Nanomaterials
·
2023
·Vol. 13
·期 3
·444
·
IF 5.3
Min Li,Feng Liu,Supeng Pei,Zongshang Zhou,Kai Niu,Jianbo Wu,Yongming Zhang
Platinum-based catalysts are widely used for efficient catalysis of the acidic oxygen reduction reaction (ORR). However, the agglomeration and leaching of metallic Pt nanoparticles limit the catalytic activity and durability of the catalysts and restrict their large-scale commercialization. Therefore, this study aimed to achieve a uniform distribution and strong anchoring of Pt nanoparticles on a carbon support and improve the ORR activity and durability of proton-exchange membrane fuel cells. Herein, we report on the facile one-pot synthesis of a novel ORR catalyst using metal–nitrogen–carbon (M–N–C) bonding, which is formed in situ during the ion exchange and pyrolysis processes. An ion-exchange resin was used as the carbon source containing R-N+(CH3)3groups, which coordinate with PtCl62−to form nanosized Pt clusters confined within the macroporous framework. After pyrolysis, strong M-N-C bonds were formed, thereby preventing the leaching and aggregation of Pt nanoparticles. The as-synthesized Pt supported on the N-doped hierarchically porous carbon catalyst (Pt/NHPC-800) showed high specific activity (0.3 mA cm−2) and mass activity (0.165 A mgPt−1), which are approximately 2.7 and 1.5 times higher than those of commercial Pt/C, respectively. The electrochemical surface area of Pt/NHPC-800 remained unchanged (~1% loss) after an accelerated durability test of 10,000 cycles. The mass activity loss after ADT of Pt/NHPC-800 was 18%, which is considerably lower than that of commercial Pt/C (43%). Thus, a novel ORR catalyst with highly accessible and homogeneously dispersed Pt-N-C sites, high activity, and durability was successfully prepared via one-pot synthesis. This facile and scalable synthesis strategy for high-efficiency catalysts guides the further synthesis of commercially available ORR catalysts.Keywords:fuel cell;electrocatalyst;ion exchange;Pt-N-C bonding;oxygen reduction reaction
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Henan Jia,Pei Su,Jiahang Fan,Taotao Guo,Yiming Zhang,Lingfen Miao,Lei Wan,Penghui Yang,Mao-Cheng Liu
Yolk-shell-structured transition metal sulfides (TMSs)/carbon nanocomposites are highly desirable in advanced energy storage system, such as sodium-ion batteries (SIBs) and supercapacitors (SCs). Nevertheless, practical applications are still prevented by the loose attachment of TMSs with carbon caused by conversion stress, the aggregation of TMSs nanoparticles and the sluggish ion transport caused by high crystallinity of carbon. Here, the disperse hollow Co 9 S 8 nanoparticles encapsulated into N,S-codoped carbon nanotubes (CNTs) with poor crystallinity through Co N C bond was synthesized (CS-NSCNT) to overcome the above obstacles. The designed CS-NSCNT can provide the short diffusion path and prevent the huge volume expansion of conversion reaction. Moreover, the established Co N C bond endows the strong interaction and regulates the electronic structure thus promote the stability and rate performance effectively. The CS-NSCNT SCs’s electrode delivers a high specific capacitance of 1150 F g −1 at 1 A g −1 , with a high cycling life stability and rate performance. For SIBs, the CS-NSCNT cathode demonstrates an initial reversible capacity of 475 mAh g −1 at 0.1 A g −1 and an excellent rate performance with a capacity retention of 53 % at 10 A g −1 . This work may satisfy the long-stability, high-capacitance/capacity, high-power/energy density application requirements of future applications.
研究领域:
材料科学
·
能源存储技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
TETRAHEDRON
·
2020
·
IF 2.233
Zhen-Hua Li,Xiao-Meng Sun,Jin-Jing Qin,Zhi-Yong Tan,Wen-Biao Wang,Yao Ma
An efficient and divergent synthesis of N -arylbenzimidazoles and N -arylindazoles from arylamino oximes based on reaction conditions selection was developed. The synthesis was approached by treating oximes with BTC and the chemoselectivity was regulated by the amount of Et 3 N. This switchable N–N and N–C bond formation process features mild reaction conditions, simple execution, high chemoselectivity and broad substrate scope.
研究领域:
有机化学
·
合成化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2015
·
IF 3.564
Xue-Jie Wang,Jin-zong You,Feng Yu
The thermal decomposition of emtricitabine (FTC) was measured with thermogravimetry (TG), differential scanning calorimetry (DSC), and thermogravimetric analysis coupled with Fourier transform infrared spectroscopy (TG-FTIR). The infrared (IR) spectra, high performance liquid chromatography (HPLC), and liquid chromatography mass spectrometry (LC–MS) of FTC and the residues of its thermal decomposition at various temperatures were determined. The molecular bond orders were calculated with an ab initio method from the GAMESS program. The mechanism of thermal decomposition of FTC was discussed. The kinetic parameters of thermal decomposition such as activation energy E a and the pre-exponential factor A were obtained with the Ozawa method. The prospective lifetime of FTC was estimated with the Dakin equation. The results indicated that the thermal decomposition of FTC is a two-step process. In the thermal decomposition process, most of FTC decomposes directly to small molecules and insoluble substance due to the fracture of the N C bond of amide in the 5-fluorocytosine ring, a small amount of FTC decomposes to 5-fluorocytosine due to the fracture of the N -glycosidic bond, and a small amount of 5-fluorouracil and 2′,3′-dideoxy-5-fluoro-3′-thiauridine are generated due to the oxidation reaction. The initial decomposition temperature either nitrogen or air is 200 °C. For decomposition in nitrogen, the E a and A for the initial thermal decomposition are 142.4 kJ mol −1 and 2.09 × 10 13 min −1 , respectively. For decomposition in air, the corresponding E a and A are 140.7 kJ mol −1 and 1.62 × 10 13 min −1 , respectively. The thermal stability of FTC is very good under routine temperatures.
研究领域:
药物化学
·
物理化学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）