(Invited) Exploring Catalyst Characteristics through in-Situ Studies of Solid-Liquid Interfaces

Abstract

Scientists are driven by the urgent need to combat global climate warming and environmental pollution, leading to the development of highly efficient and eco-friendly energy technologies. Hydrogen, a key player in achieving deep decarbonization for net-zero carbon dioxide emissions by 2050, is currently produced through the widely used steam-methane reforming process, which, unfortunately, relies on fossil fuels and generates significant CO2 as a byproduct. This process is environmentally unfriendly and unsustainable, emphasizing the necessity for green hydrogen production. The sun emerges as a clean, renewable, and abundant energy source, offering an ideal solution to the environmental challenges posed by fossil fuels. Hydrogen, an excellent fuel for fuel cell applications, must be generated from renewable and carbon-free resources, particularly utilizing natural energies like sunlight. Enter the photoelectrochemical cell, a promising method for hydrogen generation. This cell comprises semiconductor photoelectrodes capable of harnessing light energy to directly split water. Photocatalysis, leveraging light energy for chemical reactions, holds the key to large-scale solar energy storage, overcoming challenges such as cost and efficiency. Despite over four decades of dedicated research, photocatalysis still faces hurdles in terms of cost and efficiency, hindering progress in this crucial field. A major obstacle lies in the limited understanding of the mechanisms underlying its low performance. To address this challenge, I will overview several experimental studies that have successfully unveiled catalytic reactions at solid/liquid interfaces in real time, focusing on the electrochemical interface of photocatalysis and electrocatalysis. These studies utilize operando X-ray characterization, providing unique insights into the actual reaction mechanisms.