Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electroconvective instability in water electrolysis: an evaluation of
  electroconvective patterns and their onset features   In electrochemical systems, an understanding of the underlying transport
processes is required to aid in their better design. This includes knowledge of
possible near-electrode convective mixing that can enhance measured currents.
Here, for a binary acidic electrolyte in contact with a platinum electrode, we
provide evidence of electroconvective instability during electrocatalytic
proton reduction. The current-voltage characteristics indicate that
electroconvection, visualized with a fluorescent dye, drives current densities
larger than the diffusion transport limit. The onset and transition times of
the instability do not follow the expected inverse-square dependence on the
current density, but, above a bulk-reaction-limited current density are delayed
by the water dissociation reaction. The dominant size of the electroconvective
patterns is also measured and found to vary as the diffusion length scale,
confirming previous predictions on the size of electroconvective vortices.

1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
4
The categories of this paper are: cond-mat
33
The categories of this paper are: plasm-ph
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas