Insight into the moderate interaction between the metal and support and reinforcing of Ni/SiO2-based catalysts efficiency with the manganese integration in thermal catalytic methane decomposition

Abstract

Developing an environmentally friendly and highly efficient catalyst is crucial for generating clean hydrogen without CO_x and structured carbon. The catalytic decomposition of methane encourages technology to convert natural gas into these valuable products. For this purpose, surface defects in activating CH₄ have garnered much interest in developing silica-supported nickel catalysts by maintaining active sites and modulating metal-support interaction (MSI). Thus, It is shown here that the presence of Mn improved the reducibility of superficial NiO and created a moderate interaction between Ni and the support, decreasing the electron density around the Ni atom and elevating surface oxygen species’ presence by introducing lattice defects, thus facilitating the reduction, promoting the dissociation of methane on the nickel surface and enhancing the reactivity of the reaction Consequently, this MSI modulate stabilized the active sites, preventing quick sintering under reaction conditions. Based on TEM analysis, the surface morphology revealed well-dispersed metallic Ni and the restriction of Ni crystal growth. The strong metal-support interaction resulted in a high carbon diffusion driving force, providing more sites for growth in carbon nanofiber (CNFs). Maintaining the balance between the infiltration of dissolved carbon and the expansion of CNFs while also preventing the deactivation of the catalyst due to the covering of active sites by channeling carbon deposits towards the edges of the active sites and oxidation of coke produced by active oxygen species, all showed the effective presence of manganese in the catalyst’s configuration.