Some of the Reviewer`s Comments about our research
Induced Anomalous Enhancement in the Work Function of
Nanostructures
Jasmin Kaur and Rama Kant, J. Phys. Chem. Lett., 2015, ASAP
Reviewer:
1
In the manuscript
"Curvature Induced Anomalous Enhancement in the Work Function of
Nanostructures" by J. Kaur and R. Kant the authors present very
interesting results on the influence of curvature on the work function of
nanostructures. They show that nanomaterials exhibit
very different work function values when compared with the bulk ones due to
their different geometry which significantly affects the electronic properties
of nanomaterials such as metals and semi-metals.
Taking into account that the work function affects significantly several
surface/interfacial properties of materials (and devices) I think that this
work will have significant impact in the scientific community. Furthermore, the
paper is well-presented and fits the scope of the journal. I therefore suggest
acceptance with only one minor suggestion: it would benefit the readership if
the authors include specific examples of work function changes in different
materials.
Additional Questions:
Urgency: High
Significance: High
Novelty: High
Scholarly Presentation: Top 10%
Is the paper likely to interest a substantial number of physical chemists, not
just specialists working in the authors' area of research?: Yes
Theory of Generalized Gerischer Admittance of Realistic Fractal
Electrode
R. Kumar and R. Kant, J. Phys. Chem. C, 2009,
113, 19558.
Reviewer: 3
``This is good work, its authors should
be congratulated, and it certainly deserves publication. The authors have done
the hard work of solving a difficult problem- but they must still communicate
it efficiently to their intended audience. ....``
``…The authors address an important
aspect of a problem that has bedeviled modern electrochemistry, as it has moved
in recent decades from the smooth, chemically homogeneous mercury / solution
interface to the much more prevalent solid metal / solution interface….``
``…I regret that my critical comments
take so much space (because they must be specific to have a possible impact)
than my laudatory introduction, but they should not overshadow my regard for
what the authors are trying to share. Their science is good - I
hope they will keep up their good work, and also learn to communicate it
efficiently.``
Reviewer: 2
``The paper is an
important continuation of the series of the authors dealing with the kinetics
of fractal electrodes. Aptly, the authors accentuate in the Conclusion that, in
contradistinction to a number of earlier works on the same subject which make
use of dimension analysis only, their method rests on a straightforward
analytical treatment of the problem, based on Fick’s
Law and linearized Nernst equation. This approach,
beyond its depth of understanding, enables the authors to consider the effect
not only of fractal dimension but also of further geometrical properties.
Whereas in some of their previous publications they dealt with diffusion
limited reactions (i.e. diffusion and electrode reaction are consecutive
processes) the present work discusses diffusion controlled reactions,
where diffusion and chemical reaction proceed in parallel. In other words the
problem of Gerischer impedance is generalized for (certain types of) fractal
surfaces. ``
``I think the approach is most demanding and
the results are convincing; the final expression, eq. (18), is clear and even
artistic. Whereas I have to admit that I did not follow the mathematics
line by line I felt the rigor of the work to be impressive. An important boon
of the MS is that it offers clear methods to support or falsify the statements
made, by giving a number of graphs in the Discussion, which can be investigated
experimentally.``
Theory of Anomalous Diffusion
Impedance of Realistic Fractal Electrode
R. Kant, R. Kumar and V. K. Yadav, J.
Ρhys. Chem. C (Letter) 2008, 112,
4019.
Reviewer: 2
``The manuscript contains a high quality
work which certainly deserves publication, after modifications. The subject is
the diffusion controlled flux towards an interface. This is a time-dependent
quantity which depends on the interface conditions. One form of the flux-time
relation, widely used in electrochemistry context, is the Warburg impedance.
The original form (of 1898) refers to a planar electrode with semiinfinite diffusion geometry – yielding Eq.1. If the
electrode is not planar but of different geometry, then different frequency
dependence is obtained. One important –many decades old- question is: what is
the frequency dependence of the diffusional impedance if the surface is rough?
For this question, perhaps the best general answer up till now was given by
one of the authors (Ref.6) a few years ago by deriving a set of equations
similar to Eq.6. In the meantime a formalism for characterizing realistic”
self-affine surfaces have also appeared (Refs.34 and 38, Eq.5) The authors
combine Eqs. 5 and 6, to obtain the impedance of the
„realistic” self-affine surfaces (this is the complicated equations of Eqs 7 to 10). These are indeed complicated functions, their
frequency dependence can be illustrated numerically only. This is done in
Section 3. The last sentence of the conclusions – ``Finally one can say, this
theory is an indispensable step in the quantitative description of the role of
roughness on the Warburg impedance.``- is absolutely true.``
Theory of anomalous diffusive
reaction rates on realistic self-affine fractals
R. Kant and S. K. Jha J. Ρhys. Chem. C (Letter) 2007, 111,
14040.
Reviewer: 1
``The subject of the manuscript is a classical
problem of physical chemistry, i.e. the time-dependence of diffusional flux
to a surface following a step of surface reactivity (like a potential step in
electrochemistry). Such theories are well-known and their results are often
employed e.g. by electrochemists for analyzing current transients; for cases of
non-trivial geometries of the irregular, e.g. rough surfaces the problem is
still not completely solved. One solution might be the approximation of the
surface by a self-similar fractal leading to a power-law flux-time equation. Dr
Kant presents a much more precise analysis: in his present model the
surface is modelled by a self-affine fractal
(characterized by four parameters); the current-time function is calculated
(Eq.7); its special cases for long and short times are given and discussed.``
Reviewer:
``The letter is
addressed to a long-standing problem of diffusive transport across irregular
interfaces appearing in different areas of modern science. The classical power law approximation of the total
flux (or current) as a function of time is replaced by an improved equation
that takes into account not only the fractal dimension of the surface but also
its minimal cutoff and topothesy. The theoretical predictions are confronted to
experimental measurements (published by other authors elsewhere) with
success.---``
General Theory of Arbitrary
Potential Sweep Methods on an Arbitrary Topography Electrode and Its
Application to Random Surface Roughness
R. Kant, J. Ρhys. Chem. C 2010, 114, 10894.
Reviewer: 1
``The manuscript provides a general theory for
determining the current at an electrode interface that does not have a
simplified, smooth surface geometry. The mathematical equations take into
account changes in three vector directions and with respect to time. The
arguments and derivations are elegant. The implications of the work are
significant to the techniques of cyclic voltammetry and linear sweep voltammetry.---``
Reviewer: 2
``This is an excellent work form the applied
mathematical point of view.----``
Theory of Generalized Cottrellian
Current at Rough Electrode with Solution Resistance Effects
S. Srivastav
and R. Kant, J. Ρhys. Chem. C 2010, 114, 10066.
Reviewer: 1
``This is an important and well written paper
describing the effect of surface roughness on potential step transients in the
presence of significant ohmic resistance. The areas
of electrode roughness and of the effects of solution resistance are currently
of active interest worldwide so this is a timely paper which will draw the
interest of many readers as it adds to the body of scholarly work in these
difficult areas. Moreover there exist few works on the combination of both
effects.``
Theory of Absorbance Transients of an Optically
Transparent Rough Electrode
Rama Kant and Md. Merajul Islam, J. Ρhys. Chem. C 2010, 114, 19357-19364.
Reviewer: 1
``A novel theory for absorbance transients of an
optically transparent electrode was well developed in this paper. The paper is
well established not only logically but also linguistically.---``
Reviewer: 2
``The manuscript
proposes a theory to predict the absorbance changes in time in optical
transparent electrodes (OTE) of varying surface roughness during spectroelectrochemical methods. The topic is timely and of
importance, provides a better understanding of the surface processes on OTE.---``
Anomalous Warburg
Impedance: Influence of Uncompensated Solution Resistance
S. Srivastav
and R. Kant, J. Ρhys. Chem. C 2011, accepted for publication.
Reviewer: 1
``To face the problem of anomalous Warburg impedance,
this paper presents theoretical results incorporating the diffusion at the
rough electrode/electrolyte interface and bulk solution resistance by means of
two phenomenological scales. The problem is important because it is difficult
to establish an analytical relation connecting geometrical characteristics of
the roughness and the resulting impedance. In this paper, the authors present a
successful perturbation analysis by means of which explicit relationships are
elucidated. In particular, the roles of fractal dimension, surface roughness
amplitude, and some significant characteristic lengths are discussed in terms
of analytical results. In this sense, the paper represents a good and welcome
contribution to the literature dedicated to the electrical response of
electrolytic cells and interface problems arising in this context.-----Anyway,
the paper represents a good contribution to the field and should be considered
seriously for publication in JPC.``
Theory
of Quasi-Reversible Charge Transfer Admittance on Finite Self-Affine Fractal
Electrode
R. Kumar and R. Kant, Electrochimica Acta, 2011, accepted for publication
Reviewer: 1
``The manuscript analyses the coupling
of the charge transfer resistance with the Warburg impedance for the case of a
rough electrode. The electrode geometry is modelled
by a self-affine fractal.
Rama Kant's activity on this and related
fields started almost two decades ago, with the (highly esteemed) late
Professor Rangarajan. This is, per se, a guarantee of high quality. Since that
time he and coworkers/students have analyzed the kinetics of a number of
diffusion-related electrode reaction scenarios for irregular, rough electrode
geometries. These are impressive calculations leading to very complicated
equations. As a reviewer with insufficient mathematical skills and having short
time for the understanding all details of the calculation, I can only trust
(but I do trust) the correctness of the present calculations. The starting
equations are correct, the results (Bode diagrams of Fig.3) are reasonable, the
way of presentation is elegant, so all what I can write: congratulations to the
authors, and suggest the Editor to publish it, as it is, or with some
modifications.----``
Reviewer: 2
``This manuscript addresses the
influence of electrode surface roughness on the Randles
impedance. The mathematical description is very complex and I am in no position
to comment on this. Nevertheless, the results look very reliable. The
manuscript has been written in a reasonably concise manner, explaining the
different steps taken in the derivations in a clear manner (for someone who is
well-versed in this matter).----``
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