CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Xin Liu,Mengmeng Fan,Xuguang Zhu,Zengguo Tian,Xin-Jian Li,Hongzhang Song
Bi 2 Sr 2 Co 2 O y with excellent thermoelectric properties has received extensive attention from scientific researchers. In this study, Bi 2 Sr 2 Co 2 O y ceramic samples were prepared using the solid-phase sintering method. By Ag + substitution for Bi 3+ , the hole concentration and electrical conductivity were optimised. On this basis, nano-SiC particles were introduced to increase grain boundaries, improve phonon scattering, reduce the mean free path of phonons, and reduce the lattice thermal conductivity . A sample with a nominal composition of Bi 1.8 Ag 0.2 Sr 2 Co 2 O y + 0.025 wt% SiC had a maximum ZT value of 0.35 at 923 K, which was approximately 67 % higher than the ZT value of pure Bi 2 Sr 2 Co 2 O y . These results confirmed that under the combined action of Ag substitution and SiC doping, the thermoelectric performance of Bi 2 Sr 2 Co 2 O y was significantly improved.
研究领域:
材料科学
·
热电材料研究
✓ 已验证
产品关联
DOI
高影响因子
GREEN CHEMISTRY
·
2022
·Vol. 24
·期 22
·8840-8852
·
IF 11.034
Zongyang Liu,Yuan Tan,Jie Li,Xiuli Li,Yan Xiao,Juan Su,Xingkun Chen,Botao Qiao,Yunjie Ding
Aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) is a promising alternative route to produce renewable biodegradable plastics, which has stimulated intense interest in recent years. Supported gold catalysts have shown great potential for this reaction, but the selectivity and stability need to be improved. In addition, the requirement for base additives makes the process less effective and sustainable. Herein, highly active and selective Au–Ag bimetallic nanoclusters supported on MgAl-hydrotalcite (HT) were developed for HMF oxidation to FDCA under base-free reaction conditions using molecular oxygen as the oxidant. The presence of small amounts of Ag (0.034–0.065 wt%) in Au25 clusters greatly enhanced the catalytic reaction rates and selectivity for HMF tandem oxidative steps, leading to both high conversion of HMF (>97%) and high yield of FDCA (>95%). Besides, the catalyst stability was also enhanced by the addition of Ag. The characterization results suggested that the substitution of Ag atoms modified the electronic structure of Au while likely maintaining the primary geometry. Thus, a significant synergistic effect could be observed over trace Ag modified Au–Ag bimetallic nanoclusters. The present work provides new insight into the alloying effect, and helps understand highly efficient Au-based catalysts for aerobic oxidation of biomass derived molecules under base-free conditions.
研究领域:
催化化学
·
可再生资源化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Lijuan Fu,Junsheng Yu,Jinsong Wang,Fan Xie,Shun Yao,Yongsong Zhang,Jiang Cheng,Lu Li
CuSbS 2 has been considered as a promising photovoltaic absorber material, due to its earth abundant and environmentally friendly constituents. However, the electron affinity and similar radius of cations bring heavy atomic disorders in CuSbS 2 film, limiting its photovoltaic performance. Herein, we report an efficient way to reduce disorders by introducing Ag atom into CuSbS 2 crystal structure. The crystal structure and chemical analysis confirm that Ag occupies the Cu position in the as-prepared films by the spray pyrolysis. The absorption spectra combined with photoluminescence measurement indicate that Ag-substituted CuSbS 2 films have fewer recombination centers. The density functional theory calculation result reveals that Ag-substituted CuSbS 2 has a more stable crystal structure, and the formation energy of the primary point defects obviously increases. Therefore, Ag-substituted CuSbS 2 photovoltaic device shows asignificantly improved power conversion efficiency from 0.73% to 2.48%.
研究领域:
材料科学
·
光伏技术
·
理论计算
✓ 已验证
产品关联
DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2024
·Vol. 130
·期 3
·1-11
·
IF 2.5
Hu Jiaming,Han Xiuxun,Zhu Wuzhi,Wu Fangfang,Tan Xiaohui
Incorporating substitutional elements from groups I, II and IV is an important approach to improve the quality of kesterite thin films. Among the elements, Ag and Ge are most effective in promoting the performance of Cu 2 ZnSn(S,Se) 4 solar cells. Although several theoretical and experimental studies have been conducted on the Ag/Ge-alloyed kesterite, there are significant differences in the reported morphological characteristics, photovoltaic performance and even the optimal Ag/Ge substitution ratio due to different preparation processes utilized, which leads to difficulties in comparing the Ag-incorporated and Ge-incorporated kesterite solar cells. Currently, there is little literature on the comparative study concerned. Herein, we fabricated Ag-alloyed and Ge-alloyed kesterite solar cells based on the same solution method and process conditions, and laterally compared the effects of Ag substitution and Ge substitution on the phase compositions, morphologies, optical bandgaps, minority carrier lifetime and device performance of kesterite Cu 2 ZnSn(S,Se) 4 thin films.
研究领域:
材料科学
·
光伏技术
·
薄膜技术
·
固体物理
·
半导体器件
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）