Search query: "cobalt" and "Photocatalytic"

Related papers:

abstract: Semiconductor photocatalysis is a promising technology to tackle refractory antibiotics contamination in water. Herein, a facile in situ growth strategy is developed to implant single atom cobalt in polymeric carbon nitride (pCN) via the bidentate ligand for efficient photocatalytic degradation of oxytetracycline (OTC) The atomic characterizations indicate that single atom cobalt is successfully anchored on pCN by covalently forming the CoO bond and CoN bond, which will strengthen the interaction between single atom cobalt and pCN. This single atom cobalt can efficiently expand optical absorption, increase electron density, facilitate charge separation and transfer, and promote OTC degradation. As the optimal sample, Co(1.28%)pCN presents an outstanding apparent rate constant for OTC degradation (0.038 min 1 under visible light irradiation, which is about 3.7 times than that of the pristine pCN. The electron spin resonance (ESR) tests and reactive species trapping experiments demonstrate that the 1 O2 h+ *O2 and *OH are responsible for OTC degradation. This work develops a new way to construct single atom modified pCN and provides a green and highly efficient strategy for refractory antibiotics removal.
author_names: Yang Yang

Guangming Zeng

Danlian Huang

Chen Hong Zhang

Donghui He

Chengyun Zhou

Wenjun Wang

Weiping Xiong

Biao Song

Huan Yi

Shujing Ye

Xiaoya Ren
title: In Situ Grown Single Atom Cobalt on Polymeric Carbon Nitride with Bidentate Ligand for Efficient Photocatalytic Degradation of Refractory Antibiotics.
venue: Small
year: 2020

abstract: Highly efficient and effective treatments of hazardous dye based color effluents are a major problem in the industrial sector. In this research, the cobalt ferrite (CoFe 2 O 4 catalyst was produced and used for the degradation of Congo red (CR) as a model dye from aqueous solution. For a said purpose, cobalt ferrite (CoFe 2 O 4 nanostructures with photocatalytic degradation potential were engineered via co precipitation method using Fe 2 (SO 4 3 CoO 2 and triethylene glycol (as a stabilizing agent) As prepared, CoFe 2 O 4 nanostructures were further surface functionalized with 3 APTES and tested for CR degradation. The prepared CoFe 2 O 4 nanostructures were characterized by X ray diffraction, Fourier transform infra red (FT IR) scanning electron microscopy (SEM) and Brunauer Emmitt Teller (BET) analysis. UV visible absorption was used to measure the optical band gap of prepared CoFe 2 O 4 nanostructures through Tauc plots. The as prepared CoFe 2 O 4 nanostructure bandgap was found to be 2.71 EV while using an acidic medium. The degradation rates of CR dye for bs CoFe 2 O 4 as CoFe 2 O 4 and fs CoFe 2 O 4 nanostructures at pH 9 were 84, 87, and 92% respectively. Furthermore, the influences of various process parameters, i.e. the effect of catalyst dose, contact time, dye dose/concentration, pH effect, and effect of different acids, were checked for the prepared three types of nanostructures, i.e. bs CoFe 2 O 4 as CoFe 2 O 4 and fs CoFe 2 O 4 The kinetics models properly explained that the reaction of degradation following pseudo first order kinetics.
author_names: Nisar Ali

Amir Said

Farman Ali

Fazal Raziq

Zarshad Ali

Muhammad Bilal

Laurence Reinert

Tasleema Begum

Hafiz M N Iqbal
title: Photocatalytic Degradation of Congo Red Dye from Aqueous Environment Using Cobalt Ferrite Nanostructures: Development, Characterization, and Photocatalytic Performance
venue: Water, Air, Soil Pollution
year: 2020

author_names: Saeid Taghavi Fardood

Reza Forootan

Farzaneh Moradnia

Zolfa Afshari

Ali Ramazani
title: Green synthesis, characterization, and photocatalytic activity of cobalt chromite spinel nanoparticles
year: 2020

abstract: Significance Photocatalysts frequently require simultaneous loading of oxidative and reductive cocatalysts to achieve both efficient half reactions within a single material. Nevertheless, unregulated loading and distribution of two cocatalysts will result in direct contact between oxidation and reduction centers, leading to detrimental charge recombination. This research presents a center/edge approach to load two redox cocatalysts with controlled physical separation in atomistic scale using single atom architecture. This spatial separation is critical for enhancing surface charge separation and achieving efficient H2O2 production. We report that redox cocatalysts are spatially separated on a two dimensional (2D) photocatalyst, which opens an approach for achieving both efficient oxidation and reduction reactions on 2D photocatalysts. Redox cocatalysts play crucial roles in photosynthetic reactions, yet simultaneous loading of oxidative and reductive cocatalysts often leads to enhanced charge recombination that is detrimental to photosynthesis. This study introduces an approach to simultaneously load two redox cocatalysts, atomically dispersed cobalt for improving oxidation activity and anthraquinone for improving reduction selectivity, onto graphitic carbon nitride (C3N4) nanosheets for photocatalytic H2O2 production. Spatial separation of oxidative and reductive cocatalysts was achieved on a two dimensional (2D) photocatalyst, by coordinating cobalt single atom above the void center of C3N4 and anchoring anthraquinone at the edges of C3N4 nanosheets. Such spatial separation, experimentally confirmed and computationally simulated, was found to be critical for enhancing surface charge separation and achieving efficient H2O2 production. This center/edge strategy for spatial separation of cocatalysts may be applied on other 2D photocatalysts that are increasingly studied in photosynthetic reactions.
author_names: Chiheng Chu

Qianhong Zhu

Zhenhua Pan

Srishti Gupta

Dahong Huang

Yonghua Du

Seunghyun Weon

Yueshen Wu

Christopher Muhich

Eli Stavitski

Kazunari Domen

Jae-Hong Kim
title: Spatially separating redox centers on 2D carbon nitride with cobalt single atom for photocatalytic H2O2 production
venue: Proceedings of the National Academy of Sciences
year: 2020

abstract: Environmental pollution and energy scarcity is a major issue of the current scenario which forbear the progress of developing world. To overcome these problems towards a sustainable future, the utilization of sunlight by means of photocatalysis can be regarded as a best and suitable pathway. To validate this purpose, design and development of efficient heterogeneous photocatalyst for harvesting solar energy should be the major research concern for scientific community. In this regard herein, we have prepared a series of stable and efficient CoTiO3/UiO 66 NH2 p n junction mediated heterogeneous photocatalyst by hydrothermal method. The functionalised linker of UiO 66 NH2 provided an intimate interfacial contact with CoTiO3 by Co/TiON ionic interaction, as proved by HRTEM and XPS analysis. Moreover the inverted V shaped Mott Schottky plot confirmed the junction formation in the optimised CoTiO3/UiO 66 NH2 material. In addition, EIS and PL analysis also provides sufficient evidence about the hindrance of active species recombination in composite as a result of p n hetero junction. LC MS characterization technique traces the assorted intermediate species produced in the course of photodegradation of Norfloxacin and confirms its complete degradation to corresponding CO2, H2O and NH4+ by the optimised CoTiO3/UiO 66 NH2. The highest photo catalytic activity obtained towards Norfloxacin degradation is 90.13% and H2 production is 530.87 umol in 1 h. The enhanced photo catalytic reaction follows Type II p n hetero junction charge transfer mechanism and thus, paves a new way to design MOF based heterojunction photocatalyst for diverse photo catalytic performance.
author_names: Satyabrata Subudhi

Lekha Paramanik

Sabiha Sultana

Sriram Mansingh

Priyabrat Mohapatra

Kulamani Parida
title: A type II interband alignment heterojunction architecture of cobalt titanate integrated UiO 66 NH2: A visible light mediated photocatalytic approach directed towards Norfloxacin degradation and green energy (Hydrogen) evolution.
venue: Journal of colloid and interface science
year: 2020

abstract: Abstract Generally, pristine semiconductor materials are difficult to own excellent photocatalytic performance, and doping is considered an effective strategy to improve their performance. Herein, Co doped BiOBr (0 1 0) was successfully synthesized. The improved performance could be attributed to the enhanced charge separation efficiency and the expanded light absorption region. Moreover, Co doped BiOBr (0 1 0) owned relatively rough crystal surface with rich atomic defects and large specific surface area, which leaded to its excellent adsorption performance that contributed to the hole dominated degradation process. Through density functional theoretical (DFT) calculation, the effect of Co doping on electronic structure of BiOBr was investigated, indicating that an additional energy level inserted into the band gap of Co doped BiOBr, the band structure of Co doped BiOBr was more intensive than that of BiOBr, and the CBM and VBM of the Co doped BiOBr shifted towards lower energy regions. Tetracycline hydrochloride was chosen to further evaluate the photocatalytic performance of as prepared Co doped BiOBr (0 1 0) and 83% of tetracycline hydrochloride was degrade within 30 min. Finally, the visible light driven catalytic mechanism of Co doped BiOBr (0 1 0) was elucidated. Thus, a feasible strategy was proposed for the fabrication of excellent visible light driven photocatalytic materials.
author_names: Luhua Shao

Yutang Liu

Longlu Wang

Xinnian Xia

Xiang-Zhong Shen
title: Electronic structure tailoring of BiOBr (0 1 0) nanosheets by cobalt doping for enhanced visible light photocatalytic activity
year: 2020

abstract: Abstract The present work deals with the synthesis, characterization, and testing towards the photochemical degradation efficiency of cobalt oxide (Co3O4) nanoparticles (NPs) Following the synthesis of Co3O4 NPs by the hydrothermal method, the NPs are confirmed to be formed in their cubic lattice structure with the spherical shape morphology. The testing studies revealed that the Co3O4 NPs degraded the Methylene violet (MV) and Crystal violet (CV) dyes very efficiently under the UV light irradiation. A Langmuir Hinshelwood (L H) model has been effectively used to display the adsorption of CV and MV dye molecules taking place using surface monolayer exposure to the UV light. The kinetics and reaction mechanism behind the elimination of CV and MV dyes shows for a pseudo second order kinetics model. With these Co3O4 NPs as photocatalysts, the maximum photodegradation rate was observed to be 92 and 64 for the MV and CV (respectively) within the same period of 45 min and this enhanced photocatalytic performance is due to the effective reduction of electron hole recombination process by the Co3O4 NPs.
author_names: R Sukhin Saravan

M Muthukumaran

S M Mubashera

Manickavasagan Abinaya

P Varun Prasath

R Parthiban

Faruq Mohammad

Won-Chun Oh

Suresh Sagadevan
title: Evaluation of the photocatalytic efficiency of cobalt oxide nanoparticles towards the degradation of crystal violet and methylene violet dyes
year: 2020

abstract: Based on the designed tripodal linker 1,3,5 tris(2 methylimidazol 1 yl)benzene (timb) four cobalt(II) coordination polymers, [Co4(timb)2(Br IPA)4]*5H2O}n (1) [Co(timb)0.5(NH2 IPA)*4H2O}n (2) [Co5(timb)4(OH IPA)4]*2NO3*2DMA*2H2O}n (3) and [Co3(timb)2(SO3 IPA)2(H2O)2]*8H2O}n (4) have been obtained by adjusting the meta functional groups of isophthalic acid (H2IPA) CP 1 displays an unprecedented 3D 3 nodal (3,4,8) connected net with the point (Schlafli) symbol {42*64}{42*6}2{46*614*74*83*9} based on trinuclear {Co3(COO)6} SBUs. CP 2 shows an interesting 2D (3,4) connected {63}{66} bilayer with ABAB packing. CP 3 is a 2D 6 nodal (3,3,3,4,4,4) connected sheet with the point (Schlafli) symbol {4*52}{4*53*72}2{42*52*6*7}3{43}{53}2. CP 4 exhibits a 2D 2D 3D interpenetrating net based on the 2D (3,4) connected {63}{66} bilayer structure. CPs 1 4 possess excellent luminescence sensing properties for Fe3+ and Cr2O72 ions in aqueous solution with high sensitivity and selectivity. Besides, the magnetic properties as well as the photocatalytic activities for the degradation of methylene blue (MB) of CPs 1 4 under visible light have been investigated.
author_names: Junjie Wang

N N Chen

Chen Yi Zhang

Li Jia

Liming Fan
title: Functional group induced structural diversities and photocatalytic, magnetic and luminescence sensing properties of four cobalt(ii) coordination polymers based on 1,3,5 tris(2 methylimidazol 1 yl)benzene
year: 2020

abstract: In this work, we have successfully constructed the cobalt oxo (Co III 4 O 4 cubane complex on polymeric carbon nitride (PCN) through pyridine linkage. The covalently grafted Co III 4 O 4 cubane units were uniformly distributed on the PCN surface. The product exhibited greatly enhanced photocatalytic activities for water oxidation under visible light irradiation. Further characterizations and spectroscopic analyses revealed that the grafted Co III 4 O 4 cubane units could effectively capture the photogenerated holes from excited PCN, lower the overpotential of oxygen evolution reaction (OER) and serve as efficient catalysts to promote the multi electron water oxidation process. This work provides new insight into the future development of efficient photocatalysts by grafting molecular catalysts for artificial photosynthesis.
author_names: Wen-long Zhen

Xu Yuan

Xiangyan Shi

Can Xue
title: Grafting Molecular Cobalt oxo Cubane Catalyst on Polymeric Carbon Nitride for Efficient Photocatalytic Water Oxidation.
venue: Chemistry, an Asian journal
year: 2020

abstract: Abstract Cobalt doped ZnO nanoparticles (Zn1 xCoxO(0.00<=x<=0.1) was synthesized by a two step coprecipitation method using oxalic acid and ammonium hydroxide. The effect of Co doping on the crystallite structure, optical, magnetic and photocatalytic properties of ZnO was investigated. The X ray powder diffraction (XRD) patterns confirmed that all Zn1 xCoxO samples exhibited hexagonal wurtzite structure. Further, the lattice parameters revealed an increasing trend in doped samples which indicated the incorporation of Co ions into the ZnO lattice. The X ray photoelectron spectroscopic (XPS) survey suggested that Co ion incorporated into the ZnO lattice with a Co2+ oxidization state. The scanning electron micrograph (SEM) showed that the average size decreased with increasing doping concentration. Photoluminescence (PL) showed blue emission peak at 475 nm, green emission peak at 545 nm and yellow emission peak at 580 nm, respectively. UV vis spectral illustrated the substitution of Co2+ in ZnO leaded to band gap narrowing. Vibrating sample magnetometer (VSM) demonstrated doped samples exhibited ferromagnetism behavior at room temperature. The Zn0.96Co0.04O sample showed enhancement in the photocatalytic degradation efficiency of methylene blue as compared to the pure ZnO. However, increasing doping concentrations of Co leaded to a decrease of photocatalytic efficiency.
author_names: Hui Pan

Yuchuan Zhang

Yi Hu

Hongxue Xie
title: Effect of cobalt doping on optical, magnetic and photocatalytic properties of ZnO nanoparticles
year: 2020