  Catalytic Janus swimmers demonstrate a diffusio-phoretic motion by
self-generating the gradients of concentrations and electric potential. Recent
work has focused on simplified cases, such as a release of solely one type of
ions or low surface fluxes of ions, with limited theoretical guidance. Here, we
consider the experimentally relevant case of particles that release both types
of ions, and obtain a simple expression for a particle velocity in the limit of
thin electrostatic diffuse layer. Our approximate expression is very accurate
even when ion fluxes and surface potentials are large, and allows one to
interpret a number of intriguing phenomena, such as the reverse in the
direction of the particle motion in response to variations of the salt
concentration or self-diffusiophoresis of uncharged particles.
