Propylene oxide (PO) is a chemical intermediate with a high added value. Direct epoxidation of propylene using H2 and O2 is a green, efficient, and sustainable alternative to traditional methods of producing PO. However, the present Au catalyst employed in this process is expensive and has limited reserves. As a result, developing extremely active non-noble catalysts for propylene epoxidation is critical.
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Prof. Xinqing Chen of the Chinese Academy of Sciences’ Shanghai Advanced Research Institute (SARI) suggested non-noble nickel catalysts facilitated by titanium silicate-1 (TS-1) zeolite, which displays superior catalytic activity in the gas-phase epoxidation of propylene.
The study's findings were published in the journal ACS Catalysis.
Using the deposition precipitation approach, the researchers created a variety of non-noble Ni/TS-1 catalysts. They discovered that the strong metal-support contact between Ni nanoparticles and TS-1 was responsible for their high catalytic activity in propylene gas-phase epoxidation.
The 2% Ni/TS-1 catalyst developed achieved a high PO selectivity of 76.8% and a PO production rate of 151.9 g PO/(hKgcat). Its long-term stability at 200 °C was more than 20 hours.
Furthermore, using in-situ technologies, the researchers studied several characterizations of the catalyst to understand the reaction process. Metallic Ni stimulated the reaction between hydrogen and oxygen for the in-situ creation of H2O2 and then oxidized propylene to PO, according to the results. Theoretical simulations demonstrated that the Ni surface passivation layer facilitated the formation of H2O2.
Journal Reference:
Li, W., et al. (2023) Highly Efficient Epoxidation of Propylene with In Situ-Generated H2O2 over a Hierarchical TS-1 Zeolite-Supported Non-Noble Nickel Catalyst. ACS Catalysis. doi:10.1021/acscatal.3c02206.
Source: https://english.cas.cn/