Propylene oxide (PO) is a highly valuable chemical intermediate used in a wide range of industries. The traditional methods of producing PO have several drawbacks, including high cost and limited reserves of the noble metal catalysts used. In light of this, a research team led by Prof. Chen Xinqing from the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences has made significant strides in developing non-noble catalysts for propylene epoxidation.
The conventional methods of producing propylene oxide involve complex and costly processes. However, the direct epoxidation of propylene with hydrogen (H2) and oxygen (O2) offers a greener, more efficient, and sustainable approach. The current catalyst used in this process, Au catalyst, is not only expensive but also has limited reserves. Hence, the need for highly-active non-noble catalysts has become urgent.
The research team’s breakthrough lies in the development of non-noble nickel catalysts supported on titanium silicate-1 (TS-1) zeolite. This novel catalyst exhibits excellent catalytic performance in the gas-phase epoxidation of propylene. The researchers synthesized a series of non-noble Ni/TS-1 catalysts using the deposition precipitation method. They discovered that the strong metal-support interaction between nickel nanoparticles and TS-1 was the key to their catalyst’s success in propylene epoxidation.
One particular catalyst, the 2% Ni/TS-1, stood out among the others. It achieved a remarkable PO selectivity of 76.8% and a PO production rate of 151.9 g PO/(h·Kgcat). Even more impressive was its long-term stability at 200 °C, lasting over 20 hours. These results highlight the potential of non-noble nickel catalysts as a viable alternative to the currently used expensive and limited noble metal catalysts.
To gain insights into the reaction mechanism and further enhance the catalyst’s performance, the researchers conducted various characterizations using in-situ technologies. Through these studies, they discovered that metallic nickel played a crucial role in promoting the reaction between hydrogen and oxygen, leading to the in-situ synthesis of hydrogen peroxide (H2O2). This H2O2 then oxidized propylene to propylene oxide (PO). Theoretical calculations also revealed that the presence of a passivation layer on the nickel surface enabled the production of H2O2, further enhancing the catalyst’s efficiency.
The development of highly-active non-noble nickel catalysts supported on TS-1 zeolite presents a promising avenue for achieving sustainable propylene epoxidation. Not only do these catalysts offer a more cost-effective and abundant alternative to noble metal catalysts, but they also demonstrate impressive catalytic performance and long-term stability. Furthermore, the in-depth understanding of the reaction mechanism through various characterizations opens up possibilities for further optimization and improvement of these catalysts.
The research conducted by Prof. Chen Xinqing and his team at the Shanghai Advanced Research Institute (SARI) offers new hope for the production of propylene oxide. Their development of non-noble nickel catalysts supported on TS-1 zeolite holds the promise for a green, efficient, and sustainable approach to propylene epoxidation. With their remarkable catalytic performance and long-term stability, these catalysts have the potential to revolutionize the propylene oxide industry, paving the way for a more sustainable future.
Leave a Reply