Heterogeneous electrocatalytic processes are notoriously difficult to simulate due to i) the complex structure of the catalyst and the electric double layer, ii) the applied bias potential that drives the reaction and iii) the variety of length and time scales on which relevant transformations happen. Accurate atomistic simulations must therefore be able to explore the configurational space of the catalyst surface – which requires fast electronic-structure methods – and enable the calculation of accurate free energies and reaction kinetics – which requires accurate electronic-structure methods. [more]