Nanoporous IrO2 catalyst with enhanced activity and durability for water oxidation owing to its micro/mesoporous structure

Nanoscale ◽  
2017 ◽  
Vol 9 (27) ◽  
pp. 9291-9298 ◽  
Author(s):  
Guoqiang Li ◽  
Songtao Li ◽  
Meiling Xiao ◽  
Junjie Ge ◽  
Changpeng Liu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Oxygen Evolution ◽  
Specific Surface Area ◽  
Oxygen Evolution Reaction ◽  
Water Oxidation ◽  
Mesoporous Structure ◽  
Electrocatalytic Performance ◽  
Enhanced Activity ◽  
Iro2 Catalyst

Micro/mesoporous IrO2 catalyst with an ultrahigh specific surface area of 363.3 m2 g−1 shows excellent electrocatalytic performance for the oxygen evolution reaction.

Solvent dispersion triggered the formation of NiFe-gel as an efficient electrocatalyst for enhancing the oxygen evolution reaction

2020 ◽  
Vol 56 (56) ◽  
pp. 7781-7784
Author(s):  
Hongkai Wang ◽  
Weihuang Zhu ◽  
Qi Xue ◽  
Changhao Wang ◽  
Kaiqiang Liu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Oxygen Evolution ◽  
Specific Surface Area ◽  
Oxygen Evolution Reaction ◽  
Alkaline Electrolyte

The solvent dispersion triggered gelation for a Ni2.0Fe-gel catalyst has a specific surface area of 216.9 m2 g−1, and its overpotential in an alkaline electrolyte can reach a lower value with 245 mV at 10 mA cm−2 than commercial metal RuO2.

In-situ controlled synthesis of NiFe MOF materials with excellent electrocatalytic performances for water splitting

2021 ◽  
Vol 14 (02) ◽  
pp. 2151011
Author(s):  
Jingwen Jia ◽  
Longfu Wei ◽  
Ziting Guo ◽  
Fang Li ◽  
Changlin Yu ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Water Splitting ◽  
Specific Surface Area ◽  
High Performance ◽  
Alkaline Condition ◽  
High Porosity ◽  
Large Specific Surface Area ◽  
Electrocatalytic Performance

Metal–organic frameworks (MOFs) are the electrocatalytic materials with large specific surface area, high porosity, controllable structure and monodisperse active center, which is a promising candidate for the application of electrochemical energy conversion. However, the electrocatalytic performance of pure MOFs is seriously limited its poor conductivity and stability. In this work, high-performance electrocatalyst was fabricated through combining NiFe/MOF on nickel foam (NF) via in-situ growth strategy. Through rational control of the time and ratio in reaction precursors, we realized the effective manipulation of the growth behavior, and further investigated the electrocatalytic performance in water splitting. The catalyst presented excellent electrocatalytic performance for water splitting, with low overpotential of 260 mV in alkaline condition at a current density of 50 mA[Formula: see text], which is benefited from the large specific surface area and active sites. This study demonstrates that the rational design of NiFe MOF/NF plays a significant role in high-performance electrocatalyst.

Preparation of Nitrogen-Deficient Graphitic Carbon Nitride with a Large Specific Surface Area by Melt Pretreatment and Its Photocatalytic Performance

NANO ◽  
2020 ◽  
Vol 15 (06) ◽  
pp. 2050079
Author(s):  
Xuelei Li ◽  
Jinfeng Bai ◽  
Jiaqi Li ◽  
Chao Li ◽  
Junru Zhang ◽  
...  
Keyword(s):  
Visible Light ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Carbon Nitride ◽  
Mesoporous Structure ◽  
Graphitic Carbon ◽  
Graphitic Carbon Nitride ◽  
Large Specific Surface Area ◽  
X Ray

In this study, nitrogen-deficient graphitic carbon nitride (M-LS-g-C3N4) with a mesoporous structure and a large specific surface area was obtained by calcination after melt pretreatment using urea as a precursor. X-ray diffraction (XRD), transmission electron microscopy (TEM), N2 adsorption, X-ray photoelectron spectroscopy (XPS), UV-Vis, ESR and photoluminescence (PL) were used to characterize the structure, morphology and optical performance of the samples. The TEM results showed the formation of a mesoporous structure on the 0.1[Formula: see text]M-LS-g-C3N4 surface. The porous structure led to an increase in the specific surface area from 41.5[Formula: see text]m2/g to 124.3[Formula: see text]m2/g. The UV-Vis results showed that nitrogen vacancies generated during the modification process reduced the band gap of g-C3N4 and improved the visible light absorption. The PL spectra showed that the nitrogen defects promoted the separation of photogenerated electron–hole pairs. In the visible light degradation of methyl orange (MO), the reaction rate constant of 0.1[Formula: see text]M-LS-g-C3N4 reached 0.0086[Formula: see text][Formula: see text], which was 5.05 times that of pure g-C3N4. Superoxide radicals and photogenerated holes were found to be the main active species in the reaction system. This study provides an efficient, green and convenient means of preparing graphitic carbon nitride with a large specific surface area.

scholarly journals Enhancement in Graphitization of Ordered Mesoporous Carbon by Assistance of Soybean Oil Surfactant

2020 ◽  
Vol 36 (3) ◽  
Author(s):  
Le Thi Thu Hang ◽  
Hoang Thi Bich Thuy
Keyword(s):  
Soybean Oil ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Pore Volume ◽  
Mesoporous Carbon ◽  
Mesoporous Structure ◽  
Ordered Mesoporous Carbon ◽  
Graphitization Degree ◽  
Ordered Mesoporous

In this work, highly ordered mesoporous graphitic carbon (G-CMK3) has been prepared successfully by a nano-casting method using sucrose as carbon source, mesoporous silica as hard template, and soybean oil as surfactant. In the absence of soybean oil surfactant, the synthesized ordered mesoporous carbon material, CMK-3, revealed a low graphitization degree with a specific surface area of 1049.1 m2/g and a high pore volume of 1.172 cm3/g.  However, with the assistance of soybean oil surfactant, the graphitization degree was improved significantly, which was confirmed by the decrease in the ID/IG intensity ratio of the D (disordered or amorphous structure) and G (graphitic structure) peaks from 0.98 to 0.83. After the synthesis in the presence of soybean oil, G-CMK3 carbon maintained the integrity of the mesoporous structure albeit with a slight decrease in its specific surface area (845.2 m2/g) as well as pore volume (0.858 cm3/g).

Synthesis and Structural Characterization of SiO2-Al2O3 Xerogels

2007 ◽  
Vol 336-338 ◽  
pp. 2286-2289
Author(s):  
Fei He ◽  
Xiao Dong He ◽  
Yao Li
Keyword(s):  
Structural Change ◽  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Mesoporous Structure ◽  
Supercritical Drying ◽  
High Specific Surface Area ◽  
Molar Ratio

Low-density xSiO2-(1-x)Al2O3 xerogels with x=0.9, 0.8, 0.7, 0.6 (mole fractions) were prepared by sol-gel and non-supercritical drying. Silica alkogels, which were the framework of binary composite materials, formed from tetraethyl orthosilicate (TEOS) by hydrolytic condensation with a molar ratio of TEOS: H2O: alcohol: hydrochloric acid: ammonia =1: 4: 10: 7.5×10-4: 0.0375. Aluminum hydroxide derived from Al(NO3)3·9H2O and NH4OH acting in the alcohol solution under the condition of catalyst. After filtrating and washing, the precipitation was mixed into silica sols to form SiO2-Al2O3 mixed oxide gels with different silicon and aluminum molar ratio. The structural change and crystallization of the binary xerogels were investigated after heat treatment at 600 for 2 h by the means of X-ray diffraction. Nitrogen adsorption experiment was performed to estimate specific surface area, porous volume and pore size distribution. The structural change of xerogels was observed by FT-IR spectroscopy. The resulting mixed xerogels possess of mesoporous structure which is characteristic of cylindrical pores, high specific surface area of 596-863 m2/g and a relatively narrow pore distribution of 2.8-30 nm. Al2O3 is introduced into the SiO2 phase and some of Al-O-Si bonds form.

Synthesis and Characterization of RuO2 Anode Materials with Large Surface Areas for Oxygen Evolution Reaction

2012 ◽  
Vol 15 (4) ◽  
pp. 271-276 ◽  
Author(s):  
Yang Zhang ◽  
Lixia Yue ◽  
Ke Teng ◽  
Shiyong Yuan ◽  
Hongchao Ma
Keyword(s):  
Porous Structure ◽  
Electrochemical Properties ◽  
Surface Area ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Mesoporous Structure ◽  
Large Surface Area ◽  
Precipitation Method ◽  
Surface Areas ◽  
Lower Temperature

A novel olivary or petal-like RuO2 material with large surface area was successfully synthesized by surfactant-assisted homogeneous precipitation method using urea and dodecyl sulfate as the source reagent. The surface morphology, structural, and electrochemical properties of as-synthesized RuO2 materials were characterized by x-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), Cyclic voltammetry (CV), N2 adsorption–desorption isotherms and polarization curve for oxygen evolution reaction (OER). It was found that the morphology and crystalline structures and electrochemical properties of as-synthesized RuO2 materials were strongly dependent on the calcining temperature. The ruthenium-surfactant mesophase with mesoporous structure transformed from network to regular olivary or petal-like RuO2 materials and remaining partial mesoporous character after calcination at lower temperature (i.e., 300 and 400 °C). However, the mesophase transformed into RuO2 agglomeration consisted of nanosized particles after calcination at 650 °C, which may be attributed to complete deorganization and porous structure collapse of RuO2 materials. In addition, the as-synthesized RuO2 materials showed higher specific surface area and better electrochemical activities for oxygen evolution reaction compared with the RuO2 prepared without surfactant. The electrochemical activity of as-synthesized RuO2 material calcined at 400 °C is about 3 times than that of RuO2 prepared without surfactant for oxygen evolution reaction. This can be attributed to the porous structure and large surface area of as-synthesized RuO2 materials.

scholarly journals Efficient Sunlight-Induced Methylene Blue Removal over One-Dimensional Mesoporous Monoclinic BiVO4Nanorods

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Linrui Hou ◽  
Long Yang ◽  
Jiaoyang Li ◽  
Jie Tan ◽  
Changzhou Yuan
Keyword(s):  
Methylene Blue ◽  
Specific Surface ◽  
Band Gap ◽  
Surface Area ◽  
Specific Surface Area ◽  
Mesoporous Structure ◽  
High Specific Surface Area ◽  
One Dimensional ◽  
Light Region ◽  
Degussa P25

Sunlight-driven mesoporous BiVO4nanorods with monoclinic structure have been successfully synthesizedviaa simple hydrothermal method. The as-prepared one-dimensional BiVO4nanorods exhibited high specific surface area due to their unique mesoporous structure. The mesoporous BiVO4nanorods possessed strong photoabsorption properties in the visible light region as well as the ultravisible region, and the band gap was estimated to beca.2.18 eV. The photocatalytic activities were evaluated by decolorization of methylene blue under sunlight irradiation. Photocatalytic tests demonstrated that the decolorization rate of as-prepared mesoporous BiVO4nanorods was even up to 98.8% in 180 min, much better than that prepared by solid-state reaction (23.1%) and the commercial TiO2(Degussa P25) (14.2%) under the same conditions, due to their higher specific surface area and appropriate band gap. Moreover, the unique BiVO4nanorods exhibit high stability after five photocatalytic degradation recycles.

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