NiFe_2O_4/g-C_3N_4的制备及可见光催化降解甲基橙

采用浸渍法制备不同负载量NiFe_2O_4的负载型光催化剂NiFe_2O_4/g-C_3N_4,利用XRD、FT-IR、N_2-adsorption、ICP-OES、TEM及XPS等手段表征NiFe_2O_4/g-C_3N_4样品,并考察其对甲基橙的可见光催化降解性能。结果表明,与NiFe_2O_4和g-C3N4样品相比,负载型NiFe_2O_4/g-C_3N_4样品对甲基橙具有更好的光催化降解活性,且催化活性随着NiFe_2O_4负载量增大(0.5~5.0wt%)而呈现先增大再减小的趋势。NiFe_2O_4负载量2.0wt%的样品2-Ni Fe/CN在可见光照射下对浓度5 mg·L~(-1)的甲基橙表现出最好的降解活性和稳定性。这是因为能带宽度小(1.5 e V)的NiFe_2O_4与能带宽度大(2.7 e V)的g-C_3N_4形成的异质结催化剂NiFe_2O_4/g-C_3N_4,有效地促进光生载流子在二者界面快速传递和光生电子-空穴对的有效分离。

Synthesis of NiFe2O4/g-C3N4 for the Photocatalytic Degradation of Methyl Orange under Visible-light Irradiation

The supported photocatalysts NiFe 2 O4/g-C3 N4 with different NiFe2 O4 content were synthesized by impregnation method and performed on the photocatalytic degradation of methylene orange ( MO ) under visible-light region.Several techniques, including XRD, FT-IR, N2-adsorption, ICP-IOS SEM, TEM and XPS, were employed to obtain the physical and chemical properties of NiFe 2 O4/g-C3 N4 samples.The results indicate that the supported catalyst NiFe 2 O4/g-C3 N4 exhibited higher photocatalytic activity of MO compared to NiFe 2 O4 and g-C3 N4 .The catalytic activity of NiFe 2 O4/g-C3 N4 sample increased and then decreased with the increasing NiFe 2 O4 doping amount ranged from 0.5wt% to 5. 0wt%, of which the 2-NiFe/CN sample with 2.0wt% NiFe2 O4 loading exhibited the best degradation activity and stability for the photocatalytic degradation of methyl orange (5 mg· L-1 ) under visible light irradiation.It's ascribed to the heterojunction structure of NiFe 2 O4/g-C3 N4 sample formed between narrow energy band (1.5 eV) of NiFe2 O4 and wide energy band (2.7 eV) of g-C3 N4 , which facilities the speed transmission of photoexcited carriers at the interface of NiFe 2 O4 and g-C3 N4 , and enhances the effective separation of electron-hole pairs.