APPLIED SURFACE SCIENCE
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2023
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IF 6.7
Dehao Kong,Weirong Zhou,Jiayin Han,Yubing Gao,Yuan Gao,Liupeng Zhao,Peng Sun,Geyu Lu
Crystal facet engineering strategy is an effective way to regulate the exposed facets, which affect the ability of the surface to adsorb and react with gas molecules, ultimately enhancing the gas-sensing properties. In this work, Co 3 O 4 mesoporous nanosheets with dominant exposed {1 1 1} facets (Co 3 O 4 -60) or {1 1 2} facets (Co 3 O 4 -100) were synthesized by simply adjusting the condensation-reflux temperature. The sensing results toward toluene show that Co 3 O 4 -60 exhibited superior performance. According to the crystal structure analysis and work function calculations, the (1 1 1) facet composed of Co 2+ would adsorb more oxygen molecules, which have been proved by experimental characterization, facilitating the sensing efficiency. The results of X-ray photoelectron spectroscopy indicated that Co 3 O 4 -60 possesses a higher Co 2+ content and chemisorbed oxygen ratio (52.9%). Furthermore, Co 3 O 4 -60 has a high electrical conductivity and a minor apparent activation energy for toluene (38.75 kJ/mol). The gas sensor based on Co 3 O 4 -60 exhibited a response of 20.6 for 100 ppm toluene with rapid recovery and a detection limit of 1 ppm. Besides, other properties such as selectivity, repeatability, and humidity resistance were evaluated. This work evidences that crystal facet engineering is a practical approach to improving the gas-sensing properties of pure-phase Co 3 O 4 .
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高影响因子
FUEL
·
2022
·
IF 8.035
Li Wang,Wende Hu,Zhou Shang,Xiaoming Cao,Yun Guo,Jiayi Li,Qiyuan Gu,Ke Li,Xiaobo Li
Enhancement in oxidation performance of Co 3 O 4 -based catalysts can be achieved by regulating K, and the promotion effects were strongly depended on the amount and existing state of K. Only the surface Co substituted by optimum amount of K (CoK 2 with K/Co mole ratio of 1.56 × 10 -2 ), unexpectedly high activities could be achieved. The specific activity of CoK 2 were 20 and 2.7 times higher than that of Co 3 O 4 for CO oxidation and CH 4 combustion. However, the excess K in the form of carbonate or nitrate deactivated the active sites, so the performance against K amount behaved as a volcano curve. Based upon the electronic and structural modification of K, the electron density of Co and O simultaneously decreased which weakened CO adsorption strength and improved the C H bond activation. Since efficiency in various pollutants removal, CoK 2 could be considered as a promising candidate for noble metal catalysts.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2022
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IF 5.518
Xiaoqing Wang,Shiyao Jin,Yangdong Cui,Jing Zhang,Hongjing Lu,Yujie Ren,Guoxin Du,Junhe Ji,Jionghui Li,Chunhua Xiong
A series of Co 3 O 4 @C-N (N = 1, 2, 3) composite photocatalysts were prepared by simple agitation and pyrolysis for degradation of organic dyes. The hollow macroscopic spherical structure of Co 3 O 4 @C-2 was constructed by adjusting the pyrolysis time. Compared with pure Co 3 O 4 , the carbon composite Co 3 O 4 @C-2 significantly enhanced light absorption in the UV and visible range, improved the electron transport efficiency and prevented the necessary photoexcited electron-hole pair recombination. Hence, the photocatalytic degradation rate of methylene blue (MB, 20 mg/L) reached 100% in 120 min under UV–vis light irradiation . Under the coupling of Co 3 O 4 and graphitized carbon, Co 3 O 4 @C-2 obtained high structural stability, good reusability and low biotoxicity. Scavenging experiments and ESR test showed that •O 2- radical was the active species for MB removal. After six cycles of tests, the photocatalytic efficiency of Co 3 O 4 @C-2 remained at 90.42%. The macroscopic spherical structure Co 3 O 4 @C-2 effectively avoids the problem of dispersion and recovery of powder catalyst, which also paves a path for the designing of candidate commercial photocatalyst with high efficiency and low consumption.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2022
·
IF 6.371
Baohong Zhang,Lingxiao Gao,Haoze Bai,Yanhong Li,Binbin Jia,Xinyan Zhou,Anran Li,Lidong Li
Designing and optimizing electrode materials for supercapacitors (SCs) is generally considered to be an effective way to enhance their electrochemical performance. It is an attractive approach to obtaining high capacity electrodes by engineering the nanostructure and oxygen vacancies of electrodes. Herein, we developed an efficient and green strategy to facilitate one-dimensional (1D) Co 3 O 4 nanorods with abundant oxygen vacancies via Co nanorods oxidation by H 2 O 2 treatment, significantly promoting the electrochemical energy storage. The unique Co 3 O 4 NRs due to 1D nanostructure and oxygen vacancy, exhibit a high specific capacity of 627.4 mF cm −2 at a current density of 0.5 mA cm −2 and excellent rate capacity (57.8% capacitance retention at 10 mA cm −2 ). Furthermore, an asymmetric supercapacitor (ASC) constructed with the Co 3 O 4 nanorods as electrode materials shows a high energy density of 0.187 mWh cm −2 at a power density of 1.261 mW cm −2 . This nanostructure and vacancy engineering strategy put forward in this work is an inspiring example for the design of the next generation of SCs.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Xiaoya Fan,Chaoqun Ma,Donglin Zhao,Zhiqin Deng,Longcheng Zhang,Yan Wang,Yongsong Luo,Dongdong Zheng,Tingshuai Li,Jing Zhang,Shengjun Sun,Qipeng Lu,Xuping Sun
Electrochemical nitrate (NO 3 − ) reduction reaction (NO 3 RR) possesses two-pronged properties for sustainable ammonia (NH 3 ) synthesis and mitigating NO 3 − contamination in water. However, the sluggish kinetics for the direct eight-electron NO 3 − -to-NH 3 conversion makes a formidable challenge to develop efficient electrocatalysts. Herein, we report a heterostructure of Co 3 O 4 nanosheets decorated TiO 2 nanobelt array on titanium plate (Co 3 O 4 @TiO 2 /TP) as an efficient NO 3 RR electrocatalyst. Both experimental and density theory calculations reveal that the heterostructure of Co 3 O 4 @TiO 2 establishes a built-in electric field which can optimize the electron migration kinetics, as well as facilitate the adsorption and fixation of NO 3 − on the electrode surface, ensuring the selectivity to NH 3 . As expected, the designed Co 3 O 4 @TiO 2 /TP exhibits a remarkable Faradaic efficiency of 93.1 % and a remarkable NH 3 yield as high as 875 μmol h −1 cm −2 , superior to Co 3 O 4 /TP and TiO 2 /TP. Significantly, it also demonstrates strong electrochemical durability.
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高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Zijing Li,Zhaoxiaohan Shi,Limin Zhang,Hongjing Wu
Despite Co 3 O 4 has been widely applied in electromagnetic wave (EMW) absorbers, single Co 3 O 4 doesn't have excellent EMW absorbing performance. Modification of Co 3 O 4 with other metal ions addition is an effective way to improve its impedance matching and EMW attenuation. Herein, CuO/Cu 0.3 Co 2.7 O 4 /Co 3 O 4 and NiCo 2 O 4 /Co 3 O 4 composites have been obtained via a facile two-stage strategy, and the influence of Cu 2+ and Ni 2+ on the high-frequency and low-frequency EMW absorbing performance of the composites has been investigated as well. The electromagnetic parameters of samples are regulated by adding different metal ions to achieve optimum impedance matching. Dipole polarization and magnetic resonance are the main loss mechanisms. The composite with Cu 2+ and Ni 2+ additions exhibits the best EMW absorption with an effective absorption bandwidth (EAB) of 10.8–18.0 GHz for 2.1 mm thickness at high-frequency and 4.5–8.5 GHz for 4.9 mm thickness at low frequencies, respectively. This work offers an effective method for preparing composite materials with multicomponent broadband absorption of oxides.
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Journal of Physical Chemistry C
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2022
·
IF 4.177
Ting Yu,Xin Li,Bin Chen,Yanxing Yang,Keng Xu,Yuan Liu,Wufei Gong,Cailei Yuan,Yong Yang
Crystal facet engineering and graphene modification are both effective means to improve the gas sensing performance of metal oxide semiconductors (MOSs) currently. However, research on the crystal facet effect and synergistic effect of graphene modification of p-type MOS sensors is relatively lacking. Here, p-type Co3O4 nanocrystals with controlled crystal facets ({112} and {100}) were in situ wrapped in the two-dimensional (2D) nanosheet network of graphene. It was found that bare {112} facets showed a significantly higher triethylamine sensing performance than {100} facets, implying a strong crystal facet effect. Interestingly, the triethylamine sensing performance of {112} facets was significantly improved after rGO modification, while the performance improvement of Co3O4 {100} was limited after rGO modification. Further study suggested that {112} facets contained more active Co3+ species and chemically adsorbed oxygen species than {100} facets, which promoted the adsorption of triethylamine and the subsequent sensing reaction. In addition, the strong electronic interaction between Co3O4 {112} crystal facets and rGO promoted efficient charge exchange through the heterogeneous interface. This work provides a new way to improve the gas sensing performance of Co3O4 through the synergistic effect of crystal facet engineering and graphene modification.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2022
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IF 24.319
Chunlin Chen,Zhenqiang Zhou,Jing Liu,Bin Zhu,Hualei Hu,Yong Yang,Guoxin Chen,Minrui Gao,Jian Zhang
Substituting overall water splitting with simultaneous biomass upgrading and H 2 evolution has drawn tremendous attention due to the lower energy barrier and higher safety. Developing a cheap, efficient, and durable electrocatalyst with dual function is crucial to this novel coupling system. Herein, we propose the in-situ electrochemical tuning nonporous CoS x to hydrangea-like Co 3 O 4 as a highly effective versatile electrocatalyst for the first time. Due to the defective structures and abundant electroactive sites, the Co 3 O 4 catalyst achieved a complete conversion of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) with 93.2% yield and 92.9% faradaic efficiency (FE), as well as a pure hydrogen evolution with 99.8% FE. Interestingly, it harvested a better performance with 95.8% FDCA yield for electro-oxidation of the more stable 2,5-bis(hydroxymethyl)furan (BHMF). Finally, a solar-driven integration reaction was constructed for the first time using the photovoltaic electrocatalysis (PVEC) of BHMF for the efficient and sustainable production of FDCA and H 2 .
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
·
2022
·
IF 9.221
Xiangrui Bu,Fa Ma,Qiang Wu,Haiyang Wu,Yubin Yuan,Long Hu,Chuanyu Han,Xiaoli Wang,Weihua Liu,Xin Li
Volatile organic compounds (VOCs) detection in ultra-low concentrations is highly demanded in industry and daily life. Ethanol is one of the most encountered VOCs. Through calcining the precursor of metal-organic frameworks (MOFs), which are in situ grown on 2D Ti 3 C 2 T x sheets, Co 3 O 4 /Ti 3 C 2 T x nanocomposites with the mesoporous structure were synthesized for ethanol sensing. The results showed that the Co 3 O 4 /Ti 3 C 2 T x sensor has an ultra-high response ( (190 towards 50 ppm ethanol), fast response/recovery speed (50 s/45 s to 50 ppm ethanol), a low detection limit (<1 ppm), ideal selectivity and long-term stability. Compared to the pure Co 3 O 4 and Ti 3 C 2 T x sensors, the Co 3 O 4 /Ti 3 C 2 T x nanocomposites sensor significantly improves ethanol-sensing performance. Within the nanocomposites, the 2D Ti 3 C 2 T x nanosheet acts as a favorable platform for the uniform nucleation and growth of Co 3 O 4 , while the mesoporous Co 3 O 4 can provide more adsorption sites for gas sensing. In addition, the formation of hybrid heterojunction is also an essential factor for enhanced sensing behaviors. This work provides a new avenue to develop nanocomposites based on metal oxide and 2D materials for VOCs sensing.
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CATALYSIS LETTERS
·
2022
·Vol. 153
·期 4
·965-977
·
IF 2.936
Zhang Tong,Zhao HuaHua,Yang Jian,Zhao Jun,Yan Liang,Chou Lingjun,Song Huanling
Selective hydrogenation of crotonaldehyde to crotyl alcohol over PDA (polydopamine) modified Co 3 O 4 supported Pt catalysts was investigated in liquid phase. The catalysts which contain PDA and Co 3 O 4 lead to the formation of two kinds of interfaces: Pt-PDA and Pt-Co 3 O 4 , which greatly improves the performance in the hydrogenation of crotonaldehyde. TEM results reveal that the Pt nanoparticles of Pt/Co 3 O 4 @PDA have a smaller size and better dispersion than Pt/Co 3 O 4 . XPS, FT-IR and CO-DRIFTs results indicate that the addition of PDA decreases the electron density of Pt which is favor to the hydrogenation of C=O in crotonaldehyde. The characterization results demonstrate that the interaction between Pt and PDA creates new active interfacial sites and the synergy of Pt-PDA and Pt-Co 3 O 4 is responsible for the excellent performance. Graphical Abstract
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高影响因子
ELECTROCHIMICA ACTA
·
2022
·
IF 7.336
Lei Ding,Tianyue Huang,Dawei Zhang,Pan Qi,Lihao Zhang,Cong Lin,Hao Luo
Rational design and synthesis of high-performance bifunctional oxygen electrocatalysts with increased effective active sites and facilitated mass/electron transfer are in demand for the lithium-oxygen batteries (LOBs) to overcome the sluggish oxygen reduction/evolution kinetics. Herein, a simple yet effective strategy is proposed by annealing the Prussian blue analog (PBA) precursor under altered calcination conditions to achieve the efficient nano-heterojunction catalysts with optimized active sites. As a result, the obtained porous Co 3 O 4 /Co nano-heterostructures embedded in N-doped graphitized carbon matrix (Co 3 O 4 /Co@NC) exhibit outstanding electrochemical performance with a high specific capacity of 22,156 mA h g −1 at the current density of 100 mA g −1 and excellent stability, obviously superior to the LOBs based on the other single-component catalysts. Systematic investigations suggest that the enhanced electrochemical performance is ascribed to the Co 3 O 4 /Co nano-heterostructure interface and the N-doped porous carbon matrix. This study presents a simple and effective approach for boosting the PBA-derived catalysts with efficient reactivity for various catalytic applications.
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Nanomaterials
·
2022
·Vol. 12
·期 10
·1695
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IF 5.719
Haodong Wen,Wenning Zhao,Xiuxun Han
Layered perovskite-type semiconductor La2Ti2O7has attracted lots of attention in photocatalytic hydrogen evolution, due to the suitable energy band position for water splitting, high specific surface area, and excellent physicochemical stability. However, the narrow light absorption range and the low separation efficiency of photogenerated carriers limit its photocatalytic activity. Herein, plate-like La2Ti2O7with uniform crystal morphology was synthesized in molten NaCl salt. A p-n heterojunction was then constructed through the in situ hydrothermal growth of p-type Co3O4nanoparticles on the surface of n-type plate-like La2Ti2O7. The effects of Co3O4loading on photocatalytic hydrogen evolution performance were investigated in detail. The results demonstrate that composite Co3O4/La2Ti2O7possesses much better photocatalytic activity than the pure component. The composite photocatalyst with 1 wt% Co3O4exhibits the highest hydrogen evolution rate of 79.73 μmol·g−1·h−1and a good cycling stability. The photoelectrochemistry characterizations illustrate that the improvement of photocatalytic activity is mainly attributed to both the enhanced light absorption from the Co3O4ornament and the rapid separation of photogenerated electron-hole pairs driven by the built-in electric field close to the p-n heterojunction. The results may provide further insights into the design of high-efficiency La2Ti2O7-based heterojunctions for photocatalytic hydrogen evolution.Keywords:photocatalysis;hydrogen evolution;p-n heterojunction;La2Ti2O7;Co3O4
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