scholarly journals TiO2 Based Nanostructures for Photocatalytic CO2 Conversion to Valuable Chemicals

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 326 ◽  
Author(s):  
Abdul Razzaq ◽  
Su-Il In
Keyword(s):  
Noble Metals ◽  
Photocatalytic Performance ◽  
Light Trapping ◽  
High Surface ◽  
Three Dimensional ◽  
Value Added ◽  
Co2 Conversion ◽  
Surface Areas ◽  
Tio2 Nanosheets ◽  
Photocatalytic Co2 Conversion

Photocatalytic conversion of CO2 to useful products is an alluring approach for acquiring the two-fold benefits of normalizing excess atmospheric CO2 levels and the production of solar chemicals/fuels. Therefore, photocatalytic materials are continuously being developed with enhanced performance in accordance with their respective domains. In recent years, nanostructured photocatalysts such as one dimensional (1-D), two dimensional (2-D) and three dimensional (3-D)/hierarchical have been a subject of great importance because of their explicit advantages over 0-D photocatalysts, including high surface areas, effective charge separation, directional charge transport, and light trapping/scattering effects. Furthermore, the strategy of doping (metals and non-metals), as well as coupling with a secondary material (noble metals, another semiconductor material, graphene, etc.), of nanostructured photocatalysts has resulted in an amplified photocatalytic performance. In the present review article, various titanium dioxide (TiO2)-based nanostructured photocatalysts are briefly overviewed with respect to their application in photocatalytic CO2 conversion to value-added chemicals. This review primarily focuses on the latest developments in TiO2-based nanostructures, specifically 1-D (TiO2 nanotubes, nanorods, nanowires, nanobelts etc.) and 2-D (TiO2 nanosheets, nanolayers), and the reaction conditions and analysis of key parameters and their role in the up-grading and augmentation of photocatalytic performance. Moreover, TiO2-based 3-D and/or hierarchical nanostructures for CO2 conversions are also briefly scrutinized, as they exhibit excellent performance based on the special nanostructure framework, and can be an exemplary photocatalyst architecture demonstrating an admirable performance in the near future.

scholarly journals Low-Dimensional Nanostructured Photocatalysts for Efficient CO2 Conversion into Solar Fuels

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 418
Author(s):  
Hossam A. E. Omr ◽  
Mark W. Horn ◽  
Hyeonseok Lee
Keyword(s):  
Global Warming ◽  
Noble Metals ◽  
Quantum Confinement Effect ◽  
Resonance Effect ◽  
Value Added ◽  
Solar Fuels ◽  
Localized Surface Plasmon ◽  
Co2 Conversion ◽  
Low Dimensional ◽  
Photocatalytic Co2 Conversion

The ongoing energy crisis and global warming caused by the massive usage of fossil fuels and emission of CO2 into atmosphere continue to motivate researchers to investigate possible solutions. The conversion of CO2 into value-added solar fuels by photocatalysts has been suggested as an intriguing solution to simultaneously mitigate global warming and provide a source of energy in an environmentally friendly manner. There has been considerable effort for nearly four decades investigating the performance of CO2 conversion by photocatalysts, much of which has focused on structure or materials modification. In particular, the application of low-dimensional structures for photocatalysts is a promising pathway. Depending on the materials and fabrication methods, low-dimensional nanomaterials can be formed in zero dimensional structures such as quantum dots, one-dimensional structures such as nanowires, nanotubes, nanobelts, and nanorods, and two-dimensional structures such as nanosheets and thin films. These nanostructures increase the effective surface area and possess unique electrical and optical properties, including the quantum confinement effect in semiconductors or the localized surface plasmon resonance effect in noble metals at the nanoscale. These unique properties can play a vital role in enhancing the performance of photocatalytic CO2 conversion into solar fuels by engineering the nanostructures. In this review, we provide an overview of photocatalytic CO2 conversion and especially focus on nanostructured photocatalysts. The fundamental mechanism of photocatalytic CO2 conversion is discussed and recent progresses of low-dimensional photocatalysts for efficient conversion of CO2 into solar fuels are presented.

Hierarchical Nano/Micro-structured Surfaces with High Surface Area/Volume Ratios

2021 ◽  
pp. 1-36
Author(s):  
Ketki Lichade ◽  
Yizhou Jiang ◽  
Yayue Pan
Keyword(s):  
Surface Structure ◽  
Surface Area ◽  
Light Trapping ◽  
High Surface ◽  
High Surface Area ◽  
Three Dimensional ◽  
Structure Design ◽  
Surface Structures ◽  
Structured Surfaces ◽  
Design And Manufacture

Abstract Recently, many studies have investigated additive manufacturing of hierarchical surfaces with high surface area/volume (SA/V) ratios, and their performance has been characterized for applications in next-generation functional devices. Despite recent advances, it remains challenging to design and manufacture high SA/V ratio structures with desired functionalities. In this study, we established the complex correlations among the SA/V ratio, surface structure geometry, functionality, and manufacturability in the Two-Photon Polymerization (TPP) process. Inspired by numerous natural structures, we proposed a 3-level hierarchical structure design along with the mathematical modeling of the SA/V ratio. Geometric and manufacturing constraints were modeled to create well-defined three-dimensional hierarchically structured surfaces with a high accuracy. A process flowchart was developed to design the proposed surface structures to achieve the target functionality, SA/V ratio, and geometric accuracy. Surfaces with varied SA/V ratios and hierarchy levels were designed and printed. The wettability and antireflection properties of the fabricated surfaces were characterized. It was observed that the wetting and antireflection properties of the 3-level design could be easily tailored by adjusting the design parameter settings and hierarchy levels. Furthermore, the proposed surface structure could change a naturally-hydrophilic surface to near-superhydrophobic. Geometrical light trapping effects were enabled and the antireflection property could be significantly enhanced (>80% less reflection) by the proposed hierarchical surface structures. Experimental results implied the great potential of the proposed surface structures for various applications such as microfluidics, optics, energy, and interfaces.

scholarly journals Aerosol synthesis of thermally stable porous noble metals and alloys by using bi-functional templates

2020 ◽  
Vol 7 (2) ◽  
pp. 541-550 ◽  
Author(s):  
Mateusz Odziomek ◽  
Mounib Bahri ◽  
Cedric Boissiere ◽  
Clement Sanchez ◽  
Benedikt Lassalle-Kaiser ◽  
...  
Keyword(s):  
Noble Metal ◽  
Noble Metals ◽  
High Surface ◽  
Metals And Alloys ◽  
Metal Nanostructures ◽  
Thermally Stable ◽  
Surface Areas ◽  
Large Pore ◽  
Aerosol Synthesis ◽  
Noble Metal Nanostructures

Porous noble metal nanostructures providing high surface areas and large pore volumes are attractive for numerous applications, especially catalysis.

Enhanced visible-light photocatalytic hydrogen production activity of three-dimensional mesoporous p-CuS/n-CdS nanocrystal assemblies

2017 ◽  
Vol 4 (3) ◽  
pp. 433-441 ◽  
Author(s):  
Ioannis Vamvasakis ◽  
Adelais Trapali ◽  
Jianwei Miao ◽  
Bin Liu ◽  
Gerasimos S. Armatas
Keyword(s):  
Hydrogen Production ◽  
Visible Light ◽  
High Performance ◽  
Hydrogen Generation ◽  
High Surface ◽  
Three Dimensional ◽  
Surface Areas ◽  
Photocatalytic Hydrogen Generation ◽  
Production Activity ◽  
Visible Light Photocatalytic

Mesoporous assemblies of p-CuS/n-CdS nanocrystal junctions with high surface areas and uniform pores demonstrate a high performance and stability in photocatalytic hydrogen generation from water using visible light.

scholarly journals Hierarchical 3D ZnO nanowire structures via fast anodization of zinc

2015 ◽  
Vol 3 (34) ◽  
pp. 17569-17577 ◽  
Author(s):  
D. O. Miles ◽  
P. J. Cameron ◽  
D. Mattia
Keyword(s):  
Growth Rates ◽  
High Surface ◽  
Three Dimensional ◽  
Electrochemical Anodization ◽  
Nanowire Growth ◽  
Controlled Synthesis ◽  
Zno Nanowire ◽  
One Dimensional ◽  
Ambient Temperatures ◽  
Surface Areas

The rapid and controlled synthesis of three-dimensional hierarchical ZnO nanowires using electrochemical anodization is reported. The stages of nanowire growth are identified and growth rates are optimised to in excess of 3 μm min−1 at ambient temperatures. The structures produced combine high surface areas with the benefits of one-dimensional nanowires and have potential application in photocatalysis, photovoltaics and sensing.

A theoretical morphologic analysis of convergently evolved erect helical colony form in the Bryozoa

Paleobiology ◽  
2000 ◽  
Vol 26 (4) ◽  
pp. 556-577 ◽  
Author(s):  
George R. McGhee ◽  
Frank K. McKinney
Keyword(s):  
Surface Area ◽  
Dimensional Space ◽  
High Surface ◽  
High Surface Area ◽  
Three Dimensional ◽  
Filter Feeding ◽  
Colony Form ◽  
Surface Areas ◽  
Morphologic Analysis ◽  
Intermediate Surface

Exploration of the theoretical morphospace of erect helical colony form in Bryozoa, created by McKinney and Raup (1982), reveals that only a small volume of the three-dimensional space of hypothetical form is occupied by actual colonies of the Paleozoic fenestrates (Class Stenolaemata) Archimedes and Helicopora, helical species of the cheilostome (Class Gymnolaemata) Bugula, and the cyclostome (Class Stenolaemata) Crisidmonea archimediformis. Actual helical-colony bryozoans are not found in regions of the morphospace characterized by colony geometries that possess the largest surface areas of filtration sheet. Examination of computer-simulated colonies in the theoretical morphospace reveals that, although possessing high surface areas, colonies in the empty region of high-surface-area morphospace possess other aspects of geometry that are unrealistic as filter-feeding geometries: the filtration-sheet whorls are held at small acute angles to the central colony axis and are deeply nested within one another, both of which are disadvantageous conditions for the system of filter feeding used by the extant cheilostome Bugula, and presumably by extinct helical-colony bryozoans as well.Even though actual bryozoans are found only in the low to intermediate surface-area regions of the theoretical morphospace, surface area of filtration sheet is a major determinant of form in these helical colonies, as is evidenced by a negative correlation in values of the parameters BWANG and ELEV exhibited by the colony data. Minimum values of BWANG are even further constrained by the apparent need of the Archimedes colonies to maintain filtration-sheet branching densities within the range of 20 to 50.

Fabrication and enhanced light-trapping properties of three-dimensional silicon nanostructures for photovoltaic applications

2014 ◽  
Vol 86 (5) ◽  
pp. 557-573 ◽  
Author(s):  
Fei Xiu ◽  
Hao Lin ◽  
Ming Fang ◽  
Guofa Dong ◽  
Senpo Yip ◽  
...  
Keyword(s):  
Solar Cells ◽  
Light Trapping ◽  
High Surface ◽  
Photovoltaic Performance ◽  
Three Dimensional ◽  
Surface Recombination ◽  
Silicon Nanostructures ◽  
Photovoltaic Properties ◽  
Photovoltaic Applications ◽  
Carrier Collection

AbstractIn order to make photovoltaics an economically viable energy solution, next-generation solar cells with higher energy conversion efficiencies and lower costs are urgently desired. Among many possible solutions, three-dimensional (3D) silicon nanostructures with excellent light-trapping properties are one of the promising candidates and have recently attracted considerable attention for cost-effective photovoltaic applications. This is because their enhanced light-trapping characteristics and high carrier collection efficiencies can enable the use of cheaper and thinner silicon materials. In this review, recent developments in the controllable fabrication of 3D silicon nanostructures are summarized, followed by the investigation of optical properties on a number of different nanostructures, including nanowires, nanopillars, nanocones, nanopencils, and nanopyramids, etc. Even though nanostructures with radial p-n junction demonstrate excellent photon management properties and enhanced photo-carrier collection efficiencies, the photovoltaic performance of nanostructure-based solar cells is still significantly limited due to the high surface recombination effect, which is induced by high-density surface defects as well as the large surface area in high-aspect-ratio nanostructures. In this regard, various approaches in reducing the surface recombination are discussed and an overall geometrical consideration of both light-trapping and recombination effects to yield the best photovoltaic properties are emphasized.

scholarly journals Electrostatic Field Enhanced Photocatalytic CO2 Conversion on BiVO4 Nanowires

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Shuai Yue ◽  
Lu Chen ◽  
Manke Zhang ◽  
Zhe Liu ◽  
Tao Chen ◽  
...  
Keyword(s):  
Electrostatic Field ◽  
Photocatalytic Performance ◽  
Energy Conversion Efficiency ◽  
Model Structure ◽  
Co2 Conversion ◽  
Surface Absorption ◽  
Recombination Loss ◽  
Reduction Efficiency ◽  
Photocatalytic Co2 Conversion ◽  
Enhanced Surface

AbstractThe recombination loss of photo-carriers in photocatalytic systems fatally determines the energy conversion efficiency of photocatalysts. In this work, an electrostatic field was used to inhibit the recombination of photo-carriers in photocatalysts by separating photo-holes and photo-electrons in space. As a model structure, (010) facet-exposed BiVO4 nanowires were grown on PDMS-insulated piezo-substrate of piezoelectric transducer (PZT). The PZT substrate will generate an electrostatic field under a certain stress, and the photocatalytic behavior of BiVO4 nanowires is influenced by the electrostatic field. Our results showed that the photocatalytic performance of the BiVO4 nanowires in CO2 reduction in the negative electrostatic field is enhanced to 5.5-fold of that without electrostatic field. Moreover, the concentration of methane in the products was raised from 29% to 64%. The enhanced CO2 reduction efficiency is mainly attributed to the inhibited recombination loss of photo-carriers in the BiVO4 nanowires. The increased energy of photo-carriers and the enhanced surface absorption to polar molecules, which are CO in this case, were also play important roles in improving the photocatalytic activity of the photocatalyst and product selectivity. This work proposed an effective strategy to improve photo-carriers separation/transfer dynamics in the photocatalytic systems, which will also be a favorable reference for photovoltaic and photodetecting devices.

Z-scheme Photocatalytic CO2 Conversion on Three-Dimensional BiVO4/Carbon-Coated Cu2O Nanowire Arrays under Visible Light

ACS Catalysis ◽  
2018 ◽  
Vol 8 (5) ◽  
pp. 4170-4177 ◽  
Author(s):  
Chansol Kim ◽  
Kyeong Min Cho ◽  
Ahmed Al-Saggaf ◽  
Issam Gereige ◽  
Hee-Tae Jung
Keyword(s):  
Visible Light ◽  
Three Dimensional ◽  
Nanowire Arrays ◽  
Co2 Conversion ◽  
Carbon Coated ◽  
Photocatalytic Co2 Conversion
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