Binary CuO/TiO2 nanocomposites as high-performance catalysts for tandem hydrogenation of nitroaromatics
20 Nov 2021-Colloids and Surfaces A: Physicochemical and Engineering Aspects (Elsevier)-Vol. 629, pp 127383
TL;DR: In this article, inexpensive CuO/TiO2 nanocomposites were systematically screened their performance for catalyzing dehydrogenation of ammonia borane (AB) and the tandem hydrogenation of some nitroaromatics.
About: This article is published in Colloids and Surfaces A: Physicochemical and Engineering Aspects.The article was published on 2021-11-20. It has received 9 citations till now. The article focuses on the topics: Dehydrogenation & Ammonia borane.
Citations
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TL;DR: In this article , the effects of vertical load and sliding velocity on tribological morphology of T6 treatment composites were investigated, demonstrating that with the increase of vertical loads, the wear rate and the surface roughness showed a decreasing and then increasing trend with the increasing of sliding velocity.
3 citations
TL;DR: In this article , a dual Z-scheme Cu|Cu 2 O/TiO 2 /CuO photocatalyst composite film is successfully prepared through chemical oxidation, in situ growth, sol-gel spin coating and high temperature calcination methods.
2 citations
TL;DR: In this article , a flexible and mild fabricating protocol is proposed to modulate ordered growing and dispersive depositing of Pt@Cu bimetal layered nanostructure on titanium dioxide nanotubes (TiO2•NTs) via reasonably regulating addition sequence and dosage for the reactants and additives.
Abstract: A flexible and mild fabricating protocol, i.e., stepwise reduction and in situ loading route, is proposed to modulate ordered growing and dispersive depositing of Pt@Cu bimetal layered nanostructure on titanium dioxide nanotubes (TiO2‐NTs) via reasonably regulating addition sequence and dosage for the reactants and additives. Comprehensive characterizations demonstrate that most of the Cu core‐Pt shell nanocrystals with a mean size of 10 nm evenly disperse on the surface of TiO2‐NTs, and a small number of nanocrystals permeate into the nanotubes. In comparison to TiO2‐NTs, the specific surface area declines after loading bimetals, with the pore size distribution shifting from micropores to mesopores. The catalytic activity of the Pt@Cu(x)/TiO2 for hydrolytic hydrogen evolution presents an increasing tendency as the bimetal loadings rise, each surpassing that of the bare bimetal nanocrystals. The H2 generating rate gradually rises with temperature increment. The AB hydrolysis catalyzed by Pt@Cu(9%)/TiO2 at the given temperatures (293–313 K) is affirmed as a first‐order reaction, with apparent activation energy of 28.43 kJ mol−1 and TOF value of 107.27 min−1. The catalyst Pt@Cu(9%)/TiO2 unfolds exceptionally high stability, remaining 91% initial catalytic activity after five cycling use.
1 citations
TL;DR: In this paper , carboxymethyl cellulose (CMC) encapsulated copper oxide-titanium oxide (CuO-TiO2) nanocomposite beads were applied as a promising catalyst for the catalytic reduction of organic and inorganic contaminants; nitrophenols (NP), methyl orange (MO), eosin yellow (EY) and potassium hexacyanoferrate (K3[Fe(CN)6]) in the presence of reducing agent (NaBH4).
Abstract: In this work, we have developed novel beads based on carboxymethyl cellulose (CMC) encapsulated copper oxide-titanium oxide (CuO-TiO2) nanocomposite (CMC/CuO-TiO2) via Al+3 cross-linking agent. The developed CMC/CuO-TiO2 beads were applied as a promising catalyst for the catalytic reduction of organic and inorganic contaminants; nitrophenols (NP), methyl orange (MO), eosin yellow (EY) and potassium hexacyanoferrate (K3[Fe(CN)6]) in the presence of reducing agent (NaBH4). CMC/CuO-TiO2 nanocatalyst beads exhibited excellent catalytic activity in the reduction of all selected pollutants (4-NP, 2-NP, 2,6-DNP, MO, EY and K3[Fe(CN)6]). Further, the catalytic activity of beads was optimized toward 4-nitrophenol with varying its concentrations and testing different concentrations of NaBH4. Beads stability, reusability, and loss in catalytic activity were investigated using the recyclability method, in which the CMC/CuO-TiO2 nanocomposite beads were tested several times for the reduction of 4-NP. As a result, the designed CMC/CuO-TiO2 nanocomposite beads are strong, stable, and their catalytic activity has been proven.
References
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TL;DR: A critical appraisal of different synthetic approaches to Cu and Cu-based nanoparticles and copper nanoparticles immobilized into or supported on various support materials (SiO2, magnetic support materials, etc.), along with their applications in catalysis.
Abstract: The applications of copper (Cu) and Cu-based nanoparticles, which are based on the earth-abundant and inexpensive copper metal, have generated a great deal of interest in recent years, especially in the field of catalysis. The possible modification of the chemical and physical properties of these nanoparticles using different synthetic strategies and conditions and/or via postsynthetic chemical treatments has been largely responsible for the rapid growth of interest in these nanomaterials and their applications in catalysis. In addition, the design and development of novel support and/or multimetallic systems (e.g., alloys, etc.) has also made significant contributions to the field. In this comprehensive review, we report different synthetic approaches to Cu and Cu-based nanoparticles (metallic copper, copper oxides, and hybrid copper nanostructures) and copper nanoparticles immobilized into or supported on various support materials (SiO2, magnetic support materials, etc.), along with their applications i...
1,823 citations
395 citations
TL;DR: In this article, a facile, environmentally friendly route is demonstrated for the synthesis of Pt-Au dendrimer-like nanoparticles on the surface of polydopamine (PDA)-wrapped reduced graphene oxide (RGO), in which Pt alloy nanoparticles are synthesized by the reduction of H2PtCl6 and HAuCl4 with ascorbic acid.
Abstract: A facile, environmentally friendly route is demonstrated for the synthesis of Pt–Au dendrimer-like nanoparticles on the surface of polydopamine (PDA)-wrapped reduced graphene oxide (RGO), in which Pt–Au alloy nanoparticles are synthesized by the reduction of H2PtCl6 and HAuCl4 with ascorbic acid. The effects of support material and chemical composition on the catalytic activity for the reduction of 4-nitrophenol (4-NP) are investigated in detail. Pt nanoparticles supported on PDA/RGO (Pt-PDA/RGO) exhibit significantly higher catalytic activity as compared to those exhibited by Pt nanoparticles deposited on pristine graphene sheets (Pt-RGO) and commercial Pt/C catalyst. Furthermore, the chemical composition seriously affects the catalytic ability of the catalysts. With Pt-to-Au molar ratios of 3/1 and 1/1, significantly enhanced catalytic activities are observed, outperforming the support decorated with each single constituent. The high activity of Pt-Au-PDA/RGO can be explained by electronic effect involving in two types of electron transfers: (1) from the PDA coating to both Au and Pt atoms; (2) from Au to Pt atoms. Moreover, the Pt3Au1-PDA/RGO composite keeps a stable conversion efficiency of around 100% over six successive reduction reaction cycles. Through an experimental device of “filtering and catalyzing,” the Pt3Au1- PDA/RGO sample exhibits superior efficiency for the purification of water containing 4-NP. Within 8 s, the water becomes colorless.
327 citations
TL;DR: It is shown that atomically dispersed Pt over α-molybdenum carbide (α-MoC) constitutes a highly CO-resistant catalyst for the chemoselective hydrogenation of nitrobenzene derivatives and shows promising activity in the presence of 5,000 ppm CO.
Abstract: The hydrogenation activity of noble metal, especially platinum (Pt), catalysts can be easily inhibited by the presence of a trace amount of carbon monoxide (CO) in the reaction feeds. Developing CO-resistant hydrogenation catalysts with both high activity and selectivity is of great economic interest for industry as it allows the use of cheap crude hydrogen and avoids costly product separation. Here we show that atomically dispersed Pt over α-molybdenum carbide (α-MoC) constitutes a highly CO-resistant catalyst for the chemoselective hydrogenation of nitrobenzene derivatives. The Pt1/α-MoC catalyst shows promising activity in the presence of 5,000 ppm CO, and has a strong chemospecificity towards the hydrogenation of nitro groups. With the assistance of water, high hydrogenation activity can also be achieved using CO and water as a hydrogen source, without sacrificing selectivity and stability. The weakened CO binding over the electron-deficient Pt single atom and a new reaction pathway for nitro group hydrogenation confer high CO resistivity and chemoselectivity on the catalyst. Atomically dispersed Pt on an α-MoC support exhibits high CO tolerance during selective hydrogenation of nitrobenzene and its derivatives.
250 citations
TL;DR: In this article, a green synthetic Au NPs/CTS/AC has been proved to be a viable and potential material for environmental pollution treatment of nitrophenols and azo dyes hydrogenation.
Abstract: Herein, chitosan (CTS) functionalized activated coke (AC) is proposed as an excellent platform for Au nanoparticles (NPs) anchoring. Due to the surface-rich hydroxyl and amino groups, CTS can act as a three-functional agent such as reductant, linker and stabilizer to improve the stability of catalysts and realize a green synthesis without adding any additional chemicals. The Au NPs/CTS/AC catalysts exhibited a high catalytic activity in hydrogenation of 4-nitrophenol with the rate constant kapp of 0.6994 min−1 and turnover frequency (TOF) of 202 h−1. Several effect parameters: Au loading amount, environmental water samples and common anions were discussed in detail. Besides, the pH and dissolved oxygen (DO) in different environmental water were measured. The results show that although the catalytic performance of Au NPs/CTS/AC was inhibited in some extent, it could maintain a relatively high catalytic activity in real water samples. In addition, the as-prepared catalysts also displayed high catalytic activity in the hydrogenation of various different substituent nitrophenols and azo dyes, indicating the generality of catalysts, and showed good recyclability with the catalytic performance remained 90% within 7 min 40 s over six recycles. The mechanism of green synthetic pathway and catalytic hydrogenation of nitrophenols over Au NPs/CTS/AC was proposed. The results demonstrated that the Au NPs could facilitate Au-H intermediates to form and thus enhance the catalytic activity. This green synthetic Au NPs/CTS/AC has been proved to be a viable and potential material for environmental pollution treatment of nitrophenols and azo dyes hydrogenation.
203 citations