The depletion of fossil fuels and increasing environmental concerns demand efficient, pollution-free energy technologies. The key point is to develop highly efficient electrocatalytic devices, for example fuel cells, which directly convert chemical energy to direct-current electrical energy, without burning dirty fuels, such as oil or gasoline. However, practical energy and power densities and the cost of catalytic components of the electrochemical systems, i.e. platinum for fuel cell applications, limit their competitiveness relative to conventional technologies. The thermodynamics and kinetics of these electrochemical reactions are driven by the size, the geometrical structure and the chemical composition of the electrode material. Our growing ability to manipulate matter at a nanoscale regime, with complete control of the chemical composition, provides a new and unique opportunity to design materials with the desired catalytic properties. This project will discuss, using a computational approach, how the electronic, surface and crystal structures can be tailored to design and characterise better nanoalloy electrocatalysts for fuel cell applications.