Efficient Methanol-to-Olefins Conversion Via Photothermal Effect Over TiN/SAPO-34 Catalyst

As one of the most promising routes for production of low-carbon olefins (e.g., ethene and propene etc.), methanol-to-olefins (MTO) reaction is influenced largely by the temperature. Noble metal (e.g., Au, Ag, etc.) nanoparticles are known to exhibit the localized surface plasmon resonance (LSPR) effect, which has been applied in photothermal reactions. Owing to the increased light absorption ability in near-infrared region, titanium nitride (TiN) nanoparticles exhibit a superior LSPR effect over noble metals. Herein, we report on the MTO reaction via photothermal effect over a series of TiN(x)/SAPO-34 (x = 0.5, 0.75, 1, 2, 5, 10, 13 wt%) catalysts prepared by a simple mechanical grinding method. The MTO reaction over TiN(x)/SAPO-34 was carried out under a 300 W xenon lamp irradiation. The MTO reactivity of TiN(x)/SAPO-34 was influenced by both the photothermal temperature from the LSPR effect of TiN nanoparticles and the Bronsted acid sites on SAPO-34, both of which were dependent on the loading amount of TiN nanopartiles. The synergistic effect of high photothermal temperature, sufficient Bronsted acid sites and moderate BET surface area gave rise to the optimal catalytic performance of MTO reaction over TiN(10)/SAPO-34, which exhibited a methanol conversion of 73.1% and an ethene selectivity of 62.5%.