Catalytic activity and capacitance of tungsten carbide as a function of its dispersity and surface state

Abstract

The catalytic activity and total capacitance 1 1 This term is analogous to ‘total charge’ suggested by A.N. Frumkin. of tungsten carbide (WC) have been studied on various samples without free carbon content. It was found that the true cd in hydrongen oxidation is about the same for all carbides, independently of the total volume content of carbon, starting materials for carbide preparation, temperature, and other technological parameters of carburization, as well as of the particle size (specific surface) of tungsten carbide. It was also shown that in the anodic polarization of tungsten carbide in H 2SO 4 in the presence of H 2, no true activation, ie no increase in the specific activity, takes place, whereas the observed current rise is due to an increase in the catalyst surface. A close dependence of the total çapacitance on the particle sizes of carbide, in the range of the largest ones (up to smooth WC) up to 0.1 μ dia ( S ≈ 5m 2/g) has been observed. A further decrease of the particle size involved almost no change in capacitance.