Sonochemical intercalation synthesis of nano γ-nickel oxyhydroxide: Structure and electrochemical properties

Liu, Lipu; Zheng-tao, Zhou; Peng, Chenghong

doi:10.1016/j.electacta.2008.07.055

Cited by 45 publications

(20 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Besides, NiNT solid does not show the Na 2 Ti 3 O 7 tubular structure probably in reason of the fact that part of the Ni 2+ species might be intercalated into the NTs structure, but most of these species are found in the NiOOH form on the NTs surface. This could be a result of ammonia washing during the synthesis of the solids, in agreement with the findings [ 29 , 30 ]. Moreover, the good dispersion of intercalated Pt nanoparticles (decorated) on the nanotubes shows that the impregnation of Pt on NTs does not significantly affect the titanate structure, implying that the scrolled titanate nanosheets remain.…”

Section: Resultssupporting

confidence: 92%

Effects of the Incorporation of Distinct Cations in Titanate Nanotubes on the Catalytic Activity in NOx Conversion

et al. 2021

View full text Add to dashboard Cite

Effects of the incorporation of Cr, Ni, Co, Ag, Al, Ni and Pt cations in titanate nanotubes (NTs) were examined on the NOx conversion. The structural and morphological characterizations evidenced that the ion-exchange reaction of Cr, Co, Ni and Al ions with the NTs produced catalysts with metals included in the interlayer regions of the trititanate NTs whereas an assembly of Ag and Pt nanoparticles were either on the nanotubes surface or inner diameters through an impregnation process. Understanding the role of the different metal cations intercalated or supported on the nanotubes, the optimal selective catalytic reduction of NOx by CO reaction (SCR) conditions was investigated by carrying out variations in the reaction temperature, SO2 and H2O poisoning and long-term stability runs. Pt nanoparticles on the NTs exhibited superior activity compared to the Cr, Co and Al intercalated in the nanotubes and even to the Ag and Ni counterparts. Resistance against SO2 poisoning was low on NiNT due to the trititanate phase transformation into TiO2 and also to sulfur deposits on Ni sites. However, the interaction between Pt2+ from PtOx and Ti4+ in the NTs favored the adsorption of both NOx and CO enhancing the catalytic performance.

show abstract

Section: Resultssupporting

confidence: 92%

Effects of the Incorporation of Distinct Cations in Titanate Nanotubes on the Catalytic Activity in NOx Conversion

et al. 2021

View full text Add to dashboard Cite

show abstract

“…To reveal the in situ information of Ni hydroxides during OER, we successfully synthesized the phase-controllable a-Ni(OH) 2 , b-Ni(OH) 2 using asimple method [11] and g-NiOOH through precipitation-oxidation approach. [12] TheX -ray diffraction (XRD) patterns (Figure S5a,b) support the formation of pure hexagonal a-Ni-(OH) 2 (JCPDS #38-0715) and hexagonal b-Ni(OH) 2 (JCPDS #14-0117) phases,w hile the g-NiOOH does not exhibit ar egular crystalline phase (Figure S10a) as reported previously. [13] Theexperimental setup and the working principle of on-chip CV and in situ electrical transport spectroscopy (ETS) [3a,9] of g-NiOOH and a-Ni(OH) 2 are illustrated in Figure 2a and Figures S12-S19.…”

Section: Resultssupporting

confidence: 80%

“…To detect the near-equilibrium results before and during OER, [14] the scan rate in this work was kept slow (2 mV s À1 )t oe liminate variations.T ypical results for g-NiOOH and a-Ni(OH) 2 are shown in Figure 2c,d. Tw oredox peaks were observed in the CV curves prior to OER, which we ascribe to the Ni II -Ni III and Ni III -Ni III/IV redox processes according to reported results, [12] respectively.T he CV of empty Au electrode effectively exclude the interference of Au (Figure S19). Along with the CV cycles,the initial conductivity of g-NiOOH and a-Ni(OH) 2 are both low before Ni II -Ni III oxidation.…”

Section: Resultssupporting

confidence: 74%

Double‐Exchange‐Induced in situ Conductivity in Nickel‐Based Oxyhydroxides: An Effective Descriptor for Electrocatalytic Oxygen Evolution

et al. 2021

View full text Add to dashboard Cite

The electrocatalytic oxygen evolution reaction (OER) plays an important role in sustainable energy conversion from water to hydrogen fuel. The most effective non-noble metal catalyst for OER is currently Fe-doped NiOOH (Ni1-xFexOOH), but its overpotential (theoretically calculated η = 0.4) is too large for practical applications. Motivated by our in silico predictions that Ir dopant would lead to a very low overpotential to improve OER activity of Ni-based hydroxides, we report here an experimental confirmation on the altered OER activities for a series of metals (Mo, W, Fe, Ru, Co, Rh, Ir) doped into γ-NiOOH. Most interestingly, we observed that the in situ (intermediate) electrical conductivity for metal doped γ-NiOOH correlates well with the trend in enhanced OER activities. This correlation allows experimental screening of new candidates with fast measurements of intermediate conductivity, while also providing additional information about the catalytic mechanism. To understand the basis of this correlation, we used density functional theory (DFT) calculations to explain the in situ conductivity of the key intermediate states of metal doped γ-NiOOH during OER. The simultaneous increase of OER activity with in situ conductivity was rationalized by their intrinsic connections to the radical character promotion in the metal-oxo bond. This electrical transport characteristic, which was later linked to the double exchange (DE) interactions between adjacent metal ions with various d orbital occupancies, serves as an effective indicator for the key metal-oxo radical character, providing a facile and effective descriptor for the theoretical and experimental guidance in design and screening of efficient OER catalysts.

show abstract

“…As both A1 and C1 have shifted to higher potentials, it is unlikely that this shift is due to the transition of the oxide layer towards the β/β structure as the cathodic peak corresponding to the reduction of β-NiOOH to β-Ni(OH) 2 is normally at a more cathodic potential than the γ-NiOOH to α-Ni(OH) 2 reaction [8,10,16]. One could suggest that these two peaks equivalent to those labelled as A3 and C3 in Figure 3b, but this is also unlikely as A3 and C3 are usually observed along with A1 and C1 [8,22]. One may also argue that this shift is caused by a shift in the potential of the reference electrode, however this is unlikely due to the regular testing of reference electrodes against stable standards in our laboratory.…”

Section: Periodic or Continuous Rejuvenationmentioning

confidence: 98%

“…For example, raman spectroscopy suggests that at the onset of oxygen evolution, NiOOH transforms to another phase [15] and similarly our cyclic voltammetry work suggested that after extensive oxygen evolution (at least 40 hours at 50 mA cm -2 ) an additional phase forms [8]. Many authors have also suggested that over-oxidation causes Ni(IV) to form [6,[20][21][22][23], although there is currently little direct evidence of the formation of NiO 2 or other Ni(IV) species.…”

Section: Introductionmentioning

confidence: 94%

Electrocatalytic oxygen evolution on nickel oxy-hydroxide anodes: Improvement through rejuvenation

Mellsop

Gardiner

Marshall

2015

Electrochimica Acta

View full text Add to dashboard Cite

The ageing and rejuvenation behaviour of nickel oxy-hydroxide anodes for alkaline water electrolysis is investigated. The anodically formed oxy-hydroxide material is known to age over time causing a decrease in performance. However, this deactivation can be mitigated by temporarily reducing the potential for brief periods. This work looks at continuous rejuvenation of nickel anodes in 30wt.% KOH solution and it is shown that rejuvenation at 0.5 V vs. HgHgO for 10 minutes every 100 minutes can prevent ageing of the anode, thus maintaining a low overpotential during galvanostatic oxygen evolution at 50 mA cm -2 . It is suggested that the short potentiostatic rejuvenation periods at regular intervals prevents the ratio of Ni(IV) to Ni(III) from increasing, thereby maintaining the intrinsic activity of the material. The rejuvenation potential must be above 0.36 V vs. HgHgO to ensure it is effective in obtaining good performance (i.e. the material must not reduce to Ni(II)). These findings suggest that electrolysis systems using nickel anodes could benefit from direct coupling to fluctuating power sources such as solar or wind, where the variability in their power output could facilitate the rejuvenation of the nickel anode. We estimate that by using the rejuvenation steps, an energy saving of 9% is possible in an alkaline water electrolyser using nickel anodes.

show abstract

Sonochemical intercalation synthesis of nano γ-nickel oxyhydroxide: Structure and electrochemical properties

Cited by 45 publications

References 31 publications

Effects of the Incorporation of Distinct Cations in Titanate Nanotubes on the Catalytic Activity in NOx Conversion

Effects of the Incorporation of Distinct Cations in Titanate Nanotubes on the Catalytic Activity in NOx Conversion

Double‐Exchange‐Induced in situ Conductivity in Nickel‐Based Oxyhydroxides: An Effective Descriptor for Electrocatalytic Oxygen Evolution

Electrocatalytic oxygen evolution on nickel oxy-hydroxide anodes: Improvement through rejuvenation

Contact Info

Product

Resources

About