TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Device: The fuel cell is a photovoltaic cell, where the anode is at least in part made of an n-type semiconductor. The photocathode comprises PdXe.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The palladium layer is essentially continuous. It comprises a layer of a metal deposited on a substrate by an electrochemical or electroless method. It comprises palladium black deposited on a substrate. Palladium black is deposited on a carbon, polymer, semiconductor or metallic substrate. The palladium layer comprises deposited micro- and/or nanoparticles of palladium. The micro- and/or nanoparticles of palladium are at least partially aggregated. The deposited micro- and/or nanoparticles of palladium are deposited from a colloid/suspension on a carbon, polymer or metallic substrate. The catalyst layer is located between the electrolyte and the cathode. It comprises the cathode, where cathode comprises palladium-xenon (PdXe). Preferably, the inert gas is N, Ar or Xe. The metal is a transition metal, preferably a metal from the platinum group metals. Preferred Parameters: The thickness of the palladium layer is from 0.75 nm to 1 mu m. A value of the lattice constant for the metallic palladium layer implanted with inert gas ions determined by the X-ray diffraction method is higher than the lattice constant of pure palladium. The mean atomic ratio palladium (Pd):X in the near-surface layer of the thickness of 50 nm is from 10000:1 to 1:1. The value of the lattice constant is higher than the lattice constant of pure palladium by at least 0.008 Angstrom , preferably by 0.038 Angstrom , more preferably by 0.065 Angstrom , even more preferably by 0.1 Angstrom . Value of the lattice constant is 3.92-4.10 Angstrom , preferably 3.98-4.05 Angstrom . A thickness of the palladium layer containing the implanted inert gas is 0.2-1000 nm, preferably 0.2-100 nm. Distribution of inert gas atoms versus the depth is essentially Gaussian.