(319f) H2 Production Via Catalytic Decomposition of Methane Using a Highly Durable Catalyst

Catalytic decomposition of methane (CDM) is an efficient approach to convert methane, a potent greenhouse gas, into CO₂-free hydrogen and carbon products. Since catalyst deactivation is inherent to CDM catalyst due to constant carbon deposition, there is a continued interest in developing active catalysts with either high durability or high regenerability. Nickel is the most frequently investigated active metal for CDM. However, most Ni-based catalysts reported to date exhibited limited durability.

Herein, we present a highly durable and high-performance Ni-based catalyst for CDM, consisting of SiO₂ supporting metallic nickel that are decorated and dispersed uniformly on the SiO₂ support surface. Although the synthesis procedure is relatively simple, our catalyst (SiO₂@Ni) can perform up to 70 h at an average CH₄ conversion of 15% at WHSV=4.5 L·kg·h^–1 under a concentrated methane feed (P_CH4 = 0.9 atm). The steady-state H₂ production rate was found to be 0.057 mol·h^–1·g_cat^–1 while the total carbon yield was 23.5 g_C/g_cat, surpassing many reported catalysts to date. It is also demonstrated that a brief hydrogen reduction step can have a significant impact over the catalytic performance compared to the as-synthesized catalyst directly used in the reaction. Compared to other tested compositions (SiO₂@Co and bimetallic SiO₂@NiCo), monometallic Ni showed better performance. With tip-growth as the dominant mechanism, SiO₂@Ni is a promising candidate for single-use catalyst with a long lifetime and high carbon yield.