Effect of macro-structure of Ni-based catalysts on methane splitting systems

Methane splitting, also known as methane decomposition or cracking, is an emergent technology to allow swift energy decarbonization since it produces hydrogen without emitting CO2. This work aims at improving hydrogen production from low temperature methane splitting process catalyzed on Ni surfaces. Six different systems were evaluated for their productivity: Ni-foil (pristine and acid treated), Ni particles deposited on α–Al2O3 and on carbon felt, and SiO2-Al2O3-supported Ni catalyst deposited on α–Al2O3 and on carbon felt. Ni-foil displayed negligible hydrogen production even after chemical abrasion treatments were used to increase the surface area. For α–Al2O3 substrates, the coating of Ni/SiO2-Al2O3 vastly outperformed the bulk Ni system (ca. 40 vs 0.011 gH2·gNi–1 total hydrogen production). Depositing bulk Ni on carbon felt improved total hydrogen production to ca. 0.095 gH2·gNi–1. Ni/SiO2-Al2O3 deposited over carbon felt was particularly stable (40 gH2·gNi–1 total hydrogen production), presenting an activity loss rate of ca. 0.011·gH2·gNi–1·h−2, compared to ca. 0.020 gH2·gNi–1·h−2 for the Ni/SiO2-Al2O3 deposited over α–Al2O3. Furthermore, the mechanical integrity of the carbon felt-deposited film was shown to be maintained, while the α–Al2O3-deposited film structure collapsed, due to carbon formation.