Intrinsic kinetics in carbon gasification: Understanding linearity, “nanoworms” and alloy catalysts

Abstract

There is good evidence that understanding the kinetics of catalytic carbon gasification involves the use of Fick's Law at nano-level, to evaluate the relative rates of the three main steps: (1) carbon dissolution; (2) carbon bulk diffusion through the catalyst and (3) surface reaction. Intrinsic kinetics should be handled taking that into account. When we observe linearity in the weight vs. time dependence up to more than 50% conversion this is a strong indication that a carbon bulk diffusion mechanism is operating. The peculiar behavior of moving catalyst nanoparticles observed under in-situ microscopy is also explained by the same mechanism. Occurrence of synergetic effects with alloys may be due to facilitating one or more of the three steps.