Author: diyan.wang

Studies of High-Membered Two-Dimensional Ruddlesden-Popper Cs₇Pb₆I₁₉ Perovskite Nanosheets via Kinetically Controlled Reactions

Yi-Chia Chen, Kuan-Chang Wu, Hsin-An Chen, Wen-Hui Chu, Swathi M. Gowdru, Jou-Chun Lin, Bi-Hsuan Lin, Mau-Tsu Tang, Chia-Che Chang, Ying-Huang Lai, Tsung-Rong Kuo, Cheng-Yen Wen, Di-Yan Wang*

Mater. Horiz. 2022, just accepted.

Two-dimensional (2D) all-inorganic Ruddlesden-Popper (RP) perovskites Cs₇Pb₆I₁₉ nanosheets (NSs) were successfully developed for the first time by employing a structural recrystallization process with additional passivation of small organic sulfide molecules. The structure of Cs₇Pb₆I₁₉ NSs are confirmed by powder X-ray diffraction measurements, atomically-resolved STEM measurements and atomic force microscopic (AFM) studies. Cs₇Pb₆I₁₉ NSs with a specific n value of 6 exhibit an unique absorption and emission spectra with intense excitons at 560 nm due to quantum confinement effects in 2D perovskite slabs. The formation mechanisms of 2D Cs₇Pb₆I₁₉ NSs and 3D γ-CsPbI₃ phases were investigated by in-situ photoluminescence (PL) spectroscopy and the activation energies of their formation reactions were calculated to be 151 kJ/mol and 95.3 kJ/mol, respectively. The phase stability of 2D Cs₇Pb₆I₁₉ NSs can be maintained at temperatures below 14 ^oC for more than 4 weeks. The overall results indicate that 2D Cs₇Pb₆I₁₉ NSs demonstrate unique optical properties and structural stability compared with other 3D perovskite materials. We have opened a new path to the future discovery of 2D perovskite structure with metastable phases by using this recrystallization method and the assistance of sulfur-derived organic molecules.

20 May. 2022, our Review Article “Electrochemical Reactions Towards the Formation of Heteroatomic Bonds beyond CO2 and N2 Reduction” has been accepted by Sustainable Energy & Fuels

Shivaraj B. Patil and Di-Yan Wang*

Abstract

Contemporary, electrocatalytic carbon dioxide reduction (CO2RR) and nitrogen reduction reaction (NRR) have gained enormous attention as they are recognised as green and sustainable alternatives for production of various value-added fossil fuels and ammonia (NH3), respectively. Recently, prodigious efforts have been devoted in exploring different catalysts, different products while trying to understand the reaction mechanisms by detecting intermediates using in-situ techniques and density functional theory (DFT) calculations. Currently, the research focus is shifting from obtaining C1 compounds to C2+ compounds on CO2RR and producing NH3 from nitrate (NO3ˉ). Herein, we have summarized various reaction mechanisms reported for producing different compounds including C–C, C–H, and N–H bond formation on CO2RR and NRR. Factors affecting the formation of different compounds on CO2RR is resourcefully illustrated. Furthermore, electrocatalytic formation of heteroatomic C–N bond is exemplified along with reaction mechanisms. Finally, we presented our view on challenges and opportunities in heteroatomic bond formation. This perspective may ignite robust research in developing potential electrochemical systems with dynamic catalysts beyond C–H, N–H, and C–C bond formation.

Dr. Shivaraj Patil received 2021 CSLT, Everlight Chemical Thesis Award in Green Chemistry

https://chemistry.org.tw/news-single.php?mTitle=department&temp_id=724

31 Jan. 2022, Prof. Wang received 2021 CSLT, Outstanding Young Chemical Researcher Award

https://chemistry.org.tw/news-single.php?mTitle=department&temp_id=724