scholarly journals Controllable preparation and electrocatalytic hydrogen evolution characteristics of Fe3S4 nanocrystals

2022 ◽  
Vol 5 (1) ◽  
pp. 8
Author(s):  
Mingxia Li ◽  
Ni Xiong ◽  
Xin Zhou ◽  
Weiqi Li
Keyword(s):  
Catalytic Activity ◽  
Carbon Black ◽  
Hydrogen Evolution ◽  
Particle Morphology ◽  
Electrochemical Stability ◽  
Sulfur Source ◽  
Reaction Conditions ◽  
Evolution Characteristics ◽  
Controllable Preparation ◽  
A Current

In order to obtain better electrocatalytic hydrogen evolution performance, Fe3S4 with different morphologies was synthesized by controlling the reaction conditions. During that progress, the ferric oleate as an iron source, and the sulfur powder dissolved in oleylamine as a sulfur source. Fe3S4 with particle morphology proved to have the best electrochemical catalytic activity after adding 40% carbon black. In dehydrogenation, the overpotential was 234 mV and the Tafel slope was 213 mV/dec at a current density of 10 mA/cm2. Meanwhile, Fe3S4 with a particle morphology exhibited superior electrochemical stability. Therefore, the controllably fabricated Fe3S4 with a particle morphology is a promising electrocatalyst for dehydrogenation.

Chemical etching manipulated local electronic structure upheaval of graphdiyne for efficient hydrogen evolution

2D Materials ◽  
2021 ◽  
Author(s):  
Kaikai Ma ◽  
Yunqi Zhao ◽  
Qingliang Liao ◽  
Zhaozhao Xiong ◽  
Xinting Li ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Catalytic Activity ◽  
Hydrogen Evolution ◽  
Chemical Etching ◽  
Active Sites ◽  
Theoretical Calculations ◽  
Great Expectation ◽  
Local Electronic Structure ◽  
A Current ◽  
Carbon Based

Abstract Graphdiyne (GDY), featured with unique sp2, sp-hybridized form and inherent inhomogeneous electron distribution, retains great expectation to be developed into highly efficient electrocatalysts for hydrogen evolution reaction (HER). However, the state-of-the-art GDY-based electrocatalysts still suffer from weak catalytic activity and sluggish reaction kinetics originating from the severe scarcity of in-plane active sites and insufficient electrical conductivity. Targeted at this bottleneck issue, electronic structure regulation, recognized as an extremely precise technical route, is promising to improve HER performances of carbon-based electrocatalysts. Herein, a facile controllable chemical etching strategy is well leveraged to introduce sp2-hybridized carbon-oxygen bonds (Csp2-O) into GDY for precise manipulation both of its electronic and spatial structures. Experimental results and theoretical calculations coherently manifest that Csp2-O introduction into GDY can not only induce its electronic structure upheaval to strengthen surface electron transport capability, but also trigger intensive carbon-oxygen p-p orbital hybridization to enhance the catalytic activity of acetylenic bond sites. As a result, the optimal GDY sample after etching delivers excellent HER performance with an overpotential of only 101 mV at a current density of 10 mA cm-2 and a low Tafel slope of 54 mV dec-1, which surpasses most of reported metal-free based electrocatalysts. This work provides a universal route for precise modulation of inherent electronic structure in GDY, and can be further extended to boost the overall performances of other carbon-based catalysts

Mixed MoS2/MoO3 Nanostructures for Hydrogen Evolution Reaction

2021 ◽  
Vol 21 (4) ◽  
pp. 2500-2510
Author(s):  
Umair Aftab ◽  
Hamza Majeed Ansari ◽  
Muhammad Ishaque Abro ◽  
Muhmmad Moazam Baloch ◽  
Sirajuddin ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Low Cost ◽  
Future Generation ◽  
Superior Performance ◽  
Sulfur Source ◽  
The Future ◽  
Earth Abundant ◽  
Future Technologies

The electrolysis of water has paved the way towards a clean, efficient and renewable energy source for the future technologies. Therefore, an efficient electrocatalyst is needed. MoS2 based nonprecious materials are earth-abundant, low cost and promising for the hydrogen evolution reaction. In this study, the effect of sulfur source on the catalytic properties of the MoS2 nanostructures is investigated. Two different sulfur precursors (i.e., thiourea and L-cysteine) were used for the synthesis of MoS2 nanostructures. The optimization of the sulfur precursor content was carried out to report the best for the development of the future generation of HER catalysts. The cysteine assisted synthesis results the mixed MoO3/MoS2 composite structure which has shown significant effect on the catalytic activity. The low concentrations of cysteine and thiourea have shown excellent catalytic activity and stability in 0.5 M H2SO4. TheMoS2 nanostructures with the cysteine as sulfur precursor have shown low Tafel slope of 81 mV dec-1 and a current density of 30 mA cm-2 is obtained at 0.45 V versus RHE. The superior performance of cysteine-based MoS2 sample is due to the rapid charge transfer as confirmed by EIS and excellent conductivity as witnessed by low optical band gap. These findings strengthen the understanding of fundamental science of Mo-based catalysts for the development of the future generation of electrocatalysts and energy conversion technologies.

A highly stable CoMo2S4/Ni3S2 heterojunction electrocatalyst for efficient hydrogen evolution

2021 ◽  
Author(s):  
Minmin Wang ◽  
Mengke Zhang ◽  
Wenwu Song ◽  
Weiting Zhong ◽  
Xunyue Wang ◽  
...  
Keyword(s):  
Hydrogen Evolution ◽  
Current Density ◽  
A Current

A CoMo2S4/Ni3S2 heterojunction is prepared with an overpotential of only 51 mV to drive a current density of 10 mA cm−2 in 1 M KOH solution and ∼100% of the potential remains in the ∼50 h chronopotentiometric curve at 10 mA cm−2.

scholarly journals Bio-Derived Catalysts: A Current Trend of Catalysts Used in Biodiesel Production

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 812
Author(s):  
Hoang Chinh Nguyen ◽  
My-Linh Nguyen ◽  
Chia-Hung Su ◽  
Hwai Chyuan Ong ◽  
Horng-Yi Juan ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Fossil Fuels ◽  
Current Trend ◽  
Biodiesel Production ◽  
High Catalytic Activity ◽  
Promising Alternative ◽  
Advantages And Disadvantages ◽  
Biodiesel Synthesis ◽  
Alkali Catalysts ◽  
A Current

Biodiesel is a promising alternative to fossil fuels and mainly produced from oils/fat through the (trans)esterification process. To enhance the reaction efficiency and simplify the production process, various catalysts have been introduced for biodiesel synthesis. Recently, the use of bio-derived catalysts has attracted more interest due to their high catalytic activity and ecofriendly properties. These catalysts include alkali catalysts, acid catalysts, and enzymes (biocatalysts), which are (bio)synthesized from various natural sources. This review summarizes the latest findings on these bio-derived catalysts, as well as their source and catalytic activity. The advantages and disadvantages of these catalysts are also discussed. These bio-based catalysts show a promising future and can be further used as a renewable catalyst for sustainable biodiesel production.

Synthesis of hierarchical MoSe2 nanolayers on sodium sulfide crystals for electrocatalytic hydrogen evolution

CrystEngComm ◽  
2021 ◽  
Author(s):  
Xiaoshuang Chen ◽  
Meina Ju ◽  
Kun Song ◽  
Guoli Chen ◽  
Rui Yang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Evolution ◽  
High Performance ◽  
Sodium Sulfide ◽  
Hydrogen Generation ◽  
Clean Energy

Hydrogen generation via water electroreduction is a pivotal portion of exploiting clean-energy skills. Nevertheless, developing a low price and high-performance catalytic activity substance to take the place of expensively precious...

Synergetic Effect of Ni2P and MXene Enhances Catalytic Activity in the Hydrogen Evolution Reaction

2021 ◽  
Vol 60 (3) ◽  
pp. 1604-1611
Author(s):  
Zepeng Lv ◽  
Meng Wang ◽  
Dong Liu ◽  
Kailiang Jian ◽  
Run Zhang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Synergetic Effect

scholarly journals Ring-Opening Copolymerization of Cyclohexene Oxide and Cyclic Anhydrides Catalyzed by Bimetallic Scorpionate Zinc Catalysts

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1651
Author(s):  
Felipe de la Cruz-Martínez ◽  
Marc Martínez de Sarasa Buchaca ◽  
Almudena del Campo-Balguerías ◽  
Juan Fernández-Baeza ◽  
Luis F. Sánchez-Barba ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Reaction Mechanism ◽  
Catalytic System ◽  
Phthalic Anhydride ◽  
Ring Opening ◽  
High Selectivity ◽  
Zinc Complexes ◽  
Cyclohexene Oxide ◽  
Reaction Conditions ◽  
Cyclic Anhydrides

The catalytic activity and high selectivity reported by bimetallic heteroscorpionate acetate zinc complexes in ring-opening copolymerization (ROCOP) reactions involving CO2 as substrate encouraged us to expand their use as catalysts for ROCOP of cyclohexene oxide (CHO) and cyclic anhydrides. Among the catalysts tested for the ROCOP of CHO and phthalic anhydride at different reaction conditions, the most active catalytic system was the combination of complex 3 with bis(triphenylphosphine)iminium as cocatalyst in toluene at 80 °C. Once the optimal catalytic system was determined, the scope in terms of other cyclic anhydrides was broadened. The catalytic system was capable of copolymerizing selectively and efficiently CHO with phthalic, maleic, succinic and naphthalic anhydrides to afford the corresponding polyester materials. The polyesters obtained were characterized by spectroscopic, spectrometric, and calorimetric techniques. Finally, the reaction mechanism of the catalytic system was proposed based on stoichiometric reactions.

scholarly journals Defect-Rich Heterogeneous MoS2/rGO/NiS Nanocomposite for Efficient pH-Universal Hydrogen Evolution

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 662 ◽  
Author(s):  
Guangsheng Liu ◽  
Kunyapat Thummavichai ◽  
Xuefeng Lv ◽  
Wenting Chen ◽  
Tingjun Lin ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Hydrogen Evolution ◽  
Hydrogen Evolution Reaction ◽  
Active Sites ◽  
Reduced Graphene ◽  
Heterogeneous Interfaces ◽  
Wide Ph Range ◽  
Ph Range ◽  
A Current ◽  
Poor Stability

Molybdenum disulfide (MoS2) has been universally demonstrated to be an effective electrocatalytic catalyst for hydrogen evolution reaction (HER). However, the low conductivity, few active sites and poor stability of MoS2-based electrocatalysts hinder its hydrogen evolution performance in a wide pH range. The introduction of other metal phases and carbon materials can create rich interfaces and defects to enhance the activity and stability of the catalyst. Herein, a new defect-rich heterogeneous ternary nanocomposite consisted of MoS2, NiS and reduced graphene oxide (rGO) are synthesized using ultrathin αNi(OH)2 nanowires as the nickel source. The MoS2/rGO/NiS-5 of optimal formulation in 0.5 M H2SO4, 1.0 M KOH and 1.0 M PBS only requires 152, 169 and 209 mV of overpotential to achieve a current density of 10 mA cm−2 (denoted as η10), respectively. The excellent HER performance of the MoS2/rGO/NiS-5 electrocatalyst can be ascribed to the synergistic effect of abundant heterogeneous interfaces in MoS2/rGO/NiS, expanded interlayer spacings, and the addition of high conductivity graphene oxide. The method reported here can provide a new idea for catalyst with Ni-Mo heterojunction, pH-universal and inexpensive hydrogen evolution reaction electrocatalyst.

Controllable preparation of CuO/Cu2O composite particles with enhanced photocatalytic performance

2020 ◽  
Vol 44 (16) ◽  
pp. 6369-6374
Author(s):  
Qing Jiang ◽  
Jiajie Jiang ◽  
Runkang Deng ◽  
Xinyuan Xie ◽  
Jianxin Meng
Keyword(s):  
Catalytic Activity ◽  
Photocatalytic Performance ◽  
Composite Particles ◽  
Peg 400 ◽  
Photogenerated Electrons ◽  
Controllable Preparation

Spherical CuO/Cu2O nanocomposites synthesized in PEG-400 have excellent catalytic activity because of transferring photogenerated electrons from Cu2O to CuO.

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