Zr-promoted Ni nanoparticles in mesoporous silica spheres (NiZr/mSiO2) for catalytic decomposition of methane

Abstract

Catalytic decomposition of methane (CDM) is a promising method for producing carbon nanotubes (CNTs) and H₂ at-scale, with net-zero CO₂ emission. Herein, a highly active CDM catalyst is presented comprised of inert mesoporous silica spheres (mSiO₂) as a support loaded with Ni nanoparticles (NPs) and dopants, resulting in high CH₄ conversion and potential inhibition of tip-growth CNTs. Specifically, uniformly dispersed Ni NPs onto mSiO₂ promoted by scant Zr deposition (rendering NiZr/mSiO₂) exhibited decent reducibility and an excellent H₂ production rate (4.52 mol_H2·g_Ni^–1·h⁻¹ at T = 600 °C and GHSV = 24 L·g_cat^–1·h⁻¹). As the best-performing catalyst, 10Ni0.2Zr/mSiO₂ exhibited satisfactory long-term stability with a low deactivation rate and cyclability performance with marginal activity loss over 10 cycles. Besides, the CNTs growth mode from tip-growth to base-growth could be switched by altering the synthetic chemistry of inert mSiO₂ but at the expense of catalytic activity.