Professor PJ Cullen is a Professor in the School of Chemical and Biomolecular Engineering, Faculty of Engineering, at the University of Sydney, having joined the institution in 2019. He obtained his bachelor's degree and PhD from University College Dublin, Ireland. Prior to this appointment, he held the position of Group Head of the Food, Water, Waste Research Group at the University of Nottingham, United Kingdom. Professor Cullen also served as CEO of PlasmaLeap Technologies and Technology Director at Innopharma Labs in Dublin, after spending ten years at the Dublin Institute of Technology lecturing and coordinating process engineering research.

A leading expert in plasma engineering, Professor Cullen specializes in cold plasma technologies and high-powered lasers for plasma-biological applications. His research investigates how cold plasma interacts with biological materials to enable applications in food preservation, water treatment, crop growth, biomass and gas conversion, and cancer treatment, while protecting biomolecules from thermal damage. He further explores hotter plasmas for elemental analysis using lasers to achieve real-time detection of heavy metals and chemicals in food, medicine, and the environment. Key recent achievements include developing a plasma-electrolysis process to produce gaseous ammonia directly from air, mimicking lightning for sustainable green ammonia as a hydrogen carrier and carbon-free fuel, and advancing non-thermal plasma methods to convert landfill methane emissions into long-chain hydrocarbons suitable for sustainable jet fuel. With over 190 journal articles published, he has edited influential books such as "Cold Plasma in Food and Agriculture: Fundamentals and Applications," "Novel Thermal and Non-Thermal Technologies for Fluid Foods," "Process Analytical Technology for the Food Industry," and "Food Mixing: Principles and Applications." Recognized as a Clarivate Highly Cited Researcher in 2017, 2018, and 2025, Professor Cullen has commercialized plasma innovations through PlasmaLeap Technologies and engages in multidisciplinary efforts at the University of Sydney's Net Zero Institute and Sydney Institute of Agriculture.

Professional Email: patrick.cullen@sydney.edu.au