Author: diyan.wang

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*

https://doi.org/10.1039/D3TA01169K

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.

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*

 

https://doi.org/10.1039/D3TA00438D

 

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.

 

Near-infrared phototheranostic iron pyrite nanocrystals simultaneously induce dual cell death pathways via enhanced Fenton reactions in triplenegative breast cancer

Chunhua Zhao#, Zekun Liu#, Chia-Che Chang, Yi-Chia Chen, Qize Zhang, Xiao-Dong Zhang, Chrysafis Andreou, Jiadong Pang, Ze-Xian Liu *, Di-Yan Wang*, Moritz F.Kircher, Jiang Yang*

Triple-negative breast cancer (TNBC) is considered more aggressive with a poorer prognosis than other breast cancer subtypes. Through systemic bioinformatic analyses, we established the ferroptosis potential index (FPI) based on differentially expressed ferroptosis regulatory genes and found that TNBC has a higher FPI than non-TNBC in human breast cancer cell lines and tumor tissues. To exploit this finding, we developed biologically-amenable phototheranostic iron pyrite (FeS₂) nanocrystals (NCs) that efficiently harness near-infrared (NIR) light, as in photovoltaics, for multispectral optoacoustic tomography (MSOT) and photothermal therapy. Upon NIR irradiation that thermodynamically enhances Fenton reactions, dual death pathways of apoptosis and ferroptosis are simultaneously induced in TNBC cells, comprehensively limiting cancer survival by regulating p53, FoxO, and HIF-1 signaling pathways and attenuating a series of metabolisms, including glutathione and amino acids. As a unitary phototheranostic agent with a safe toxicological profile, the nanocrystal represents an effective way to circumvent the lack of therapeutic targets and propensity of metastatic progression in TNBC and simplifies a streamlined workflow of cancer management with an integrated image-guided intervention.

Fast Charge Transfer between Iodide Ions and Delocalized Electron System on the Graphite Surface for Boosting Hydrogen Production. just accepted by J. Mater. Chem. A

Shih-Mao Peng,¹ Shivaraj B. Patil,¹ Chun-Chih Chang,² Shu-Ting Chang,¹ Yi-Chia Chen,¹ Kuan-Chang Wu,¹ Wei-Nien Su,^3,4* Bing Joe Hwang,^4,5,6* Di-Yan Wang¹*

Developing new catalysts to reduce the energy barrier for hydrogen production from water splitting has been an important research topic. It is well-known that the water-splitting voltage is limited by a theoretical potential of 1.23 V of oxygen evolution reaction (OER). Recently, a new electrolytic method using iodide oxidation reaction (IOR) instead of OER has been proposed to produce valuable chemical iodine and hydrogen efficiently by a reduced operating voltage. In this work, we found that the graphite-based materials with a delocalized p electron system exhibited fast charge transfer with physically adsorbed iodide ions, thus revealing desirable IOR catalytic activity. The carbon fiber paper with a graphite structure was chosen as the catalyst and exhibited the onset potential of 0.54V (vs. RHE) for IOR, which is close to the standard potential of iodide oxidation. Also, the CFP demonstrated a minimum Tafel slope of 47.78 mV/dec in the electrochemical reaction with significant stability at the current density of 10 mA/cm² for over 18 hours. Moreover, in a two-electrode system, a cell voltage of only 0.59 V was required to provide a current density of 10 mA/cm⁻² for the IOR and hydrogen evolution reaction (HER). Based on energy costs, our HER and IOR system can reduce energy consumption by 65% compared to conventional OER-based water electrolysis. The overall results indicate that our findings pave a new route to facilitate the industrial application of hydrogen production via electrochemical reactions.