Time: July 11th, 2019，9:00am
Venue: 3rd Floor Conference Room, State Key Laboratory of Catalysis
Lecturer: MA Yimeng, Donghua University
The development of photoelectrochemical (PEC) water splitting systems has been progressed from the (photo-) catalyst design towards fabricating practical stand-alone devices in last decade. In my talk, I will introduce our research activities at HZB in fabricating integrated devices using metal oxide photoelectrodes beyond the lab-scale experiments. In particular, we demonstrate a BiVO4-based water splitting device in tandem with Si solar cells on different physical scales. On the small-scale device (i.e. 0.24 cm2), the system shows high solar-to-hydrogen (STH) efficiency (5.5 %), setting the benchmark for our next step on upscaling. However, the STH drops significantly to 2.1 % in the upscaled system using 50 cm2 BiVO4 photoanodes, although this is the highest reported value for a large-area (> 10 cm2) BiVO4-based water splitting device. By performing a series of control experiments, we find that the 50 cm2 BiVO4 remained its high catalytic activity, but other unexpected factors play a dominant role in this efficiency drop, such as substrate conductivity, electrolyte conductivity, and cell geometry. These factors result in a total voltage loss is 600 mV and therefore limit the performance of the large-area photoanodes. Our results illustrate the challenges involved in the scale-up of solar water splitting devices and underline the importance of increased electrochemical engineering efforts in this developing field.
MA Yimeng obtained his BSc in chemistry from Lanzhou University in 2009. Then he moved to University College London and London Centre for Nanotechnology to pursue his MSc degree in nanotechnology. In 2011, he joined Prof James Durrant’s group at Imperial College London as a PhD student, working on using time-resolved spectroscopies and electrochemistry to understand charge charrier dynamics of metal oxide photoelectrodes (with special focus on BiVO4). In 2016, he moved to Helmholtz-Zentrum Berlin and worked as a postdoc chemist in Prof Roel van de Krol’s group to extend his BiV4 knowledge from catalysis to device engineering and upscaling. Since 2019, he became a research fellow at Donghua University, working on extending the application of PEC water splitting towards more industrial-driven applications.
Contact: ZHENG Min, DNL16