Deciphering transient carbon footprint for methane dry reforming over Ni@S-1 nanosheet zeolite catalyst

Abstract

Carbon deposition, an inevitable product operated at high temperatures, is a headache-inducing obstacle to enhance catalyst stability for methane dry reforming (MDR). Herein, we have ingeniously designed sintering-resistant Ni@S-1 nanosheet zeolites to purposefully induce common linear and non-linear deactivation of catalysts during MDR reaction for deciphering carbon footprint. Multiple evidences unveiled that "transient carbon", composed of multi-phenyl-rings via rapidly rearrangement of CHx* fragments, was a crucial vane for catalyst deactivation. Accordingly, we proposed a dynamic equilibrium theory for the generation and elimination of "transient carbon". Achieving this balance was dependent of the matching degree between Ni0 nanoparticles and NiOx(OH)y, which both separately originated from the evolutions of 1:1 and 2:1 Ni phyllosilicates controlled by nanosheet thickness. Delightfully, synthetic Ni@S-1–60nm catalyst with an optimal ratio of Ni0/NiOx(OH)y contributed higher MDR activity and durability. These findings derived a new MDR reaction pathway and afforded value-filled information for developing high carbon-resistant MDR catalysts.