Query: photocatalyst  metal

Candidate papers:

abstract: Abstract Metalloporphyrinic metal organic framework (PCN 222) is a promising photocatalytic material due to its large surface area and 1D channel, exceptional stability, high visible light capture capability, and semiconductor properties. Herein, we constructed a highly efficient visible light driven type II heterojunction photocatalyst PCN 222 PW12/TiO2 by one step solvothermal method. The 5 wt% PCN 222 PW12/TiO2 showed the superior photocatalytic properties for degrading rhodamine B (RhB) and Ofloxacin, which are 10.69 and 10.48 times higher than pure TiO2 under same conditions. The excellent photocatalytic performance of PCN 222 PW12/TiO2 ternary composite material was attributed to the improved adsorption capacity of organic pollutants, optical absorption in the entire visible light region, and highly efficient separation of photoinduced carriers. Besides, we found that h+ O2 and OH are the main active elements in the photocatalytic degradation process. This will back up the higher photocatalytic activity of PCN 222 PW12/TiO2 compared with pure TiO2. The photocatalytic efficiency of composite maintained a similar level of photoactivity after four times recovery, which showed excellent stability and recyclability of PCN 222 PW12/TiO2. This work provides new insights into the fabrication porphyrin MOF composite materials with high photocatalytic efficiency for environmental remediation.
author_names: Lanjie Li

Xinming Yu

Lei Xu

Ya-hui Zhao
title: Fabrication of a novel type visible light driven heterojunction photocatalyst: Metal porphyrinic metal organic framework coupled with PW12/TiO2
year: 2020

abstract: A visible light mediated direct C H arylation of quinoxalin 2(1H) ones with aryl acyl peroxides has been developed. The reaction proceeds smoothly through a radical process in the absence of photocatalyst, additive and metal catalyst, providing the corresponding products in moderate to good yields. This methodology opens a simple and green access to 3 arylquinoxalin 2(1H) ones.
author_names: Jun Xu

Hongdou Zhang

Jianmin Zhao

Zhigang Ni

Pengfei Zhang

Bing-Feng Shi

Wan-mei Li
title: Photocatalyst metal and additive free, direct C H arylation of quinoxalin 2(1H) ones with aryl acyl peroxides induced by visible light
year: 2020

abstract: An enduring catalyst built from carbon Splitting water into its constituent elements, hydrogen and oxygen, generally requires the assistance of metal catalysts. Liu et al. now show that a metal free hybrid material composed of carbon and nitrogen can promote this reaction all on its own, with the help of some visible light. The photocatalyst combines one material (C3N4) known to split water into hydrogen and peroxide with a second material (CDot) that breaks the peroxide down before it can damage the first. The robust stability of this hybrid bodes well for practical implementation of optimized analogs in solar energy storage schemes. Science, this issue p. 970 A hybrid nanomaterial comprising carbon and nitrogen proves a robust catalyst for light driven water splitting into H2 and O2. The use of solar energy to produce molecular hydrogen and oxygen (H2 and O2) from overall water splitting is a promising means of renewable energy storage. In the past 40 years, various inorganic and organic systems have been developed as photocatalysts for water splitting driven by visible light. These photocatalysts, however, still suffer from low quantum efficiency and/or poor stability. We report the design and fabrication of a metal free carbon nanodot carbon nitride (C3N4) nanocomposite and demonstrate its impressive performance for photocatalytic solar water splitting. We measured quantum efficiencies of 16% for wavelength l 420 20 nanometers, 6.29% for l 580 15 nanometers, and 4.42% for l 600 10 nanometers, and determined an overall solar energy conversion efficiency of 2.0% The catalyst comprises low cost, Earth abundant, environmentally friendly materials and shows excellent stability.
author_names: Juan Liu

Yang Liu

Naiyun Liu

Yuzhi Han

Xing Zhang

Hui Huang

Yeshayahu Lifshitz

Shui-Tong Lee

Jun Zhong

Zhenhui Kang
title: Metal free efficient photocatalyst for stable visible water splitting via a two electron pathway
venue: Science
year: 2015

abstract: The photo driven direct C C/C N bond formation initiated by electron donor acceptor (EDA) complexes for the synthesis of indoles has been accomplished via [3 2] annulations of secondary arylamines with alkynes using IC4F9 as oxidants in the absent of any photocatalysts and metals. This green transformation exhibits the advantages of operational simplicity, good functional tolerances and mild reaction conditions. The in situ generated EDA complexes derived from arylamines with alkynes were characterized by UV vis absorption spectrometry and NMR titration experiments.
author_names: Wei Guo

Kailiang Tao

Zhen Biao Xie

Liuhuan Cai

Mingming Zhao

Wen-Han Tan

Gongpin Liu

Weijie Mei

Ling Deng

Xiao-lin Fan

Lvyin Zheng
title: Photo Driven Photocatalyst /Metal Free Direct C C/C N Bond Formation: Synthesis of Indoles via EDA Complexes.
venue: The Journal of organic chemistry
year: 2019

abstract: Cross contamination of foods with pathogenic microorganisms such as bacteria, viruses, and parasites may occur at any point in the farm to fork continuum. Food contact and nonfood contact surfaces are the most frequent source of microbial cross contamination. In the wake of new and emerging food safety challenges, including antibiotic resistant human pathogens, conventional sanitation and disinfection practices may not be sufficient to ensure safe food processing, proper preparation, and also not be environmentally friendly. Nanotechnology enabled novel food safety interventions have a great potential to mitigate the risk of microbial cross contamination in the food chain. Especially engineered nanoparticles (ENPs) are increasingly finding novel applications as antimicrobial agents. Among various ENPs, photocatalyst metal oxides have shown great promise as effective nontargeted disinfectants over a wide range of microorganisms. The present review provides an overview of antimicrobial properties of various photocatalyst metal oxides and their potential applications as surface coatings. Further, this review discusses the most common approaches to developing antimicrobial coatings, methods to characterize, test, and evaluate antimicrobial efficacy as well as the physical stability of the coatings. Finally, regulations and challenges concerning the use of these novel photocatalytic antimicrobial coatings are also discussed.
author_names: Veerachandra K Yemmireddy

Yen-Con Hung
title: Using Photocatalyst Metal Oxides as Antimicrobial Surface Coatings to Ensure Food Safety Opportunities and Challenges.
venue: Comprehensive reviews in food science and food safety
year: 2017

abstract: Abstract Photocatalysis is a promising technology that can convert solar energy into chemical energy. However, developing photocatalyst that could be put into the practical application remains a big challenge worldwide. In the recent years, an emerging type of core shell/core shell like composites, in which the metal or metal containing nanoparticles (M/MC NPs) cores are encapsulated by the metal organic frameworks (MOFs) shells, have attracted increasing attention in photocatalysis. These M/MC NP@MOF nanocomposites are believed to be one of the most effective and convenient ways to achieve property synergies of MOFs and M/MC NPs. Even though this field is currently in its infancy, the promising results obtained have validated the potential use of M/MC NP@MOF nanocomposites in practical applications. In this review, the fundamental mechanisms of photocatalysis were briefly introduced. The synthesis of M/MC NP@MOF nanocomposites and related photocatalytic applications (such as photocatalytic hydrogen generation and Cr(VI) reduction) are summarized and exemplified. Special emphasis is given to the synergistic effects between the MOFs shell and NPs core that result in an enhanced performance in heterogeneous photocatalysis. Finally, the unsolved problems of M/MC NP@MOF nanocatalysts are discussed and the future development prospects are proposed.
author_names: Yang Liu

Zhifeng Liu

Danlian Huang

Min Cheng

Guangming Zeng

Cui Lai

Chen Zhang

Chengyun Zhou

Wenjun Wang

Danni Jiang

Han Wang

Binbin Shao
title: Metal or metal containing nanoparticle@MOF nanocomposites as a promising type of photocatalyst
venue: Coordination Chemistry Reviews
year: 2019

abstract: Abstract Visible light active, heterogeneous, and organic photocatalysts exhibit a more sustainable and environmentally friendly alternative to classical metal based catalysts. Two dimensional covalent organic frameworks (2D COFs) with permanent porosity, columnar p arrays and excellent stability, that can become an excellent platform for heterogeneous photocatalysis of organic transformations. Here we report a predesigned imine based COF with electron donor and acceptor structure. And new framework possesses large surface area, high crystallinity, outstanding stability and broad absorption range in the visible light region as well as good photoelectric response characteristics. Importantly, it was found to be a highly effective heterogeneous photocatalyst for reductive dehalogenation of phenacyl bromide derivatives and a alkylation of aldehydes under irradiation of visible light. In addition, the COF gave good recyclability and could be reused after a simple separation manipulation. The current present still reveals a great prospect for 2D COFs as metal free, heterogeneous photocatalysts for organic transformations.
author_names: Ziping Li

Yongfeng Zhi

Pengpeng Shao

Hong Xia

Guosheng Li

Xiao Feng

Xiong Chen

Zhan Shi

Xiaoming Liu
title: Covalent organic framework as an efficient, metal free, heterogeneous photocatalyst for organic transformations under visible light
venue: Applied Catalysis B: Environmental
year: 2019

abstract: Conversion of naturally abundant dinitrogen (N2) to ammonia (NH3) is one of the most attractive and challenging topics in chemistry. Current studies mainly focus on electrocatalytic nitrogen reduction reaction (NRR) using metal based electrocatalysts, while metal free and solar driven photocatalysts have been rarely explored. Here, on basis of the "s donation p* backdonation" concept, single B atom supported on holey g CN (B@g CN) can serve as metal free photocatalyst for highly efficient N2 fixation and reduction under visible and even infrared spectra. Our results reveal that N2 can be efficiently activated and reduced to NH3 with extremely low overpotential of 0.15 V and activation barrier of 0.61 eV, lower than most of metal based NRR catalysts, thereby guaranteeing the high energy efficiency and fast kinetics of NRR. The inherent properties of B@g CN, such as centralized spin polarization on the B atom, efficient prohibition of competitive hydrogen evolution reaction (HER) and reduced exciton binding energy, are responsible for the high selectivity and Faradic efficiency for NRR under ambient conditions. Moreover, for the first time, we theoretically disclose that the external potential provided by photogenerated electrons for NRR/HER endowing B@g CN spontaneous NRR and inaccessible HER. This work may provide a promising lead for designing efficient and robust metal free single atom catalysts toward photocatalytic NRR under visible/infrared spectrum.
author_names: Xingshuai Lv

Wei Wei

Fengping Li

Baibiao Huang

Ying Dai
title: Metal Free B@g CN: Visible/Infrared Light Driven Single Atom Photocatalyst Enables Spontaneous Dinitrogen Reduction to Ammonia.
venue: Nano letters
year: 2019

abstract: Summary Solar water disinfection catalyzed by metal free photocatalyst has emerged as a promising approach for clean water production. By using the edge functionalized graphitic carbon nitride (g C3N4) as photocatalytic disinfectants, we find that the pathogen rich water can be rapidly purified in 30 min with a disinfection efficiency of over 99.9999% under visible light irradiation, which meets the requirement for drinking water. The edge functionalized g C3N4 shows a first order disinfection rate that is five times higher than the previously reported best metal free photocatalyst but only consumes 1/10 of the catalyst. The catalytic activity is also comparable to that of the best metal based photocatalyst. Results of the highest occupied molecular orbitals and Mulliken charge distribution reveal that the exposed COOH and C=O groups at the edges of g C3N4 nanosheets not only significantly promote charge separation but also induce the upward bending of the surface band, facilitating the generation of hydrogen peroxide.
author_names: Zhenyuan Teng

Nailiang Yang

Hongying Lv

Sicong Wang

Maozhi Hu

Chengyin Wang

Dan Wang

Guoxiu Wang
title: Edge Functionalized g C3N4 Nanosheets as a Highly Efficient Metal free Photocatalyst for Safe Drinking Water
venue: Chem
year: 2019

abstract: A full spectrum (300 700 nm) responsive porphyrin supramolecular photocatalyst with a theoretical solar spectrum efficiency of 44.4% is successfully constructed. For the first time, hydrogen and oxygen evolution (40.8 and 36.1 umol g 1 h 1 is demonstrated by a porphyrin photocatalyst without the addition of any cocatalysts. The strong oxidizing performance also presents an efficient photodegradation activity that is more than ten times higher than that of g C3 N4 for the photodegradation of phenol. The high photocatalytic reduction and oxidation activity arises from a strong built in electric field due to molecular dipoles of electron trapping groups and the nanocrystalline structure of the supramolecular photocatalyst. The appropriate band structure of the supramolecular photocatalyst adjusted via the highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels of the porphyrin gives rise to thermodynamic driving potential for H2 and O2 evolution under visible light irradiation. Controlling the energy band structure of photocatalysts via the ordered assembly of structure designed organic molecules could provide a novel approach for the design of organic photocatalysts in energy and environmental applications.
author_names: Zijian Zhang

Yongfa Zhu

Xianjie Chen

Hanjie Zhang

Jun Wang
title: A Full Spectrum Metal Free Porphyrin Supramolecular Photocatalyst for Dual Functions of Highly Efficient Hydrogen and Oxygen Evolution.
venue: Advanced materials
year: 2019