Search query: improve the performance of semiconductor photocatalyst

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abstract: Abstract MOF 5 is an emerging semiconductor material with a great potential in photocatalytic wastewater treatment. However, its inherent deficiencies, such as the narrow range of photo response, the fast recombination of photoinduced carriers and the unstable structure, largely limit its further application. In this work, super biocompatible N doped carbon quantum dots (N CQD) derived from the green precursor, coconut shells, were in situ grown on MOF 5 via a facile solvothermal method to construction of 0D/3D N CQD/MOF 5 photocatalyst with an enhanced photoreduction ability. A sustainable and pollution free preparation process of N CQD/MOF 5 photocatalyst was delivered and biomass waste resource was effectively utilized via this method. This well designed photocatalyst with the optimized 1% N CQD loading presented a considerable photoreduction rate of Cr (VI) which was 2.5 times higher that of pure MOF 5. It also possessed a strong structural stability and reusability even after multiple tests. The boosting photocatalysis activity could be attributed to the doping of N CQD, who not only act as an electron acceptor to separate the photoexcited electrons and holes effectively, but also play a vital role as a photosensitizer to improve the visible light absorption. Furthermore, the influence of activation methods on the photocatalytic activity of MOF 5 were also investigated theoretically. For the purpose of clarifying the potentially photocatalytic mechanism of N CQD/MOF 5 in photoreduction Cr (VI) a series of tests involving photoelectrical characterizations and fluorescence spectroscopy were executed. Therefore, this study provides an innovative photocatalytic system for an enhanced photoreduction performance of Cr (VI) of MOF 5.
author_names: Xiang Qin

Tao Qiang

Lu Chen

Shaoting Wang
title: Construction of 3D N CQD/MOF 5 photocatalyst to improve the photocatalytic performance of MOF 5 by changing the electron transfer path
year: 2021

abstract: Air and water pollution have become a significant environmental problem all over the world. Recently, an advanced oxidation process emerging to solve these problems has been based on the usage of abundant sunlight for the complete mineralization of toxic pollutants in the air and water. Although TiO2 semiconductor photocatalysts attract considerable attention owing to its high oxidizing property under ultraviolet (UV) light, the UV light occupies only 5% of solar energy. In the present study, the upconversion nanoparticles of NaYF4:Yb,Ho and NaYF4:Yb,Tm which convert the near infrared (NIR) to visible light and UV region are used to combine with anatase TiO2 aerogel with large specific surface area via a green and easy chemical process.
author_names: Fu Li

Yoshitaka Kitamoto
title: Fabrication of UCNPs/TiO2 aerogel photocatalyst to improve photocatalytic performance
year: 2017

abstract: Abstract Semiconductor photocatalytic technology has become a new green way to control NOX emissions. In order to remove NOX effectively, a multi stage electron transport channel was constructed to improve the photocatalytic activity of graphitic carbon nitride (g C3N4) which was realized by doping Fe ions and compounding with reductive graphene oxide (rGO) simultaneously. The results of NO removal test showed that the as prepared rGO/Fe doped g C3N4 visible light driven composite photocatalyst exhibited significantly improved photocatalytic activity, and the optimum mass ratio of rGO to Fe was 2:3. This was attributed to the positive synergistic effect of Fe and rGO and the formation of a multi stage electron transport channel between rGO and protonated Fe doped g C3N4 (Fe C3N4) which further accelerated the separation and transfer of photo induced carriers, broadened the visible light response range and enhanced the light absorption intensity. This work develops a g C3N4 based visible light photocatalyst that can effectively remove NO and provides a new perspective for the modification of photocatalyst.
author_names: Xiaoyu Yang

Xuejuan Cao

Boming Tang

Bailin Shan

Mei Deng

Yugui Liu
title: rGO/Fe doped g C3N4 visible light driven photocatalyst with improved NO removal performance
venue: Journal of Photochemistry and Photobiology A: Chemistry
year: 2019

abstract: Abstract Semiconductor driven photocatalysis has galvanized great attention as it holds tremendous promise to address the worldwide environmental and energy issues. Photocatalysis, in which photons are used for redox reactions, is at the central point to achieve this goal. The heterogeneous photocatalysts with integrated functional nano composites can combine the advantages of different nano composites to overcome the drawbacks of single nano photocatalysts. Coupling of TiO2 with narrow band gap semiconductor nanocomposites has been a strategy used by researchers to obtain visible light active photocatalysts. In this work, graphene has been used to improve the performance of photocatalysts based on its great charge conductivity as well as other exciting properties. The edge effect has been removed by introducing the 2D graphene into circular rolls inserted in the 65 140 nm TiO2, TiO2 CuO (TC) and TiO2/ZnO/Bi2O3 (TZB) nanofibers (NFs) and free electrons can only travel in specific direction along the axis of the TiO2, TiO2 CuO (TC) and TiO2/ZnO/Bi2O3 (TZB) (NFs) The resulting (NFs) has less band gap energy that facilitates harvesting of the visible light spectrum. The graphene incorporation helps to harvest more energy from the entire UV vis spectrum and almost doubled the surface area of the (NFs) when maximum amount of graphene is embedded into the (NFs) The T Gr, TC Gr and TZB Gr photocatalyst, after optimized with as much as 32.18% 16.87% and 26.5% respectively by mass of graphene in the (NFs) has superior photoactivity in degradation of formaldehyde under solar irradiation. The kinetics and fundamental mechanism of formaldehyde degradation are also addressed. The graphene insertion controls the work function of photocatalysts, which is critical for photocatalytic reactions.
author_names: Muzafar A Kanjwal

Wallace Woon-Fong Leung
title: Titanium based composite graphene nanofibers as high performance photocatalyst for formaldehyde gas purification
venue: Ceramics International
year: 2019

abstract: Abstract A facile method was developed to synthesize a series of hollow mesoporous SiO 2 BiOCl@PANI@Pd (HBPP) photocatalysts with super adsorption performance, plasmonic effect and fast interfacial charge migration. The samples were characterized by XRD, FETEM, FT IR, XPS, DRS, etc. Photocatalytic degradation of methyl orange (MO) by HBPP composites was investigated. Results showed that the photocatalytic property of HBPP composite was superior to that of hollow mesoporous SiO 2 BiOCl@PANI (HBP) composite under visible light irradiation, and the HBPP 5wt% photocatalyst synthesized under 140 degC exhibits the highest photocatalytic activity. In this photocatalysis system, the orderly mesoporous opening structure of the hollow mesoporous SiO 2 sphere could effectively facilitate the transfer of reactant molecules, and the existence of the internal cavities would effectively prolong the action time of the irradiated light for the multiple reflections. Moreover, the formation of interacted interfaces between the semiconductor BiOCl and conducting polymer (polyaniline) could effectively improve the separation of the photogenerated electron hole pairs, and the palladium nanoparticles (Pd NPs) with strong localized surface plasmon resonance (LSPR) absorption band in the near UV region could effectively induce the generation of the photoexcited electron hole pairs in BiOCl, thus the as obtained photocatalyst exhibits superior photocatalytic activity under visible light irradiation. The work may set foundation for application of the new photocatalyst of HBPP based LSPR and make an important step forward remedying environmental pollution.
author_names: Yi Tian

Wei Li

Chenhui Zhao

Yufei Wang

Baoliang Zhang

Qiuyu Zhang
title: Fabrication of hollow mesoporous SiO2 BiOCl@PANI@Pd photocatalysts to improve the photocatalytic performance under visible light
year: 2017

abstract: In this paper, an all solid Z scheme Ag3PO4/GO/NCD photocatalyst has been prepared through anchoring nitrogen doped carbon dots (NCDs) on the Ag3PO4/GO (GO graphene oxide) composite. The Ag3PO4/GO/NCD photocatalyst exhibits excellent photocatalytic activity for the degradation of organic pollutants, methylene blue (MB) rhodamine B (RhB) and phenol, under visible light irradiation. The pollutants MB (10 mg L 1) RhB (10 mg L 1) and phenol (50 mg L 1) could be efficiently degraded within 2.5 min, 5 min and 120 min, respectively, which are much better than that over Ag3PO4 and Ag3PO4/GO, indicating that the introduction of NCDs can further improve the photocatalytic activity of Ag3PO4/GO. Moreover, after four photocatalytic cycles, the photocatalytic activity of Ag3PO4/GO/NCDs shows only a slight decrease, demonstrating high photocatalytic stability. It is revealed that GO in the photocatalyst acts as a semiconductor and forms a Z scheme heterojunction with Ag3PO4, while NCDs improve the oxygen activation, enhance the light harvesting capacity and serve as the reaction sites during the photocatalytic process. This study highlights the potential application of highly efficient NCD modified photocatalysts in waste water purification.
author_names: Xuli Miao

Xiaoyang Yue

Xiaoping Shen

Zhenyuan Ji

Hu Zhou

Guoxing Zhu

Jiheng Wang

Lirong Kong

Miaomiao Liu

Chunsen Song
title: Nitrogen doped carbon dot modified Ag3PO4/GO photocatalyst with excellent visible light driven photocatalytic performance and mechanism insight
year: 2018

abstract: Absorption of visible light and separation of photogenerated charges are two primary pathways to improve the photocurrent performance of semiconductor photoelectrodes. Here, we present a unique design of tricomponent photocatalyst comprising of TiO2 multileg nanotubes (MLNTs) reduced graphene oxide (rGO) and CdS nanoparticles. The tricomponent photocatalyst shows a significant red shift in the optical absorption 2.2 eV) compared to that of bare TiO2 MLNTs 3.2 eV).The availability of the both inner and outer surfaces areas of MLNTs, visible light absorption of CdS, and charge separating behavior of reduced graphene oxide layers contribute coherently to yield a photocurrent density of ~11 mA/cm2 0 V vs. Ag/Cl (100 mW/cm2, AM 1.5 G) Such a high PEC performance from TiO2/rGO/CdS photoelectrode system has been analyzed using diffused reflectance (DRS) and electrochemical impedance (EIS) spectroscopy techniques. The efficient generation of charge carriers under light irradiation and easy separation because of favourable band alignment are attributed to the high photoelectrochemical current density in these tricomponent photocatalyst system.
author_names: Rambabu Yalavarthi

Swati Dhua

Manu Jaiswal

Somnath Chanda Roy
title: High photoelectrochemical performance of reduced graphene oxide wrapped, CdS functionalized, TiO2 multi leg nanotubes.
venue: Nanotechnology
year: 2020

abstract: Abstract Among the different alternatives to generate hydrogen, photocatalysis can play an important role since it is based on the use of solar radiation and a suitable semiconductor. Starting from the most commonly researched TiO2 catalyst, many efforts have been devoted to improve its efficacy. This work, based on the potential of reduced graphene oxide (rGO) to carry charges and platinum nanoparticles to act as efficient traps for photogenerated electrons, assesses the performance of synthesized binary and ternary photocatalysts (TiO2/rGO, TiO2/Pt and TiO2/rGO/Pt) for hydrogen generation. The addition of rGO to TiO2 almost duplicates (1.95 factor) the hydrogen production rate compared to bare TiO2. Moreover, the binary TiO2/Pt photocatalyst reported the best performance, with an increase in the hydrogen production rate by a factor of 15.26 compared to TiO2. However, the ternary catalyst performed worse than the binary TiO2/Pt probably due to the use of non optimized co catalyst ratios. Since the addition of rGO reduces the cost of the catalyst, the trade off between the catalyst performance and cost is worth of future research.
author_names: Maria J Rivero

Olalla Iglesias

Paula Ribao

Inmaculada Ortiz
title: Kinetic performance of TiO2/Pt/reduced graphene oxide composites in the photocatalytic hydrogen production
year: 2019

abstract: Metal complex/semiconductor hybrids have attracted attention as photocatalysts for visible light CO2 reduction, and electron transfer from the metal complex to the semiconductor is critically important to improve the performance. Here rutile TiO2 nanoparticles having 5 10 nm in size were employed as modifiers to improve interfacial charge transfer between semiconducting carbon nitride nanosheets (NS C3N4) and a supramolecular Ru(II) Re(I) binuclear complex (RuRe) The RuRe/TiO2/NS C3N4 hybrid was capable of photocatalyzing CO2 reduction into CO with high selectivity under visible light (l 400 nm) outperforming an analogue without TiO2 by a factor of 4, in terms of both CO formation rate and turnover number (TON) The enhanced photocatalytic activity was attributed primarily to prolonged lifetime of free and/or shallowly trapped electrons generated in TiO2/NS C3N4 under visible light irradiation, as revealed by transient absorption spectroscopy. Experimental results also indicated that the TiO2 modifier served as a good adsorption site for RuRe, which resulted in the suppression of undesirable desorption of the complex, thereby contributing to the improved photocatalytic performance. This study presents the first successful example of interfacial manipulation in a metal complex/semiconductor hybrid photocatalyst for improved visible light CO2 reduction to produce CO.
author_names: Keisuke Wada

Chandana Sampath Kumara Ranasinghe

Ryo Kuriki

Akira Yamakata

Osamu Ishitani

Kazuhiko Maeda
title: Interfacial Manipulation by Rutile TiO2 Nanoparticles to Boost CO2 Reduction into CO on a Metal Complex/Semiconductor Hybrid Photocatalyst.
venue: ACS applied materials interfaces
year: 2017

abstract: The coupling of carbon nanomaterials with semiconductor photocatalysts is a promising route to improve their photocatalytic performance. Herein, density functional theory was used to investigate the electronic structure, charge transfer, photocatalytic activity, and stability in a series of hybrid fullerene (C20, Li@C20, C26, Li@C26)/Ag3PO4(100) composites. When a Li atom is incorporated in fullerene, the adsorption energies significantly increase, although the change of interface distance is negligibly small due to the weak interface interaction. The charge transfer between constituents decreases with the C atom number of fullerene. Compared to pure Ag3PO4, the band gap of the composites is smaller, which enhances the visible light absorption and photoinduced electron transfer. Most importantly, a type II, staggered band alignment could be obtained in the C26 Ag3PO4(Li@C26 Ag3PO4) interface, leading to significantly reduced charge recombination and thus enhanced photocatalytic activity. These results reveal that fullerene modification would be an effective strategy to improve the photocatalytic performance of Ag3PO4 semiconductor photocatalysts.
author_names: Caiping Luo

Wei-Qing Huang

Liang Xu

Yingbin Yang

Xiaofang Li

Wangyu Hu

Ping Peng

Gui-Fang Huang
title: Enhanced photocatalytic performance of an Ag3PO4 photocatalyst via fullerene modification: first principles study.
venue: Physical chemistry chemical physics PCCP
year: 2016