  Thermo-osmotic flows - flows generated in micro and nanofluidic systems by
thermal gradients - could provide an alternative approach to harvest waste
heat. However, such use would require massive thermo-osmotic flows, which are
up to now only predicted for special and expensive materials. There is thus an
urgent need to design affordable nanofluidic systems displaying large
thermo-osmotic coefficients. In this paper we propose a general model for
thermo-osmosis of aqueous electrolytes in charged nanofluidic channels, taking
into account hydrodynamic slip, together with the different solvent and solute
contributions to the thermo-osmotic response. We apply this model to a wide
range of systems, by studying the effect of wetting, salt type and
concentration, and surface charge. We show that intense thermo-osmotic flows
can be generated using slipping charged surfaces. We also predict for
intermediate wettings a transition from a thermophobic to a thermophilic
behavior depending on the surface charge and salt concentration. Overall, this
theoretical framework opens an avenue for controlling and manipulating
thermally induced flows with common charged surfaces and a pinch of salt.
