Strengthening the metal-support interaction over Pt/SiO2-TiO(OH)2 by defect engineering for efficient dehydrogenation of dodecahydro-N-ethylcarbazole

Liquid organic hydrogen carriers (LOHC) are considered as the promising candidates for large-scale hydrogen storage. The N -ethylcarbazole/dodecahydro- N -ethylcarbazole (NECZ/12H-NECZ) system has received increasing attention due to its excellent comprehensive properties in the hydrogen storage candidates. In this work, the Pt/SiO 2 -TiO(OH) 2 catalysts are synthesized and show good activity, selectivity and stability for 12H-NECZ dehydrogenation reaction. Among them, the 2.5 wt% Pt/SiO 2 -TiO(OH) 2 catalyst shows the best dehydrogenation performance with 5.75 wt% H 2 release amount and 98 % selectivity of NECZ. Combined with XRD, HRTEM, ATR-FTIR, XPS and EPR analysis, it is found that the oxygen vacancy concentration in Pt/SiO 2 -TiO(OH) 2 is significantly enhanced due to the formation of Si-O-Ti species compared with Pt/SiO 2 and Pt/TiO(OH) 2 , which strengthens the SMSI (strong metal-supporting interaction) effect between metal Pt and support SiO 2 -TiO(OH) 2 . The optimized d-band center of catalyst is beneficial for accelerating the sluggish kinetics of the rate-limiting step of the whole dehydrogenation reaction. Furthermore, compared with the results by replacing SiO 2 with Al 2 O 3 or CeO 2 , it is indicated that the introduction of oxides mainly plays the role of regulating the surface electronic state of TiO(OH) 2 and increasing the oxygen vacancy concentration.