Wet-kneading synthesis of silica-supported nickel catalyst to promote reversible hydrogen storage of N-ethylcarbazole

Hydrogen energy is regarded as an ideal energy carrier due to its advantages such as high energy density, environmental friendliness, and wide availability. The storage and release of hydrogen using liquid organic hydrogen carriers (LOHCs) such as N-ethylcarbazole (NECZ) offer distinct advantages for safe hydrogen transport and storage. Developing efficient catalysts for this reversible process remains a critical challenge. At present, the high cost of noble metal catalysts hinders their widespread application, and most of the non-noble metal catalysts are not efficient in reversible hydrogenation storage of NECZ. In this study, a silica supported non-noble Ni was prepared by the wet-kneading method, which successfully achieved the reversible hydrogen storage of NECZ. The catalyst exhibited high activity and moderate stability, achieving hydrogen storage of 5.77 wt% within 6 h under 6 MPa of H 2 at 150 °C, and hydrogen release of 5.77 wt% within 1.5 h at 200 °C during 5 cycles. XPS studies identified Ni 0 as the main active site for hydrogenation-dehydrogenation cycles. IR and kinetic studies further revealed that same Ni 0 sites are poisoned by the intermediate 4H-NECZ. This work might pave the way for designing high-performance non-noble catalysts for reversible chemical hydrogen storage.