g-C3N4/(Cu/TiO2) nanocomposite for enhanced photoreduction of CO2 to CH3OH and HCOOH under UV/visible light
g-C3N4/(Cu/TiO2) nanocomposite for enhanced photoreduction of CO2 to CH3OH and HCOOH under UV/visible light
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DOI：
10.1016/j.jcou.2017.02.004
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发表时间：
2017-03-01
影响因子：
7.7
通讯作者：
Amin, Nor Aishah Saidina
中科院分区：
文献类型：
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作者：
Adekoya, David Oluwatobi;Tahir, Muhammad;Amin, Nor Aishah Saidina
研究了cu修饰的石墨氮化碳（g-C3N4）和二氧化钛（TiO2）纳米复合材料在紫外和可见光下对H2O光催化还原CO2的增强作用。采用XRD、FE-SEM、TEM、FT-IR、N-2吸附-解吸、XPS、UV-vis DRS和PL光谱对热解和浸渍法制备的光催化剂进行了表征。负载在TiO2和g-C3N4上的cu通过促进载流子电荷分离，提高了CO2对CH3OH和HCOOH的还原效率。复合材料中cu的含量以及g-C3N4和TiO2的wt.%的比例也影响了光活性和产物选择性。g-C3N4的低带隙、电子结构和可见光吸收能力有利于光生电子向复合材料中的Cu/TiO2转移。此外，金属在复合材料中的位置影响了电子分布，从而增强了光活性。产物在可见光下的最大产率分别为2574和5069 μ mol/g。CH3OH和HCOOH的cat。在可见光下CH3OH的产率比紫外光下高4倍。复合材料中g-C3N4与Cu/TiO2的比例（30:70）和可见光的使用提高了光催化体系的效率。在可见光照射下连续生产CH3OH时，光催化剂的稳定性优于紫外光循环生产。为了了解g-C3N4/TiO2（30:7 0）光催化剂上电子和空穴的运动以及紫外和可见光对CO2还原的作用，提出了可能的反应机理。(C) 2017 Elsevier Ltd.版权所有。
Cu-modified graphitic carbon nitride (g-C3N4) and titanium dioxide (TiO2) nanocomposites for enhanced photocatalytic CO2 reduction with H2O under UV and visible light irradiations have been investigated. The photocatalysts, prepared by pyrolysis and impregnation were characterized by XRD, FE-SEM, TEM, FT-IR, N-2 adsorption-desorption, XPS, UV-vis DRS and PL spectroscopy. The Cu-metal loaded over TiO2 and g-C3N4 enhanced CO2 reduction efficiency to CH3OH and HCOOH by fostering carrier charge separation. The Cu-metal in the composite as well as the wt.% ratio of g-C3N4 and TiO2 also influenced the photoactivity and products selectivity. The low band gap, electronic structure and visible light absorption capacity of g-C3N4 facilitated the transfer of photo-generated electrons to Cu/TiO2 in the composite. Moreover, the position of the metal in the composite affected the electrons distribution and hence enhanced the photoactivity. The maximum yield of the products detected under visible light were 2574 and 5069 mu mol/g. cat of CH3OH and HCOOH, respectively. The yield of CH3OH under visible light was four fold higher compared to UV-light irradiation. The ratio (30:70) of g-C3N4 and Cu/TiO2 in the composite and the use of visible light improved the efficiency of the photocatalytic system. The stability of the photocatalyst prevailed in continuous CH3OH production under visible light irradiation compared to UVlight in cyclic runs. Possible reaction mechanisms were proposed to understand the movement of electrons and holes and the function of both UV and visible light for CO2 reduction over the g-C3N4/TiO2 (30: 70) photocatalyst. (C) 2017 Elsevier Ltd. All rights reserved.