Ni@ZSM-5 catalyst prepared by direct synthesis for efficient hydrogen production through the water-gas shift reaction

A nickel-based ZSM-5 zeolite catalyst was synthesized via a one-pot approach for the hydrogen production via the water-gas shift reaction. Comprehensive characterization was performed using several complementary techniques. The presence of Ni species exhibiting different interactions with the support was evidenced by temperature-programmed reduction and near-ambient-pressure X-ray spectroscopy experiments. To compare performance, a catalyst with the same Ni loading was prepared via incipient wetness impregnation; both catalysts were active and selective for the water-gas shift reaction at 400 °C and 1 atm. Notably, the one-pot-synthesized catalyst, Ni2.4@ZSM-5, achieved higher CO conversion than the wet-impregnated catalyst, remained stable over 48 h of continuous operation (as shown by stability and on-off cycling tests), and exhibited high hydrogen selectivity. In situ DRIFT and NAP-XPS spectroscopy further revealed transient species, providing insights into the reaction mechanism.