scholarly journals Increasing Silicon Concentration and Doping Heteroatom to Successfully Realize High HER Catalytic Activity in 2D Metal-Free BSin (n = 1-4) Structures: A First-Principles Study

2021 ◽  
Author(s):  
Cuimei Li ◽  
Guangtao Yu ◽  
Ying Li ◽  
wei Chen
Keyword(s):  
Catalytic Activity ◽  
First Principles ◽  
Active Sites ◽  
Low Cost ◽  
Atomic Ratio ◽  
Two Dimensional ◽  
Metal Free ◽  
Catalytic Activities ◽  
High Efficient ◽  
New Strategies

Abstract Under the DFT calculations, the graphene-like two-dimensional (2D) BSin (n = 1-4) nanostructures are stable in terms of energy, kinetics and thermal aspects, and can possess metallic conductivity, which are advantageous to their catalytic activities for hydrogen evolution reaction (HER). Our computed results reveal that they can uniformly exhibit high HER catalytic activity. With increasing the Si/B atomic ratio, higher HER activity can be achieved, due to the change from weak aromaticity to strong anti-aromaticity for the correlative BxSiy six-membered rings. Moreover, by doping P, S, Ge and C atoms with the different electronegativity, the HER activity of the studied systems can be further improved because the electron transfer induced by these dopants can effectively activates the relevant B and Si atoms. In addition, in view of more active sites, increasing the Si concentration can also generally increase the HER activity of doped systems. For all BSin systems studied, the Si-Si bridge sites or Si-sites can uniformly serve as the most active sites. This study not only represents the first application of 2D metal-free BSin in HER catalysis, but also provides new strategies for designing high-efficient and low-cost HER electrocatalysts based on Si/B or even other Si-containing materials.

Template-directed approach to two-dimensional molybdenum phosphide–carbon nanocomposites with high catalytic activities in the hydrogen evolution reaction

2016 ◽  
Vol 40 (7) ◽  
pp. 6015-6021 ◽  
Author(s):  
Zhaoquan Yao ◽  
Yuezeng Su ◽  
Chenbao Lu ◽  
Chongqing Yang ◽  
Zhixiao Xu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Catalytic Activity ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
High Catalytic Activity ◽  
Two Dimensional ◽  
Carbon Nanocomposites ◽  
Carbon Nanosheets ◽  
Catalytic Activities ◽  
Molybdenum Phosphide

MoP-embedded 2D N-doped porous carbon nanosheets, with excellent electrical conductivity and abundant active sites, achieved high catalytic activity in the HER.

Two-dimensional penta-SiAs2: a potential metal-free photocatalyst for overall water splitting

2020 ◽  
Vol 8 (34) ◽  
pp. 11980-11987
Author(s):  
Kai Zheng ◽  
Heping Cui ◽  
Houcai Luo ◽  
Jiabing Yu ◽  
Shaogang Wang ◽  
...  
Keyword(s):  
Water Splitting ◽  
First Principles ◽  
Photocatalytic Performance ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Metal Free ◽  
Overall Water Splitting

We thoroughly investigated the photocatalytic performance of novel 2D penta-SiAs2 as an efficient photocatalyst based on first-principles calculations.

Fabrication of a mesoporous Ba0.5Sr0.5Co0.8Fe0.2O3−δ perovskite as a low-cost and efficient catalyst for oxygen reduction

2017 ◽  
Vol 46 (40) ◽  
pp. 13903-13911 ◽  
Author(s):  
Xiangzhi Cui ◽  
Ryan O'Hayre ◽  
Svitlana Pylypenko ◽  
Linlin Zhang ◽  
Liming Zeng ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Precious Metal ◽  
Oxygen Vacancies ◽  
Low Cost ◽  
Cathode Catalyst ◽  
Methanol Tolerance ◽  
Efficient Catalyst ◽  
Metal Free ◽  
Redox Couples ◽  
Catalytic Stability

The redox couples Co4+/Co3+ and Fe3+/Fe2+, and oxygen vacancies in mesoporous Ba0.5Sr0.5Co0.8Fe0.2O3−δ endow the precious metal-free cathode catalyst with high ORR catalytic activity, and more importantly excellent methanol tolerance and electro-catalytic stability.

Iron incorporation affecting the structure and boosting catalytic activity of β-Co(OH)2: exploring the reaction mechanism of ultrathin two-dimensional carbon-free Fe3O4-decorated β-Co(OH)2nanosheets as efficient oxygen evolution electrocatalysts

2017 ◽  
Vol 5 (15) ◽  
pp. 6849-6859 ◽  
Author(s):  
Fengzhan Sun ◽  
Linbo Li ◽  
Guo Wang ◽  
Yuqing Lin
Keyword(s):  
Catalytic Activity ◽  
Reaction Mechanism ◽  
Oxygen Evolution ◽  
First Principles ◽  
Oxygen Evolution Reaction ◽  
First Principles Calculation ◽  
Two Dimensional ◽  
Iron Incorporation

Ultrathin two-dimensional Fe3O4-decorated β-Co(OH)2nanosheets are synthesized for oxygen evolution reaction and reaction mechanism is explored by first principles calculation.

Carbon Dioxide Hydrogenation to Methanol over Cu/ZnO-SBA-15 Catalyst: Effect of Metal Loading

2017 ◽  
Vol 380 ◽  
pp. 151-160 ◽  
Author(s):  
Sara Faiz Hanna Tasfy ◽  
Noor Asmawati Mohd Zabidi ◽  
Maizatul Shima Shaharun ◽  
Duvvria Subbarao ◽  
Ahmed Elbagir
Keyword(s):  
Catalytic Activity ◽  
Carbon Source ◽  
Active Sites ◽  
Low Cost ◽  
Fixed Bed ◽  
Textural Properties ◽  
Catalytic Performance ◽  
Hydrogenation Reaction ◽  
Supported Metal Catalysts ◽  
Metal Loading

Utilization of CO2 as a carbon source to produce valuable chemicals is one of the important ways to reduce the global warming caused by increasing CO2 in the atmosphere. Supported metal catalysts are crucial to produce clean and renewable fuels and chemicals from the stable CO2 molecules. The catalytic conversion of CO2 into methanol is recently under increased scrutiny as an opportunity to be used as a low-cost carbon source. Therefore, a series of the bimetallic Cu/ZnO-based catalyst supported by SBA-15 were synthesized via an impregnation technique with different total metal loading and tested in the catalytic hydrogenation of CO2 to methanol. The morphological and textural properties of the synthesized catalysts were determined by transmission electron microscopy (TEM), temperature programmed desorption, reduction, oxidation and pulse chemisorption (TPDRO), and N2-adsorption. The CO2 hydrogenation reaction was performed in a microactivity fixed-bed system at 250oC, 2.25 MPa, and H2/CO2 ratio of 3. Experimental results showed that the catalytic structure and performance were strongly affected by the loading of the active site. Where, the catalytic activity, the methanol selectivity as well as the space-time yield increased with increasing the metal loading until it reaches the maximum values at a metal loading of 15 wt% while further addition of metal inhibits the catalytic performance. The higher catalytic activity of 14% and methanol selectivity of 92% was obtained over a Cu/ZnO-SBA-15 catalyst with a total bimetallic loading of 15 wt%. The excellent performance of 15 wt% Cu/ZnO-SBA-15 catalyst is attributed to the presence of well dispersed active sites with small particle size, higher Cu surface area, and lower catalytic reducibility.

Effects of substituted metal-free porphyrins in apo-horseradish peroxidase

2007 ◽  
Vol 11 (12) ◽  
pp. 836-845
Author(s):  
A. Molaei Rad ◽  
A. Akbar Moosavi-Movahedi ◽  
Hedayatollah Ghourchian ◽  
Nasser Safari ◽  
Jun Hong ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Horseradish Peroxidase ◽  
Fluorescence Emission ◽  
Potassium Phosphate ◽  
Phosphate Solution ◽  
Metal Free ◽  
Catalytic Activities ◽  
Polar Environment ◽  
Free Metal ◽  
Steric Hindrances

The peroxidase-like catalytic activities of some synthetic porphyrins following substitution in apo-horseradish peroxidase (apo-HRP) were studied by UV-vis and fluorescence spectrophotometries in buffer potassium phosphate solution at pH 7. The insertion of these synthetic porphyrins in apo-HRP is very difficult, due to steric hindrances between coordinated metals in porphyrins and the side-chains of amino acids in native protein. However, because of planar coordination following insertion in an active site of apo-HRP tetrapyridylporphyrin(TPyP), a metal-free porphyrin, adsorbs free metal ions from the environment and shows higher peroxidase-like catalytic activity than other new synthetic porphyrins. The results indicate that the metal-free porphyrins with optimum Reinheitzahl (RZ) show higher catalytic activity relative to others. The fluorescence emission of TPyP only, and of apo-HRP-TPyP, displayed significantly different wavelengths for the maximum aromatic fluorescence intensity. The λmax for apo-HRP-TPyP was around 447 nm, while for TPyP, alone, it increased to 463 nm, which showed that the aromatic groups' surroundings changed upon substitution of porphyrins in a low polar environment.

Nano-structured hybrid molybdenum carbides/nitrides generated in situ for HER applications

2017 ◽  
Vol 5 (17) ◽  
pp. 7764-7768 ◽  
Author(s):  
Rajinder Kumar ◽  
Ritu Rai ◽  
Seema Gautam ◽  
Abir De Sarkar ◽  
Nidhi Tiwari ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Precious Metal ◽  
Molybdenum Carbide ◽  
Low Cost ◽  
Metal Free ◽  
Highly Efficient ◽  
Molybdenum Carbides ◽  
Supported Molybdenum Carbide

A highly efficient, low-cost (precious-metal-free), highly stable nanohybrid electrocatalyst containing carbon-supported molybdenum carbide and nitride nanoparticles of size ranging from 8 to 12 nm exhibit excellent HER catalytic activity.

Synthesis and catalytic activity of heteroatom doped metal-free single-wall carbon nanohorns

2016 ◽  
Vol 52 (31) ◽  
pp. 5391-5393 ◽  
Author(s):  
Xiaohui Wu ◽  
Longbin Cui ◽  
Pei Tang ◽  
Ziqi Hu ◽  
Ding Ma ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Single Wall Carbon ◽  
Carbon Nanohorns ◽  
Metal Free ◽  
Single Wall Carbon Nanohorns

The B-C3 and P-C3 species in heteroatom doped nanohorns act as the acidic and basic active sites to promote the reaction.

scholarly journals Noble-Metal-Free NixSy-C3N5 Hybrid Nanosheet with Highly Efficient Photocatalytic Performance

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1089
Author(s):  
Lixiao Han ◽  
Cong Peng ◽  
Jinming Huang ◽  
Linhao Sun ◽  
Shengyao Wang ◽  
...  
Keyword(s):  
Noble Metal ◽  
Active Sites ◽  
Photocatalytic Performance ◽  
Low Cost ◽  
H2 Production ◽  
Apparent Quantum Yield ◽  
Metal Free ◽  
Highly Efficient ◽  
Multifunctional Catalyst ◽  
Photocatalytic Applications

The construction of highly efficient, low-cost and noble-metal-free photocatalysts depends on photocatalytic technology. Recently, N-rich C3N5 has been explored as a novel carbon nitride material with a much narrower band gap (~2.2 eV) than that of traditional C3N4 (~2.7 eV). Planting noble-metal-free active sites on C3N5 to improve its photocatalytic activity is of great significance. Herein, 2D NixSy nanosheet is facially loaded on 2D C3N5 using a hydrothermal procedure under a low temperature. Due to the quick separation of photogenerated carries between C3N5 and NixSy, this inexpensive noble-metal-free NixSy-C3N5 hybrid nanosheet is highly efficient and stable as a multifunctional catalyst in various applications, including photocatalytic H2 production from water and NO removal. Impressively, the apparent quantum yield (AQY) value for H2 production reaches 37.0% (at 420 nm) on optimal NixSy-C3N5 hybrids, which is much higher than that of Pt-C3N5 material. This work opens an avenue to the fabrication of low-cost and noble-metal-free catalysts for multifunctional photocatalytic applications.

scholarly journals Effect of Na2O Doping on the Surface and Catalytic Properties of the Mn2O3/Al2O3 System

1995 ◽  
Vol 12 (2) ◽  
pp. 119-128 ◽  
Author(s):  
G.A. El-Shobaky ◽  
A.M. Ghozza ◽  
S. Hammad
Keyword(s):  
Catalytic Activity ◽  
Active Sites ◽  
Catalytic Properties ◽  
Xrd Analysis ◽  
Manganese Carbonate ◽  
Oxidation Of Co ◽  
Mechanical Mixing ◽  
Catalytic Activities ◽  
Specific Catalytic Activity ◽  
Catalytically Active

Manganese/aluminium mixed oxide solids having the formula 0.2MnCO3/Al2O3 were prepared by mechanical mixing of a known weight of finely powdered manganese carbonate and aluminium hydroxide. The solids obtained were treated with NaNO3 (0.75–6 mol%) solution and dried at 110°C, then calcined in air at 500°C and 800°C for 6 h. The phases produced were identified by XRD analysis. The surface properties (SBET, Vp and r̄) of the pure and doped solids were studied by using N2 adsorption at – 196°C and their catalytic activities were determined by studying the oxidation of CO by O2at 125–300°C. The results obtained reveal that pure and doped mixed solids preheated in air at 500°C and 800°C consist of Mn2O3 (partridgite) and a poorly crystalline γ-alumina. Doping with sodium oxide at 500°C and 800°C resulted in a small decrease (14–19%) in the SBET value of the treated solids. However, this treatment brought about a significant modification in the catalytic activity of the doped solids. Doping with 0.75% Na2O at 500°C led to an increase of about 30–50% in the specific catalytic activity which was found to decrease on increasing the percentage of Na2O above this limit, falling to values smaller than that measured for the undoped catalyst. Doping at 800°C led to a progressive decrease in the activity of the treated solid to an extent proportional to the amount of dopant present. The doping process at 500°C and 800°C did not modify the mechanism of the catalytic reaction but altered the number of catalytically-active sites contributing in the catalysis of CO oxidation by O2 without changing their energetic nature.

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