A novel boron nitride supported Pt catalyst for VOC incineration Original Research Article

Low-crystalline hexagonal boron nitride (h-BN) and γ-alumina supported Pt catalysts were employed to investigate the catalytic destruction of volatile organic compounds (VOC). The 0.3 wt.% Pt catalysts were prepared via incipient wetness method using H2PtCl6 as precursor. The oxidation of volatile gasoline was performed in a concentration of 2500 ppmv with volume hour space velocity (VHSV) near 20 000 h−1 from 100 to 500°C. Instead of deactivation, the activity of Pt/h-BN increased significantly in the second run of the oxidation reaction. The light-off temperature (50% conversion) decreased from 210 to 160–170°C in the second run of oxidation. Furthermore, 95% conversion was achieved at less than 200°C. Meanwhile, the Pt/γ-Al2O3 became deactivated in the second run of oxidation. The activity of Pt/h-BN was maintained for three temperature cycles. Long-term oxidation proved that Pt/h-BN activity did not decline over up to 80 h. The positive binding energy shift from XPS revealed that a few boron oxide impurities contaminated on the h-BN surface, these provided the anchorage for the Pt clusters. Metallic Pt surface was oxidized to PtO during the initial oxidation, thus enhancing the oxidation activity. Based on irreversible H2 chemisorption, the platinum dispersion of Pt/h-BN were near 20% and did not change after oxidation at 500°C. Metal sintering was minimal, owing to the high thermal conductivity of h-BN, which prevented any hot spots of oxidation on Pt sites. In sum, experimental results demonstrated that Pt/h-BN was a promising catalyst for VOC destruction.