“…Other important catalytic activities are hydrogenation-dehydrogenation, oxidation, isomerization, aromatization, and DeNO x reactions. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] The basis for the activity of Cr in such a wide spectrum of reactions lies in the variability of oxidation states, of coordination envi-ronments, and of degree of polymerization of Cr oxide species. This variability is especially pronounced on the surface.…”