11 Jul. 2023, our work “Kinetic Studies of Oleylamine based 2D-Lead Bromide Perovskite with Controllable n-value by Sequential Addition of Cesium at Room Temperature” has been accepted by Journal of Physical Chemistry C
Invited Article in The Physical Chemistry of Perovskites VSI Virtual Special Issue.
Kinetic Studies of Oleylamine based 2D-Lead Bromide Perovskite with Controllable n-value by Sequential Addition of Cesium at Room Temperature
Anupriya Singh, Yi-Chia Chen, Kuan-Chang Wu, Shih-Mao Peng, Tsung-Rong Kuo, and Di-Yan Wang*
The outstanding properties of lead-based perovskite nanomaterials have led researchers to investigate the potential of their two-dimensional (2D) perovskite counterparts with the chemical formula A’2An+1BnX3n+1. Despite their advantages such as better stability and higher exciton binding energy, the synthesis of phase pure 2D perovskite nanomaterials remains challenge due to the fast nucleation process. Here, we demonstrate a simple and efficient method to synthesize 2D perovskite nanomaterials with phase pure specific n-values. The room temperature nucleation and growth of perovskites with specific n-values are controlled in a two-step synthesis method by the optimized amount of cesium. Our 2D perovskite nanomaterials with specific n-values exhibit high-purity photoluminescence (PL) peaks in the range from deep-blue to azure-blue emission color. X-ray diffraction (XRD) and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) were used to elucidate the kinetic reaction of oleylamine with PbBr2 and the effect of cesium addition in formation of 2D perovskite nanomaterials. In-situ photoluminescence studies were also performed to calculate the activation energy (Ea) of different specific n-value nanomaterials by using the Arrhenius equation. This study not only helps to visualize the effect of addition of Cs amount on the stacking of monolayers of [PbBr6]4-octahedrons, but also provides an easier way to control the n-value in 2D perovskite nanomaterials.
04 May 2023, our work “Efficient Ammonia Photosynthesis from Nitrate by Graphene/Si Schottky Junction Integrated with Ni-Fe LDH Catalyst” has been accepted on J. Mater. Chem. A
Efficient Ammonia Photosynthesis from Nitrate by Graphene/Si Schottky Junction Integrated with Ni-Fe LDH Catalyst
Chun-Hao Chiang, Yu-Ting Kao, Po-Hsien Wu, Ting-Ran Liu, Jia-Wei Lin, Po-Tuan Chen, Jr-Wen Lin, SHAN-CHIAO YANG, Hsuen-Li Chen, Shivaraj B. Patil, Di-Yan Wang* and Chun-Wei Chen*
This work presents the stable and efficient photoelectrochemical (PEC) nitrate-to-ammonia conversion through the facile integration of a graphene/Si Schottky junction and earth-abundant Ni-Fe layered double hydroxide (LDH). Efficient charge separation for photogenerated carriers and large photovoltage generation can be achieved resulting from the graphene/Si Schottky junction photocathode. Through the atomic layer of graphene, the direct growth of Ni-Fe LDH catalyst on the graphene/Si Schottky junction by electrodeposition provides excellent quality at the interfaces between the catalyst and photocathode. The Ni-Fe LDH/graphene/Si Schottky junction photocathode exhibits a promising and stable PEC conversion from nitrate to ammonia, with an optimal onset potential of 0.17 V vs. reversible hydrogen electrode (RHE), the largest saturated photocurrent density of -31.9 mA cm-2, and the highest Faradaic efficiency of 92.5% at 0.15 V vs. RHE. Combined with the several advantages of graphene, such as inherent chemical inertness, high optical transparency, and excellent conductivity, the integration of the semiconductor LDH catalyst on the graphene/Si Schottky junction platform provides an effective strategy to achieve stable and efficient PEC nitrate-to-ammonia conversion.
02 May 2023, Our work “Porifera-like Nickel Nanodendrite for Efficient Electrosynthesis of C-N Compounds from Carbon Dioxide and Nitrate Anions ” has been published on J. Mater. Chem. A
Porifera-like Nickel Nanodendrite for Efficient Electrosynthesis of C-N Compounds from Carbon Dioxide and Nitrate Anions
Shivaraj B. Patil,1# Chang-Ru Lee,1# Swathi M. Gowdru,1# Chun-Chih Chang,2* Shu-Ting Chang,1 Yi-Chia Chen,1 Kuan-Chang Wu,1 Chia-Che Chang,1 Shu-Chih Haw,3 Di-Yan Wang1*
Generating high-energy compounds with heteroatomic bonds by using electrochemical reaction has attracted interest due to the high desire to achieve a net zero carbon state. In this dimension, heteroatomic compounds such as acetamide (CH3CONH2) was successfully produced along with formation of ethylene glycol and other C2+ compounds by integrating CO2RR with nitrate reduction reaction (NtRR). Highly porous nickel nanodendrites (p-Ni NDs) with porifera architecture was constructed by electrodeposition method and subsequent etching process. In the electrolyte of 0.05M KNO3 and 0.5 M KHCO3, p-Ni NDs can generate acetamide and ethylene glycol at the yield rate of 657 µg/h/cm2 and 640 µg/h/cm2 with FE of 23.2% and 18.0% under applying a voltage of -0.3 V vs RHE, respectively. 1H NMR was extensively used to detect and quantify the products. During the reaction, the surface of p-Ni NDs remains the metallic state which was confirmed by several X-ray spectroscopic techniques. Density functional theory (DFT) calculations revealed that *COHCOH(a) is the crucial intermediate in obtaining acetamide. Both experimental and theoretical experiments substantiate high activity of p-Ni NDs towards acetamide formation via C–N coupling.