scholarly journals Anionic polyelectrolytes in titanosilicate molecular sieve synthesis towards simultaneously accomplishing low production cost and high catalytic activity

RSC Advances ◽  
2018 ◽  
Vol 8 (38) ◽  
pp. 21363-21368 ◽  
Author(s):  
Kairui Fu ◽  
Jingui Wang ◽  
Yichen Wang ◽  
Yuanchao Shao ◽  
Jiaqi Zhu ◽  
...  

Anionic polyelectrolytes can help to directly achieve low-cost, titanium-rich, diffusion restriction-free and 100%-yield titanium silicalite-1.

2020 ◽  
Vol 8 (4) ◽  
pp. 429-439
Author(s):  
Ying Tao ◽  
Rong Li ◽  
Ai-Bin Huang ◽  
Yi-Ning Ma ◽  
Shi-Dong Ji ◽  
...  

AbstractAmong the transition metal oxide catalysts, manganese oxides have great potential for formaldehyde (HCHO) oxidation at ambient temperature because of their high activity, nontoxicity, low cost, and polybasic morphologies. In this work, a MnO2-based catalyst (M-MnO2) with an interconnected network structure was successfully synthesized by a one-step hydrothermal method. The M-MnO2 catalyst was composed of the main catalytic agent, δ-MnO2 nanosheets, dispersed in a nonactive framework material of γ-MnOOH nanowires. The catalytic activity of M-MnO2 for HCHO oxidation at room temperature was much higher than that of the pure δ-MnO2 nanosheets. This is attributed to the special interconnected network structure. The special interconnected network structure has high dispersion and specific surface area, which can provide more surface active oxygen species and higher surface hydroxyl groups to realize rapid decomposition of HCHO.


2021 ◽  
Author(s):  
Xiaoying Gao ◽  
Xuan Xie ◽  
Kanjun Sun ◽  
Xiaofei Lei ◽  
Tianyu Hou ◽  
...  

Fe, N co-doped carbon electrocatalyst is one of the most attractive alternatives to Pt/C catalysts due to its high catalytic activity, excellent stability and low cost. However, obtaining stable and...


Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2115 ◽  
Author(s):  
Anna Ilnicka ◽  
Malgorzata Skorupska ◽  
Piotr Romanowski ◽  
Piotr Kamedulski ◽  
Jerzy P. Lukaszewicz

The constantly growing demand for active, durable, and low-cost electrocatalysts usable in energy storage devices, such as supercapacitors or electrodes in metal-air batteries, has triggered the rapid development of heteroatom-doped carbon materials, which would, among other things, exhibit high catalytic activity in the oxygen reduction reaction (ORR). In this article, a method of synthesizing nitrogen-doped graphene is proposed. Few-layered graphene sheets (FL-graphene) were prepared by electrochemical exfoliation of commercial graphite in a Na2SO4 electrolyte with added calcium carbonate as a separator of newly-exfoliated FL-graphene sheets. Exfoliated FL-graphene was impregnated with a suspension of green algae used as a nitrogen carrier. Impregnated FL-graphene was carbonized at a high temperature under the flow of nitrogen. The N-doped FL-graphene was characterized through instrumental methods: high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. Electrochemical performance was determined using cyclic voltamperometry and linear sweep voltamperometry to check catalytic activity in ORR. The N-doped electroexfoliated FL-graphene obeyed the four-electron transfer pathways, leading us to further test these materials as electrode components in rechargeable zinc-air batteries. The obtained results for Zn-air batteries are very important for future development of industry, because the proposed graphene electrode materials do not contain any heavy and noble metals in their composition.


2021 ◽  
Author(s):  
Junfang Cheng ◽  
Pandian Ganesan ◽  
Ziling Wang ◽  
Ming Zhang ◽  
Guozhu Zhang ◽  
...  

Perovskite oxides with a low cost and high catalytic activity are considered as suitable candidate for oxygen evolution reaction (OER)/oxygen reduction reaction (ORR), whereas most of them favor only either...


2021 ◽  
Vol 9 ◽  
Author(s):  
Meng Liu ◽  
Zihan Huang ◽  
Wei Wei ◽  
Xiangyu Wang ◽  
Yiqiang Wen

Developing an effective and low-cost system to synthesize titanium silicalite-1 (TS-1) zeolite is desirable for a range of industrial applications. To date, the poor catalytic activity of the synthesized zeolite due to the low amount of framework titanium and large crystal size is the main obstacle limiting the widespread application of this material. Moreover, a large amount of wastewater is often produced by the existing synthesis process. Herein, a green and sustainable route for synthesizing small-crystal TS-1 with a high fraction of framework Ti was demonstrated via a seed-assisted method using a tetrapropylammonium bromide (TPABr)-ethanolamine hydrothermal system. The influence of the synthesis conditions on the physicochemical properties and catalytic activities of TS-1 was investigated. With the assistance of nanosized S-1 seeds, the incorporation of Ti into the framework of TS-1 was promoted, and the crystallization rate was effectively accelerated. After alkaline etching, the obtained hierarchical TS-1 had higher catalytic activity towards propylene epoxidation with an extremely high turnover frequency of 1,650 h−1. Furthermore, the mother liquid during the hydrothermal reaction could be reused for the next synthesis procedure. Consequently, utilization ratios of both ethanolamine and TPABr exceeding 95% were achieved by recycling the mother liquid. This low-cost approach for reducing wastewater could be easily scaled up to provide a promising synthesis method for the industrial production of TS-1 and other topological zeolites.


Nanoscale ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 1985-1993 ◽  
Author(s):  
Yuyang Qi ◽  
Long Zhang ◽  
Lan Sun ◽  
Guanjun Chen ◽  
Qiaomei Luo ◽  
...  

Electrocatalysts with high catalytic activity, high stability and low cost are critical to the hydrogen evolution reaction (HER).


2019 ◽  
Author(s):  
Disha Jain

<p>Supported Ni catalysts are extensively studied for methane reforming due to their high catalytic activity and low cost. However, these catalysts undergo deactivation due to coke deposition and oxidation of Ni particles. In the present work, Ni and Pt substituted CoTiO<sub>3</sub> were synthesized and studied for steam (SRM) and dry (DRM) reforming of methane. The catalytic activity of monometallic and bimetallic Ni-Pt catalyst was compared for SRM and reducibility studies were done to highlight the change in metal-support interaction in the synthesized samples. Ex situ and in situ characterization were performed to understand the change in catalyst surface and the nature of surface intermediates formed during the reaction. Consequently, surface reaction mechanism was proposed and kinetic parameters were determined by fitting experimental data.</p><br>


2019 ◽  
Author(s):  
Disha Jain

<p>Supported Ni catalysts are extensively studied for methane reforming due to their high catalytic activity and low cost. However, these catalysts undergo deactivation due to coke deposition and oxidation of Ni particles. In the present work, Ni and Pt substituted CoTiO<sub>3</sub> were synthesized and studied for steam (SRM) and dry (DRM) reforming of methane. The catalytic activity of monometallic and bimetallic Ni-Pt catalyst was compared for SRM and reducibility studies were done to highlight the change in metal-support interaction in the synthesized samples. Ex situ and in situ characterization were performed to understand the change in catalyst surface and the nature of surface intermediates formed during the reaction. Consequently, surface reaction mechanism was proposed and kinetic parameters were determined by fitting experimental data.</p><br>


2021 ◽  
Vol 21 (10) ◽  
pp. 5319-5328
Author(s):  
Sha-Sha Luo ◽  
Yu-Meng Ma ◽  
Peng-Wei Li ◽  
Ming-Hua Tian ◽  
Qiao-Xia Li

Transition metal and nitrogen co-doped carbon-based catalysts (TM-N-C) have become the most promising catalysts for Pt/C due to their wide range of sources, low cost, high catalytic activity, excellent stability and strong resistance to poisoning, especially Fe–N–C metal-organic frameworks (MOFs), which are some of the most promising precursors for the preparation of Fe–N–C catalysts due to their inherent properties, such as their highly ordered three-dimensional framework structure, controlled porosity, and tuneable chemistry. Based on these, in this paper, different iron sources were added to synthesis a sort of zeolitic imidazole frameworks (ZIF-8). Then the imidazole salt in ZIF-8 was rearranged into high N-doped carbon by high-temperature pyrolysis to prepare the Fe–N–C catalyst. We studied the physical characteristics of the catalysts by different iron sources and their effects on the catalytic properties of the oxygen reduction reaction (ORR). From the point of morphology, various iron sources have a positive influence on maintaining the morphology of ZIF-8 polyhedron. Fe–N/C–Fe(NO3)3 has the same anion as zinc nitrate, and can maintain a polyhedral morphology after high-temperature calcination. It had the highest ORR catalytic activity compared to the other four catalyst materials, which proved that there is a certain relationship between morphology and performance. This paper will provide a useful reference and new models for the development of high-performance ORR catalysts without precious metals.


2014 ◽  
Vol 781 ◽  
pp. 79-94 ◽  
Author(s):  
A. Nithya ◽  
Kandasamy Jothivenkatachalam ◽  
S. Prabhu ◽  
K. Jeganathan

Heterogeneous photocatalysis is a significant technology for environmental application. Moreover, immobilising an appropriate catalyst on the surface of a natural organic polymer presents a number of additional advantages including low-cost, high catalytic activity and extensive potential reuse for the application of pharmaceutical, biomedical and industrial activities. This review mainly focuses on the role of chitosan based material as photocatalyst on the environmental remediation.


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