NOVELTY - Use of mesoporous graphite particles with a loading of sintering-stable metal-nanoparticles (M-HGS) (hollow graphitic spheres) as a catalyst in electrochemical applications, is claimed. The particles have a hollow spherical structure with a mesoporous graphite shell of 20-50 nm thickness and a hollow core having 60-440 nm diameter. The loading of the graphite shell includes: a catalytically active metal including platinum, rhodium, palladium, ruthenium, and/or precious metal-based alloys; and 5-50 wt.%, preferably 10-40 wt.% cobalt, nickel, iron, tungsten, vanadium, copper, and/or zinc.    USE - The mesoporous graphite particles are useful as an oxidation catalyst (anode) or as a reduction catalyst (cathode) in fuel cells, or as a layer component in a layer structure of a membrane-electrode-unit of a fuel cell, electrochemical cells e.g. electrolysis cells, and electrochemical reformers or batteries (all claimed).    ADVANTAGE - The graphite particles: have large specific surface area ensuring increased capacity for accepting reactants, improved stability provided by the small pores within the coating layer, good electrical conductivity, good thermal conductivity for transporting exhaust heat, and excellent corrosion resistance; enables an efficient water- and oxygen transport, and other liquid substances e.g. water, water vapor, ammonia, methanol into and through the particles due to their porosity; allows a good wettability with the electrolyte on the surface structure in the catalyst layer of an electrode, which enables good accessibility of the catalytically active metal; and achieves improved mechanical stability and good processability during compression of the membrane-electrode-unit including anode, membrane and cathode, or under mechanical stress.    DETAILED DESCRIPTION - Use of mesoporous graphite particles having a loading of sintering-stable metal-nanoparticles (M-HGS) (hollow graphitic spheres) as a catalyst in electrochemical applications, is claimed. The particles have a hollow spherical structure with a mesoporous graphite shell of 20-50 nm thickness and a hollow core having a diameter of 60-440 nm. The loading of the graphite shell includes: a catalytically active metal including platinum, rhodium, palladium, ruthenium, and/or precious metal-based alloys; and 5-50 wt.%, preferably 10-40 wt.% cobalt, nickel, iron, tungsten, vanadium, copper, and/or zinc, based on the total weight of the metal-loaded particles. An INDEPENDENT CLAIM is also included for a use of mesoporous graphite particles without the loading of sintering-stable metal-nanoparticles (n-HGS) in electrochemical applications, optionally in combination with the mesoporous graphite particles with the loading of sintering-stable metal-nanoparticles (M-HGS) as the catalyst in the electrochemical applications, where the particles have a hollow spherical structure with a mesoporous graphite shell of 20-50 nm thickness and a hollow core having a diameter of 60-440 nm. The loading of the graphite shell includes: a catalytically active metal including platinum, rhodium, palladium, ruthenium, and/or precious metal-based alloys; and 5-50 wt.%, preferably 10-40 wt.% cobalt, nickel, iron, tungsten, vanadium, copper, and/or zinc, based on the total weight of the metal-loaded particles.