报告题目：Unveiling the material’s photo/electrochemical properties correlated with its electronic structures

报告人：苏大为 教授 （墨尔本皇家理工大学）

邀请人：田宏伟 教授

主持人：田宏伟 教授

报告时间：2024年7月17日 10：00-11：00

报告地点：中心校区唐敖庆楼D区429会议室

主办单位：汽车材料教育部重点实验室，437ccm必赢国际

报告摘要：Structure (from atomic and electronic level)-performance correlation demonstrates the crucial impact of complex surface chemistry and nanostructure on photo/electrochemical performance, which is also a persistent barrier for rationally designing photo/electrode materials. To rational design materials for their superior photo/electrochemical properties can only rely on the unveiling of the correlation between their electronic structures' evolution along the testing processes. Therefore, from the electronic level to develop the spatial- and time-resolved light interaction technology can the photo/electrochemical reactions processes be deeply understood. Therefore, here I showcase several recent works about investigating the intrinsic properties of the materials correlated with their subtle micro-structure variation, including,

1.Through a combination of theoretical calculations and experiments, I recently revealed how water molecules drive moisture electric generators (MEGs) in three main ways: 1). Water molecules are absorbed on the material's surface and split into hydroxy groups and protons due to the material's polarizability and static electric potential. This process changes the electrochemical potential of the materials. 2). Protons from the water splitting act as charge carriers. 3). Hydrogen bonds in water molecules help drive these charge carriers between electrodes, maintaining the current flow.

The study shows that anatase TiO2 materials can change output voltage based on differences in work function, influenced by surface adsorbed species and the material's crystal facets. This work clarifies the general working principle of MEGs.[1]

2.The heterojunction approach enhances photoelectric current for reactions like hydrogen evolution by improving the separation of photogenerated electrons and holes through proper band alignment between two materials. Most research focuses on different bulk nanomaterials, but few examine crystal structure effects. I unveiled a new way to optimize band alignments in heterogeneous catalysts for better photoelectric properties by looking at polyheptazine-structured g-C3N4 and wurtzite CdS. It finds that higher annealing temperatures make CdS expose its (110) facets, forming an S-scheme heterojunction with g-C3N4. This junction speeds up electron-hole recombination and enhances their separation, improving photocatalytic hydrogen evolution reaction (HER) performance.[2]

3.Ion transfer issues and chemical instability in Zn anodes cause dendrites and side reactions. I recently introduced a Bi/Bi2O3 hybrid interphase that: 1) Protects the interface to suppress side reactions. 2). Prevents dendrite formation by favorably dissociating Zn atomic clusters. The Zn@Bi/Bi2O3 cell achieves high plating capacity (1.88 Ah cm-2 at 5 mA cm-2) and lasts over 300 hours at high current density. The Zn@Bi/Bi2O3||MnO2 full-cell retains 86.7% capacity after 500 cycles at 1 A g-1, outperforming most interphases. The scaled-up battery (6 V, 1 Ah) combined with a photovoltaic panel shows excellent energy storage and long output (12 h). This approach promises ultrastable Zn anodes and applications in other metal-based batteries.[3]

References:

[1] Advanced Energy Materials. First published: 14 May 2024 https://doi.org/10.1002/aenm.202400590

[2] Advanced Functional Materials. First published: 19 May 2024 https://doi-org.ezproxy.lib.uts.edu.au/10.1002/adfm.202404585

[3] Advanced Materials. Volume36, Issue19 May 9, 2024, 2400237

报告人简介：

Dawei Su is a full professor in Applied Chemistry & Environmental Science at the School of Science, STEM College, RMIT University. Prof. Su has shown himself to be extremely capable in both Teaching and Research and the interplay of theory, best practice and experimental cutting-edge research. Dawei has a background in material science. His research relates to advanced energy storage, conversion, and catalytical hydrogen evolution. His unique background allows him to integrate materials science and physics with chemistry and nanotechnology. This synergy combines his expertise in experimental work (synthesis, characterization, quantitative analysis) and atomic-scale and electronic-scale theoretical investigations (quantum chemistry, density functional theory and Ab Initio molecular dynamics).

He is leading the research programs (ARC DECRA, DP, LP, LIFE’s and ARENA, CRC, amongst others) centred on unveiling the material’s electrochemical or photochemical properties correlated with their electronic structures via the combination of in-situ spectroscopies and theoretical investigations. He has driven fundamental advances in designing chemically and structurally tunable materials and uncovering the impact of materials’ properties on electro(photo)chemical performance.