single-atom catalysts with high activity and durability for electrochemical water splitting.


1985 ◽  
Vol 53 ◽  
Author(s):  
F. Namavar ◽  
J. I. Budnick ◽  
F. H. Sanchez ◽  
H. C. Hayden

ABSTRACTWe have carried out a study to understand the mechanisms involved in the formation of buried SIO2 by high dose implantation of oxygen into Si targets. Oxygen ions were implanted at 150 keV with doses up to 2.5 X 1018 ions/cm2 and a current density of less than 10 μA/cm2 into Si 〈100〉 at room and liquid nitrogen temperatures. In-situ Rutherford backscattering (RBS) analysis clearly indicates the formation of uniform buried SIO2 for both room and liquid nitrogen temperatures for doses above 1.5 X 1018/cm2.Oxygen ions were implanted at room temperature into crystalline quartz to doses of about 1018 ions cm2 at 150 keV, with a current density of 〈10〉10 μA/cm2. The RBS spectra of the oxygen implanted quartz cannot be distinguished from those of unimplanted ones. Furthermore, Si ions were implanted into crystalline quartz at 80 keV and dose of 1 X 1017 Si/cm2, and a current aensity of about 1 μA/cm2. However, no signal from Si in excess of the SiO2 ratio could be observed. Our results obtained by RBS show that implantation of either Si+ or O into SiO2 under conditions stated above does not create a layer whose Si:O ratio differs measurably from that of SiO2.


CrystEngComm ◽  
2018 ◽  
Vol 20 (45) ◽  
pp. 7329-7336 ◽  
Author(s):  
Xingang Kong ◽  
Xing Wang ◽  
Dingying Ma ◽  
Jianfeng Huang ◽  
Jiayin Li ◽  
...  

Porous network Zn2Ti3O8 platelike nanoarchitecture was prepared by an ion exchange reaction and further in situ topotactic transformation, and it exhibited an enhanced reversibility capacity of 408 mA h g−1 after 1000 cycles at a current density of 1 Ag−1.


2004 ◽  
Vol 36 (2) ◽  
pp. 105-112 ◽  
Author(s):  
M. Spasojevic ◽  
Aleksa Maricic ◽  
Lidija Rafailovic

Cobalt and nickel alloy powders were obtained by electrochemical deposition on a titanium cathode from an ammonium solution of cobalt and nickel sulfate. Powders of a specific chemical structure and composition, particle shape and size were obtained by an appropriate choice of electrolysis parameters, current density, deposit growth rate and solution temperature and composition. Within the current density range of 5 - 450 mAcm-2, the current density did not significantly affect the chemical composition of the powders, but had a significant effect on the particle structure, shape and size. Crystal particles formed at a current density lower than 30 mAcm-2. Amorphous powders were obtained at a current density higher than 50 mAcm-2. Structural changes of the obtained amorphous powder of 55mol.% Ni, 45 mol.% Co, pressed under the pressure of 100 MPa, were investigated by measuring the temperature dependence of electrical resistance in isothermal and non-isothermal conditions varying from room temperature to 750?C. The process of thermal stabilization of defects that appeared during pressing occurred within the temperature range of 200-390?C. The DSC method was used to determine that the powder crystallization process occurred in two stages with peak temperatures of the exothermal maximum in the first and second stage of T1 = 438?C and T2 = 573?C, respectively. A distinct correlation between the change of electrical resistance and the crystallization process was established. The reduction of electrical resistively occurs during each crystallization stage.


2019 ◽  
Vol 55 (11) ◽  
pp. 1564-1567 ◽  
Author(s):  
Husileng Lee ◽  
Xiujuan Wu ◽  
Qilun Ye ◽  
Xingqiang Wu ◽  
Xiaoxiao Wang ◽  
...  

A hierarchical 3D CoS2/Ni3S2/CoNiOx water oxidation catalyst can maintain a current density of 1 A cm−2 for one week in 30% KOH solution with a slight increase of the overpotential.


RSC Advances ◽  
2018 ◽  
Vol 8 (40) ◽  
pp. 22799-22805 ◽  
Author(s):  
Songhu Bi ◽  
Jingde Li ◽  
Qin Zhong ◽  
Chuntan Chen ◽  
Qiyi Zhang ◽  
...  

A low-cost CoFe2O4/biomass carbon (CFO@BC/Zn) hybrid from Co-enriched Sulfate Reducing Bacteria (Co-SRB) as an electrocatalyst for OER. The electrocatalyst exhibits a low potential of 1.53 V at a current density 10 mA cm−2 and Tafel slope of 86 mV dec−1.


2011 ◽  
Vol 04 (01) ◽  
pp. 31-36 ◽  
Author(s):  
QING LU ◽  
YIKAI ZHOU

Herein, a modified interfacial synthetic route has been demonstrated by synthesizing uniform poly(3,4-ethylenedioxythiophene)/ MnO 2 hierarchical mesoporous nanocomposite. The in-situ generated polymer has been proven to be effective in constraining the overgrowth of nuclei. Consequently, assembled nanosheets with a thickness less than 5 nm have been prepared. At a high rate of 10 A g-1 charge/discharge process, the nanocomposite electrode retains 73.4% of the specific capacitance exhibited at 1 A g-1. At a current density as large as 800 mA g-1, the nanocomposite electrode attains reversible lithium storage specific capacities of 400 mAh g-1 after 50 cycles and 300 mAh g-1 after 100 cycles. The excellent high-rate performance of the nanocomposite electrode is highlighted in terms of its extremely large surface area, unique microstructure and mesoporous features.


2018 ◽  
Vol 5 (8) ◽  
pp. 1795-1799 ◽  
Author(s):  
Jiahao Yu ◽  
Fulin Yang ◽  
Gongzhen Cheng ◽  
Wei Luo

A facile and cost-effective one-step hydrothermal method is used to synthesize NiFe LDH microclusters with a 3D hierarchically mesoporous architecture. This superior electrocatalyst can achieve a current density of 10 mA cm−2 with an ultralow overpotential of 211 mV toward the oxygen evolution reaction.


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