Materials comprising carbon-embedded nickel nanoparticles, processes for their manufacture, and use as heterogeneous catalysts

A catalytically active material, comprising grains of non-graphitizing carbon with nickel nanoparticles dispersed therein, wherein said nickel is in the form of elemental nickel, nickel combined with one or more dopant metals and/or nickel combined with one or more secondary metals, wherein:

• dp, the average diameter of nickel nanoparticles in the non-graphitizing carbon grains, is in the range of 1 nm to 20 nm;
• D, the average distance between nickel nanoparticles in the non-graphitizing carbon grains, is in the range of 2 nm to 150 nm;
• and
• ω, the combined total mass fraction of said nickel, said dopant metals and said secondary metals in the non-graphitizing carbon grains, is in the range of 30 wt % to 70 wt % of the total mass of the non-graphitizing carbon grains;
• wherein dp and D are measured by TGZ-TEM, and dp, D and ω conform to the following relation:
• 4.5 dp/ω>D≥0.25 dp/ω.