Transcending catalytic limits for methane decomposition: multi-functional basalt fiber-supported catalysts with membrane synergy

Abstract

Catalytic methane (CH₄) decomposition (CDM) offers a direct pathway for hydrogen (H₂) gas production and valuable carbon nanotube (CNT) synthesis. However, the stability of this gas-to-solid reaction is hindered by limitations in CNT growth and reactor volume constraints. Departing beyond conventional nanopowder catalysts, we introduce basalt fiber-supported Ni/LTA catalysts that feature CO_x-free H₂ generation and up to 3.7 times longer CDM reaction times, delivering an H₂ production rate of 3.1 mol g_Ni⁻¹ h⁻¹ over 22 h at 500 °C, surpassing Ni/LTA nanopowder counterparts. The basalt fiber catalysts exhibit uniform and robust CNT growth, along with sustained and stable H₂ generation lasting up to three times longer relative to traditional CDM catalysts that deactivate within 10 h as reported in the literature. Integration of the flexible basalt fiber catalysts into an H₂-permeable LTA-Pd membrane reactor further enhances the reaction time by 36% and CH₄ conversion by 40%, achieving up to 45% CH₄ conversion over 27 h, surpassing expected equilibrium conversion rates. The excellent catalytic stability of the 10 wt% Ni/LTA basalt fiber catalyst is additionally showcased through multiple reduction-800 °C CDM reaction-CO₂ regeneration cycles. This transformative study propels the development of functional catalyst materials, revolutionizing thermocatalytic processes.

Graphical abstract

A basalt fiber-supported LTA zeolite-based nickel catalyst advances methane decomposition, yielding CO_x-free hydrogen, multi-wall carbon nanotubes, and extensive reaction time.