载银g-C3N4(Ⅰ)/g-C3N4(Ⅱ)同素异质结催化剂的制备及光催化固氮产氨性能

doi:10.11896/j.issn.1005-023X.2018.20.002

Abstract
Figure/Table
References
Related Citation (1)

Download:

Full Text ( PDF ) (4389KB)
Export: BibTeX | EndNote (RIS)

Abstract As a cocatalyst, silver can enhance the photoelectrons migration and has found wide application in a variety of photocatalytic reduction reactions such as water splitting hydrogen generation, CO₂ reduction, heavy metal ion reduction, etc. However, to the best of our knowledge, no unconcealed work has concerned N₂ photofixation by using Ag-loaded catalysts. Our present work aimed to prepare a series of Ag-loaded g-C₃N₄(Ⅰ)/g-C₃N₄(Ⅱ) isotype heterojunction catalysts differing in Ag content (Ag(x%)-CN, x=0.5,1,2,4) and estimate their N₂ photofixation performance. The means of XRD, TEM, UV-Vis, XPS, Raman, PL, EIS and photocurrent response were involved in the characterization. Our experiment confirmed the existence of silver on the catalyst surface as metal state, and revealed the acting mechanism of the loaded silver cocatalyst: the plasma effect of silver promotes the visible-light absorption so that the reaction system can produce more photogenerated electron-hole pairs, and on the other hand, the photoelectrons migration between g-C₃N₄ and Ag improves the electron-hole separation efficiency of the composite catalyst. The NH₄⁺ ge-neration rate of the Ag-loaded g-C₃N₄(Ⅰ)/g-C₃N₄(Ⅱ) isotype heterojunction composite catalyst was determined to be 1.36 mg·L^-1·h^-1·g^-1_cat with a dramatical increment compared to that of g-C₃N₄(Ⅰ)/g-C₃N₄(Ⅱ) without silver-loading (MU-CN,0.59 mg·L^-1·h^-1·g^-1_cat). This catalytic performance is equivalent to the Pt-loaded catalysts, and moreover, 4.9 or 3.4 times higher than g-C₃N₄prepared by exclusively using melamine or urea. In addition to nitrogen fixation, the Ag-loaded g-C₃N₄(Ⅰ)/g-C₃N₄(Ⅱ) isotype heterojunction catalysts also exhibited excellent catalytic performance in the reaction of photocatalytic reduction of oxygen to hydrogen peroxide.

Key words： graphitic carbon nitride (g-C₃N₄) silver loading noble metal isotype heterojunction N₂ photofixation

Published: 22 November 2018

CLC number:	O641
	O649

	Service
	E-mail this article
	Add to my bookshelf
	Add to citation manager
	E-mail Alert
	RSS
	Articles by authors
	WANG Hui
	LI Shijun
	WANG Mei
	PEI Yanbo
	HU Shaozheng

Cite this article:

WANG Hui,LI Shijun,WANG Mei, et al. Ag-loaded g-C₃N₄(Ⅰ)/g-C₃N₄(Ⅱ) Isotype Heterojunction Catalysts with an Application to Photocatalytic N₂ Fixation[J]. Materials Reports, 2018, 32(20): 3496-3503.

URL:

http://www.mater-rep.com/EN/10.11896/j.issn.1005-023X.2018.20.002 OR http://www.mater-rep.com/EN/Y2018/V32/I20/3496

1 Schrauzcr G N, Guth T D. Photocatalytic reactions. 1. Photolysis of water and photoreduction of nitrogen on titanium dioxide [J]. Journal of America Chemistry Society,1977,99(22):7189.
2 Hu S Z, Li F Y, Fan Z P, et al. Band gap-tunable potassium doped graphitic carbon nitride with enhanced mineralization ability [J]. Dalton Transactions,2015,44(3):1084.
3 Wang X C, Maeda K, Thomas A, et al. A metal-free polymeric photocatalyst for hydrogen production from water under visible light [J]. Nature Materials,2009,8(1):76.
4 Ansari M B, Jin H L, Parvin M N, et al. Mesoporous carbon nitride as a metal-free base catalyst in the microwave assisted Knoevenagel condensation of ethylcyanoacetate with aromatic aldehydes [J]. Catalysis Today,2012,185(1):211.
5 Hu S Z, Chen X, Li Q, et al. Fe³⁺ doping promoted N₂ photofi-xation ability of honeycombed graphitic carbon nitride: The experimental and density functional theory simulation analysis [J]. Applied Catalysis B: Environmental,2017,201(1):58.
6 Li H, Shang J, Ai Z H, et al. Efficient visible light nitrogen fixation with BiOBr nanosheets of oxygen vacancies on the exposed {001} facets [J]. Journal of America Chemistry Society,2015,137(19):6393.
7 Li S N, Dong G H, Hailili R, et al. Effective photocatalytic H₂O₂ production under visible light irradiation at g-C₃N₄ modulated by carbon vacancies [J]. Applied Catalysis B: Environmental,2016,190(5):26.
8 Rong X S, Qiu F X, Yan J, et al. Coupling with a narrow-band-gap semiconductor for enhancement of visible-light photocatalytic activity: Preparation of Bi₂S₃/g-C₃N₄ and application for degradation of RhB [J]. RSC Advance,2015,5(32):24944.
9 Liu H H, Chen D L, Wang Z Q, et al. Microwave-assisted molten-salt rapid synthesis of isotype triazine-/heptazine based g-C₃N₄ he-terojunctions with highly enhanced photocatalytic hydrogen evolution performance [J]. Applied Catalysis B: Environmental,2017,203(1):300.
10 Bai X J, Zong R L, Li C X, et al. Enhancement of visible photocatalytic activity via Ag@C₃N₄ core-shell plasmonic composite [J]. Applied Catalysis B: Environmental,2014,147(5):82.
11 Krejcíková S, Matejová L, Kocí K, et al. Preparation and characte-rization of Ag-doped crystalline titania for photocatalysis applications [J]. Applied Catalysis B: Environmental,2012,111-112(12):119.
12 Eskandarloo H, Badiei A, Behnajady M A, et al. Minimization of electrical energy consumption in the photocatalytic reduction of Cr (Ⅵ) by using immobilized Mg, Ag co-impregnated TiO₂ nanoparticles [J]. RSC Advance,2014,4(54):28587.
13 Ranjit K T, Varadarajan T K, Viswanathan B. Photocatalytic reduction of dinitrogen to ammonia over noble-metal-loaded TiO₂ [J]. Journal of Photochemistry and Photobiology A: Chemistry,1996,96(1-3):181.
14 Liao G Z, Chen S, Quan X, et al. Graphene oxide modified g-C₃N₄ hybrid with enhanced photocatalytic capability under visible light irradiation [J]. Journal of Materials Chemistry,2012,22(6):2721.
15 Sridharan K, Jang E, Park T J. Novel visible light active graphitic C₃N₄-TiO₂ composite photocatalyst: Synergistic synthesis, growth and photocatalytic treatment of hazardous pollutants[J].Applied Catalysis B: Environmental,2013,142-143(1):718.
16 Ge L, Han C C, Xiao X L, et al. Synthesis and characterization of composite visible light active photocatalysts MoS₂-g-C₃N₄ with enhanced hydrogen evolution activity [J]. International Journal of Hydrogen Energy,2013,38(17):6960.
17 Lu M L, Pei Z X, Weng S X, et al. Constructing atomic layer g-C₃N₄-CdS nanoheterojunctions with efficiently enhanced visible light photocatalytic activity [J]. Physical Chemistry Chemical Physics,2014,16(39):21280.
18 Yang M, Hu S Z, Li F Y, et al. The influence of preparation me-thod on the photocatalytic performance of g-C₃N₄/WO₃ composite photocatalyst [J]. Ceramics International,2014,40(8):11963.
19 Hu S Z, Ma L, Li F Y, et al. Construction of g-C₃N₄/S-g-C₃N₄ metal-free isotype heterojunctions with an enhanced charge driving force and their photocatalytic performance under anoxic conditions [J]. RSC Advance,2015,5(110):90750.
20 Wang J H, Chen Y L, Shen Y F, et al. Coupling polymorphic nanostructured carbon nitrides into an isotype heterojunction with boosted photocatalytic H₂ evolution [J]. Chemical Communications,2017,53(20):2978.
21 Dong F, Ni Z L, Li P D, et al. A general method for type Ⅰ and type Ⅱ g-C₃N₄/g-C₃N₄ metal-free isotype heterostructures with enhanced visible light photocatalysis [J]. New Journal of Chemistry,2015,39(6):4737.
22 Zhao W R, Zhang J, Zhu X, et al. Enhanced nitrogen photofixation on Fe-doped TiO₂ with highly exposed (101) facets in the presence of ethanol as scavenger [J]. Applied Catalysis B: Environmental,2014,144(1):468.
23 Dong F, Zhao Z W, Xiong T, et al. In situ construction of g-C₃N₄/g-C₃N₄ metal-free heterojunction for enhanced visible-light photocatalysis [J]. ACS Applied Materials&Interfaces,2013,5(21):11392.
24 Wang Y, Wang X C, Antonietti M. Polymeric graphitic carbon nitride as a heterogeneous organocatalyst: From photochemistry to multipurpose catalysis to sustainable chemistry [J]. Angewandte Chemie International Edition,2012,51(1):68.
25 Sakai H, Kanda T, Shibata H, et al. Preparation of highly dispersed core/shell-type titania nanocapsules containing a single Ag nanoparticle [J]. Journal of America Chemistry Society,2006,128(15):4944.
26 Sun Y J, Xiong T, Ni Z L, et al. Improving g-C₃N₄ photocatalysis for NO_x removal by Ag nanoparticles decoration [J]. Applied Surface Science,2015,358(15):356.
27 Ge L, Han C C, Liu J, et al. Enhanced visible light photocatalytic activity of novel polymeric g-C₃N₄ loaded with Ag nanoparticles [J]. Applied Catalysis A: General,2011,409-410(15):215.
28 Wang P, Huang B B, Qin X Y, et al. Ag@AgCl: A highly efficient and stable photocatalyst active under visible light [J]. Angewandte Chemie International Edition,2008,47(41):7931.
29 Ge L, Han C. Synthesis of MWNTs/g-C₃N₄ composite photocatalysts with efficient visible light photocatalytic hydrogen evolution activity [J]. Applied Catalysis B: Environmental,2012,117-118(1):268.
30 Lei W, Portehault D, Dimova R, et al. Boron carbon nitride nanostructures from salt melts: Tunable water-soluble phosphors [J]. Journal of America Chemistry Society,2011,133(18):7121.
31 Zhang Y W, Liu J H, Wu G, et al. Porous graphitic carbon nitride synthesized via direct polymerization of urea for efficient sunlight-driven photocatalytic hydrogen production [J]. Nanoscale,2012,4(17):5300.
32 Fu Y S, Huang T, Zhang L L, et al. Ag/g-C₃N₄ catalyst with superior catalytic performance for the degradation of dyes: A borohydride-generated superoxide radical approach [J]. Nanoscale,2015,7(32):13723.
33 Wang G X, Shen X P, Yao J, et al. Graphene nanosheets for enhanced lithium storage in lithium ion batteries [J]. Carbon,2009,47(8):2049.
34 Akhavan O. Graphene nanomesh by ZnO nanorod photocatalysts [J]. ACS Nano,2010,4(7):4174.
35 Jiang J Z, Zhu L H, Zou J, et al. Micro/nano-structured graphitic carbon nitride-Ag nanoparticle hybrids as surface-enhanced Raman scattering substrates with much improved long-term stability [J]. Carbon,2015,87(1):193.
36 Wen C, Yin A, Dai W, ChemInform abstract: Recent advances in silver-based heterogeneous catalysts for green chemistry processes [J]. Applied Catalysis B: Environmental,2014,160-161(1):730.
37 He B L, Dong B, Li H L. Preparation and electrochemical properties of Ag-modified TiO₂ nanotube anode material for lithium-ion battery [J]. Electrochemistry Communications,2007,9(3):425.