Remember the famous Stefan–Boltzmann law and Arrhenius equation in high school chemistry classes? Yes! Based on the fundamental principles of physical chemistry coupled with good foresight, Swedish Nobel Laureate Svante Arrhenius predicted the effects of climate change way ahead of his time in 1896. He proposed that a doubling of anthropogenic CO2 emissions would elevate the world’s temperature by 5 °C to 6 °C, which holds true till today. Closer to our hearts, the United Kingdom also experienced a sweltering 40 °C last summer and was the hottest year since 1884. Therefore, it is imperative that we take progressive steps immediately to tackle climate change.

The concept of renewable energy has since emerged, and solar energy is by far the most promising resource for the future. The amount of sunlight reaching the Earth per hour is more than sufficient to power the world’s yearly energy demand. Solar panels producing clean electricity is currently a popular option (and you might even have one on your rooftop!), but what if we could store that energy in the form of fuels? What if we could convert waste products into useful chemicals?

Photoelectrochemistry does just that! The ‘photo’ component involves a light absorber (think solar panel!) that converts sunlight into electrical energy. However, the process doesn’t stop there. This energy is then passed on to a catalyst to drive an electrochemical reaction. A catalyst is necessary to lower the activation barrier of a reaction and by the Arrhenius equation increases its rate at a specific temperature. Combining both components, we can then perform water splitting to produce hydrogen and power your fuel cell electric cars or reduce carbon dioxide (otherwise a waste byproduct) into chemicals such as ethanol (found in your hand sanitizers and alcoholic beverages!). Yet, much more still needs to be done. Hence, my PhD project aims to improve the performance of state-of-the-art photoelectrochemical systems and hopefully bring this technology to commercialisation one day.

Fun fact: This picture was taken during our NanoDTC Autumn School 2023 to France at the Saint-Clément Aqueduct. Beautiful sunshine!

Celine Wing See Yeung

NanoDTC Associate, a2021