A team of researchers has discovered a new way to make valuable industrial chemicals from propylene using a common, low-cost material: lead dioxide (PbO₂).

Their findings reveal that the oxygen atoms inside the catalyst itself play a direct and active role in the chemical reaction. This discovery opens the door to more sustainable and affordable methods of producing key ingredients for everyday materials such as plastics, clothing fibers, and insulation foams.

Details of the findings were published in the journal Catalysis Science & Technology on October 7, 2025.

"Traditionally, the oxidation of propylene relies on noble metals like platinum and palladium, rare and expensive metals whose extraction leaves a sizeable footprint," points out Hao Li, a professor from Tohoku University's Advanced Institute for Materials Research (WPI-AIMR) who led the study. "Moreover, current industrial oxidation processes often use hazardous oxidants such as chlorine or peroxides, creating serious safety and waste-disposal challenges."

Li and his team set out to find a safer and greener alternative. Their research shows that lead dioxide, a non-noble metal oxide, can effectively catalyze the oxidation of propylene when powered by electricity. Instead of relying on external oxidants, the oxygen for the reaction comes directly from within the crystal lattice of the PbO₂ catalyst itself.

The process works like a rechargeable battery that lends out its stored power and then refills itself. Here, the catalyst "lends" oxygen atoms from its structure to drive the reaction and then "recharges" by pulling fresh oxygen from water in the system. This built-in recycling loop keeps the reaction running efficiently and cleanly without the need for hazardous chemicals.

The researchers confirmed this unique mechanism using advanced "in-situ" techniques that allow them to observe chemical processes as they happen. Through electrochemical attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, they identified key reaction intermediates forming on the catalyst's surface. At the same time, differential electrochemical mass spectrometry (DEMS) provided direct evidence that lattice oxygen actively participates in the oxidation reaction.

"Our goal was to understand how non-noble metals can do the same chemistry as noble ones, but in a more sustainable way," adds Li. "By showing that lattice oxygen plays an active role, we've opened new possibilities for designing catalysts that are both efficient and environmentally friendly."

This work does more than prove a new reaction mechanism; it also validates theoretical predictions that scientists have proposed for years but struggled to verify experimentally. By combining cutting-edge techniques with careful control of reaction conditions, the team provided a clear picture of how oxygen vacancies and lattice oxygen interact during electrochemical oxidation.

Looking ahead, the researchers plan to fine-tune their catalyst design. They aim to modify the electronic structure of lead dioxide through doping and oxygen-vacancy engineering, exploring how different metals and vacancy levels affect the reaction's efficiency and selectivity.

All experimental and computational data from this study are available through the Digital Catalysis Platform, a publicly accessible database developed by the Hao Li Lab to support open scientific collaboration and catalyst design worldwide.

Publication Details:

Title: Probing the Reactivity of In-Situ Formed Oxygen Vacancies of Non-Noble Lead Oxides for Anodic Propylene Oxidation

Authors: Jia Ge, Tian-Yi Wang, Xiao-Long Zhang, Hongyu Sun, Renying Wang, Peng-Cheng Yu, Xiandi Sun, Shu-Ping Sun, Hang Liu, Yu Liu, Chuan-Ling Zhang, Bo Da, Ya-Rong Zheng, Min-Rui Gao, and Hao Li

Journal: Catalysis Science & Technology

DOI: 10.1039/D5CY01032B