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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights Recent work on natural convection in electrochemistry is reviewed.  Experimental and theoretical/simulation studies in the area are considered.  Free convection driven by concentration and/or temperature gradients is discussed.  Natural convection in systems such as electrorefining and fuel cells is covered.  A critical assessment of the concept of 'spontaneous convection' is given.

Electrochemical experiments, especially those performed with scanning electrochemical microscopy (SECM), are often carried out without taking special care to thermostat the solution; it is usually assumed that its temperature is homogeneous and equal to the ambient. The present study aims to test this assumption via numerical simulations of the heat transfer in a particular system - the typical measurement cell for SECM. It is assumed that the temperature of the solution is initially homogeneous but different from that of its surroundings; convective heat transfer in the solution and the surrounding air is taken into account within the framework of the Boussinesq approximation. The hereby presented theoretical treatment indicates that an initial temperature difference of the order of 1 K dissipates with a characteristic time scale of ∼1000 s; the thermal equilibration is accompanied by convective flows with a maximum velocity of ∼10 m s; furthermore, the temporal evolution of the temperature profile is influenced by the sign of the initial difference. These results suggest that, unless the temperature of the solution is rigorously controlled, convection may significantly compromise the interpretation of data from SECM and other electrochemical techniques, which is usually done on the basis of diffusion-only models.

An optimised thermostated electrochemical cell is designed and implemented. This is informed by experimental and computational studies characterizing the extent to which the thermostating of an electrochemical cell via a heated bath can be realised, both with the cell closed and open to the environment. The heat transfer in the system is simulated and probed experimentally; special emphasis is put on heat loss due to radiation and evaporation. Experiments and simulations demonstrate that these two mechanisms of heat transfer lead to a steady temperature in the cell that differs from that of the thermostat by ∼0.1 K. Simulations indicate that spatial inhomogeneities in the stationary temperature drive natural convective flows with a significant velocity. These new physical insights inform the optimization of a new electrochemical cell and its application in measurements of the impact frequency of silver nanoparticles as a function of temperature.