Visualizing reactant molecules induced lattice breath of catalyst and its role for activity enhancement

2020 ◽  
Author(s):  
Zhifei Hao ◽  
Guoquan Liu ◽  
Hao Zhang ◽  
Yi Li ◽  
Haitao Wang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Energy Barrier ◽  
Catalytic Performance ◽  
Lattice Expansion ◽  
Reduction Of No ◽  
Surface Change ◽  
Rate Determining Step ◽  
Fine Surface ◽  
Activity Enhancement

Abstract Recently, a few in situ observations showed that reactant molecules can induce the hyper-fine surface change of catalyst under realistic conditions. However, hardly any report further illustrated that whether and how could this phenomenon affect the catalytic performance. Herein, using in situ TEM, we visually captured the reversible lattice expansion of Pt-WO3-x catalyst induced by NO in exemplified reduction of NO with H2. Results showed that the NO could adsorb on the oxygen vacancy sites and energetic favorably induced the reversible stretching of W-O-W bonds. 20% enhancement of catalytic activity was then correlated with this lattice expansion. Moreover, DFT calculations showed that the lattice expansion can reduce the adsorption energy of NO on Pt4 centers and also the energy barrier of the rate-determining step.

scholarly journals Ultra-Small Pd(0) Nanoparticles into a Designed Semisynthetic Lipase: An Efficient and Recyclable Heterogeneous Biohybrid Catalyst for the Heck Reaction under Mild Conditions

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2358 ◽  
Author(s):  
David Lopez-Tejedor ◽  
Blanca de las Rivas ◽  
Jose M. Palomo
Keyword(s):  
Catalytic Activity ◽  
Protein Structure ◽  
Heck Reaction ◽  
Catalytic Performance ◽  
Reducing Agent ◽  
Chemically Modified ◽  
Mild Conditions ◽  
In Situ Formation ◽  
Geobacillus Thermocatenulatus

A novel heterogeneous enzyme-palladium (Pd) (0) nanoparticles (PdNPs) bionanohybrid has been synthesized by an efficient, green, and straightforward methodology. A designed Geobacillus thermocatenulatus lipase (GTL) variant genetically and then chemically modified by the introduction of a tailor-made cysteine-containing complementary peptide- was used as the stabilizing and reducing agent for the in situ formation of ultra-small PdNPs nanoparticles embedded on the protein structure. This bionanohybrid was an excellent catalyst in the synthesis of trans-ethyl cinnamate by Heck reaction at 65 °C. It showed the best catalytic performance in dimethylformamide (DMF) containing 10–25% of water as a solvent but was also able to catalyze the reaction in pure DMF or with a higher amount of water as co-solvent. The recyclability and stability were excellent, maintaining more than 90% of catalytic activity after five cycles of use.

Synthesis and catalytic performance of graphene oxide-Au nanorings composites

2019 ◽  
Vol 12 (03) ◽  
pp. 1950028 ◽  
Author(s):  
Tong Shen ◽  
Zhong Li ◽  
Yue Jiang ◽  
Zai-Gang Luo
Keyword(s):  
Graphene Oxide ◽  
Catalytic Activity ◽  
Rate Constant ◽  
Sodium Borohydride ◽  
Catalytic Performance ◽  
Hybrid Structure ◽  
In Situ Synthesis ◽  
Galvanic Replacement ◽  
Hybrid Nanomaterial

A simple and facile method is described for the in situ synthesis of graphene oxide-Ag nanoplates (GO-AgNPs) hybrid structure and then served as sacrificial templates for producing graphene oxide-Au nanorings (GO-AuNRs) by galvanic replacement taken place on the GO surface. The catalytic activity of the resulting hybrid nanomaterial has been investigated for the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with sodium borohydride (NaBH4). The results showed that the rate constant of GO-AuNRs nanomaterials was 0.205[Formula: see text]min[Formula: see text] and the samples showed significant enhancement in catalytic activity.

MOF-derived Co1.11Te2 with half-metallic character for efficient photochemical conversion of CO2 under visible-light irradiation

2019 ◽  
Vol 55 (48) ◽  
pp. 6862-6865 ◽  
Author(s):  
Yong Xu ◽  
Jiang Mo ◽  
Guanqun Xie ◽  
Dawei Ding ◽  
Shujiang Ding ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Catalytic Activity ◽  
Energy Barrier ◽  
Catalytic Performance ◽  
Carbon Layer ◽  
Low Energy ◽  
High Catalytic Activity ◽  
Key Factors ◽  
Strong Electron ◽  
Half Metallic

Co1.11Te2 enwrapped in a carbon layer displayed high catalytic performance for photocatalytic CO2 reduction. The strong electron transfer ability and the low energy barrier are the key factors that promote its high catalytic activity.

Uniform Ni/SiO2@Au magnetic hollow microspheres: rational design and excellent catalytic performance in 4-nitrophenol reduction

Nanoscale ◽  
2014 ◽  
Vol 6 (12) ◽  
pp. 7025-7032 ◽  
Author(s):  
Shenghuan Zhang ◽  
Shili Gai ◽  
Fei He ◽  
Yunlu Dai ◽  
Peng Gao ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Catalytic Activity ◽  
Rational Design ◽  
Au Nanoparticles ◽  
Catalytic Performance ◽  
Hollow Microspheres ◽  
Nitrophenol Reduction ◽  
Excellent Catalytic Performance

Uniform Ni/SiO2 magnetic hollow microspheres were prepared by an in situ thermal decomposition and reduction route. Tiny Au nanoparticles (5 nm) were linked to Ni/SiO2 microspheres. The as-prepared Ni/SiO2@Au catalysts exhibited excellent catalytic activity for 4-nitrophenol reduction.

scholarly journals Catalytic Oxidation of HCHO over the Sodium-Treated Sepiolite-Supported Rare Earth (La, Eu, Dy, and Tm) Oxide Catalysts

Catalysts ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 328 ◽  
Author(s):  
Ning Dong ◽  
Qing Ye ◽  
Mengyue Chen ◽  
Shuiyuan Cheng ◽  
Tianfang Kang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Rare Earth ◽  
Catalytic Oxidation ◽  
Rare Earth Oxide ◽  
Catalytic Performance ◽  
Rare Earth Oxides ◽  
Hydroxyl Groups ◽  
In Situ Drifts ◽  
The Rare Earth

The sodium-treated sepiolite (NaSep)-supported rare earth oxide (RE/NaSep; RE = La, Eu, Dy, and Tm) samples were prepared using the rotary evaporation method. Physicochemical properties of these materials were characterized by XRD, SEM, BET, FTIR, XPS, H2–TPR, NH3–TPD, and in situ DRIFTS, and their catalytic activities for formaldehyde (HCHO) (2000 ppm) oxidation were evaluated. The results show that loading of the rare earth oxide on NaSep improved its catalytic performance. Among all the samples, Eu/NaSep performed the best, and complete HCHO conversion was achieved at a temperature of 150 °C and a gas hourly space velocity of 240,000 mL/(g h); a good catalytic activity was still maintained after 45 h of stability test. The catalytic oxidation mechanism of HCHO was studied using the in situ DRIFTS technique. As a result, the effective and stable catalytic performance of the Eu/NaSep sample was mainly due to the presence of hydroxyl groups on the sepiolite surface and the doped rare earth oxides, which contributed to its high performance. HCHO oxidation underwent via the steps of HCHO + O2 → HCOO− + OH− → H2O + CO2. It is concluded that the optimal catalytic activity of Eu/NaSep was associated with the highest Oads/Olatt atomic ratio, the largest amount of hydroxyl groups, the highest acidity, and the best reducibility. The present work may provide new insights into the application in the removal of high-concentration HCHO over the rare earth oxides supported on natural low-cost clays.

Catalytic Performance and in Situ Surface Chemistry of Pure α-MnO2 Nanorods in Selective Reduction of NO and N2O with CO

2013 ◽  
Vol 117 (16) ◽  
pp. 8329-8335 ◽  
Author(s):  
Junjun Shan ◽  
Yuan Zhu ◽  
Shiran Zhang ◽  
Tong Zhu ◽  
Sergei Rouvimov ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
Selective Reduction ◽  
Catalytic Performance ◽  
Reduction Of No

In situ immobilization of isolated Pd single-atoms on graphene by employing amino-functionalized rigid molecules and their prominent catalytic performance

2020 ◽  
Vol 10 (2) ◽  
pp. 450-457
Author(s):  
Qicheng Liu ◽  
Jingchun Wang ◽  
Jingzi Zhang ◽  
Yawei Yan ◽  
Xiaoyu Qiu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Catalytic Performance ◽  
Hydrogenation Reaction ◽  
In Situ Immobilization ◽  
Single Atoms

The isolated Pd single atoms anchored on graphene demonstrate a catalytic activity that is 21.3 times higher than that of Pd/C in the RhB hydrogenation reaction.

Facile in situ synthesis of silver nanoparticles on boron nitride nanosheets with enhanced catalytic performance

2015 ◽  
Vol 3 (32) ◽  
pp. 16663-16669 ◽  
Author(s):  
Heng Shen ◽  
Chunting Duan ◽  
Jing Guo ◽  
Ning Zhao ◽  
Jian Xu
Keyword(s):  
Silver Nanoparticles ◽  
Catalytic Activity ◽  
Boron Nitride ◽  
Ag Nanoparticles ◽  
Catalytic Performance ◽  
In Situ Synthesis ◽  
Boron Nitride Nanosheets ◽  
Fe Complex

Ag nanoparticles are in situ decorated on a BNNS modified with a TA–Fe complex, and the nanohybrids show excellent catalytic activity.

Facile in situ redox synthesis of Au@Fe2O3 nanocomposites with multifunctional catalytic activity

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Zhuo Chen ◽  
Xiao-jun Wei ◽  
Jun Liu ◽  
Xiao-meng Lv
Keyword(s):  
Catalytic Activity ◽  
Benzyl Alcohol ◽  
Hybrid Composites ◽  
Synthesis Method ◽  
Catalytic Performance ◽  
High Catalytic Activity ◽  
Oxidation Of Benzyl Alcohol ◽  
Nitrophenol Reduction ◽  
Dispersed Gold

AbstractUsing freshly synthesized Fe(OH)2 matrix and HAuCl4 as precursor, l-lysine as stabilizer and linker, Au nanoparticles coated onto γ-Fe2O3 substrate were in-situ synthesized at room temperature. The Au@Fe2O3 hybrid composites with small highly dispersed gold particles (∼3 nm) exhibited high catalytic activity towards 4-nitrophenol reduction and the oxidation of benzyl alcohol. The results indicated the rate constant for 4-nitrophenol reduction was 5.3 × 10−2 s−1, and displayed efficient catalytic performance in terms of turnover number (TOF) of 134.8 h−1 for the oxidation of benzyl alcohol at 90 ± 1 °C. Furthermore, the facial electrode potential-driven in situ synthesis method paved the way of other metal nanoparticles over Fe2O3.

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