Proceedings of nanoGe September Meeting 2017 (NFM17)
Publication date: 20th June 2016
Photocatalysis has been recognized as a promising route toward large scale solar energy harvesting and storage but has been developing at a frustratingly low pace. The lack of suitable materials is a key challenge that limit its development. To address this issue and realize high-efficiency, low-cost photocatalysis, we need engineered materials with complex functionalities. Understanding how the overall performance of a photocatalyst is influenced by the various material components, especially at the solid/liquid interface, has therefore become critically important. Within this context, we present a systematic study aimed at understanding the detailed processes at the photocatalyst/water interface. In particular, we will discuss whether the application of co-catalysts actually act through the purported mechanism of accelerating charge transfer. To tease out information important to the understanding, we probed the system under quasi-equilibrium conditions as well as under operation conditions using spectroscopic techniques. The study was carried out on three distinct material platforms, iron oxide, bismuth vanadate, and Si (with GaN nanowires). Our results suggest that seemingly similar overall effect by the co-catalysts may be due to fundamentally different reasons. The understanding has been shown to play critical roles in further optimization of photocatalysts. We expect to see increasingly more important roles by similar studies on a wide range of photocatalyst systems.