“…The treatment of zinc oxide with oxygen and argon plasmas was found in [10] to increase the surface acidity of ZnO, determined from the adsorption of pyridine from octane. Figure 3 shows the dependence of the yield of acetone (at T = 593 K) on the number of adsorbed pyridine molecules, i.e., the number of acid sites per 1 cm 2 of ZnO surface.…”