COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
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IF 5.518
Chengcheng Qi,Chongchao Zhang,Ziyin Yang
Defect engineering was considered as an effective strategy to regulate electrocatalytic activities of transition metal oxides . However, there are seldom reports about metal defects in electrochemical sensing. In this work, Co-defected Co 3 O 4 was synthesized via thermal treatment of glycerolatocobalt (CoGly) precursor for constructing a novel electrochemical nonenzymatic glucose sensor. The obtained nanomaterials were characterized by transmission electron microscopy (TEM), powder X-ray diffractometry (XRD), Raman spectra , X-ray photoelectron spectroscopy (XPS) and electrochemical techniques . The presence of Co defects regulated electronic structure of Co 3 O 4 , which not only speeds up electron transfer rate but also exposes more high-valent Co sites, thus improving electrocatalytic activities. Under optimized conditions, Co-defected Co 3 O 4 electrode exhibited excellent performance for glucose analysis with a wide linear range of 0.2 µM to 0.5 mM, a low detection limit of 0.16 µM. Importantly, an ultrahigh sensitivity of 2595.7 µA·mM −1 ·cm −2 was also obtained, which was about 10 times higher than that of conventional Co 3 O 4 . Therefore, engineering Co 3 O 4 with Co defects is an effective strategy to tailor electrocatalytic activity, which sheds light on the potential applications of metal defects in the field of electrochemical nonenzymatic sensing.
研究领域:
材料科学
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电化学传感
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生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Chemistry
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2024
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IF 14
Haoyu Zhan,Baixue Cheng,Yankun Lu,Danning Xing,Xingshuai Lv,Huining Huang,Thomas Frauenheim,Tao Wang,Peng Zhou
Co 3 O 4 possesses both direct and indirect oxidation effects and is considered as a promising catalyst for the oxidation of 5-hydroxymethylfurfural (HMF). However, the enrichment and activation effects of Co 3 O 4 on OH − and HMF are weak, which limits its further application. Metal defect engineering can regulate the electronic structure, optimize the adsorption of intermediates, and improve the catalytic activity by breaking the symmetry of the material, which is rarely involved in the upgrading of biomass. In this work, we prepare Co 3 O 4 with metal defects and load the precious metal platinum at the defect sites (Pt-Vco). The results of in-situ characterizations, electrochemical measurements, and theoretical calculations indicate that the reduction of Co–Co coordination number and the formation of Pt–Co bond induce the decrease of electron filling in the antibonding orbitals of Co element. The resulting upward shift of the d -band center of Co combined with the characteristic adsorption of Pt species synergically enhances the enrichment and activation of organic molecules and OH − species, thus exhibiting excellent HMF oxidation activity (including a lower onset potential (1.14 V) and 19 times higher current density than pure Co 3 O 4 at 1.35 V). In summary, this work explores the adsorption enhancement mechanism of metal defect sites modified by precious metal in detail, provides a new option for improving the HMF oxidation activity of cobalt-based materials, broadens the application field of metal defect based materials, and gives an innovative guidance for the functional utilization of metal defect sites in biomass conversion.
研究领域:
材料科学
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化学工程
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生物质转化
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2023
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IF 15.1
Lixia Wang,Jia Huang,Zhiyang Huang,Huatong Li,Tayirjan Taylor Isimjan,Xiulin Yang
Metallic defects can improve catalysts' intrinsic activity by regulating its electronic structure and enhancing conductivity. However, the impact of these defects on the kinetics of the oxygen evolution reaction (OER) has not been extensively studied. Here, a V/P codoped nanoflower-like CoS 2 catalyst with rich Co defects on carbon cloth (V,P-CoS 2 /CC) is fabricated by feasible directional construction. The V,P-CoS 2 /CC validates extraordinary OER performance with overpotentials of 227/300 mV at 10/100 mA cm −2 and robust long-term stability. The enhanced single-electron spin resonance signal and higher lifetime strength indicate an increased number of surface Co defects induced by V/P codoping. Density functional theory (DFT) calculations verify that Co defects induced by V/P codoping of the surface reconstituted V-CoOOH/CoS 2 catalyst can optimize the adsorption/desorption energy of oxygen-containing intermediates to accelerate OER process. Besides, the nanoflower-like morphology with large electrochemical active surface area and good hydrophilicity facilitates electrolyte diffusion/gas emission, thereby synergistically elevating OER performance.
研究领域:
材料科学
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电化学
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理论计算
✓ 已验证
产品关联
DOI
高影响因子
ACS Catalysis
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2022
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IF 13.7
Jingxuan Zheng,Xiangfeng Peng,Zhao Xu,Junbo Gong,Zhao Wang
Defect engineering is a promising method to solve the inherent low conductivity and limited number of reactive sites of metal oxides as electrocatalysts. High formation energy makes it challenging to controllably produce metal defects in metal oxides. In this study, abundant Co defects were preferentially produced on spinel NiCo2O4 by tuning the M–O bond length and interfering with ionization of the crystal surface. Theoretical calculations and experiments proved that Al doping elongated the Co–O bond and promoted ionization of Co under plasma treatment. Furthermore, Co ions in the crystal lattice were selectively taken away by adding NaOH to combine with surface-ionized metal ions, which facilitated the formation of cobalt defects. The Co defects induced electron delocalization, which effectively increased the carrier concentration and intrinsic conductivity of the catalysts, thereby enhancing the intrinsic OER catalytic activity of NiCo2O4.
研究领域:
材料科学
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电化学
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催化
✓ 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）