Bi_2O_3/RGO的制备及其光催化还原CO_2性能的研究

Preparation and photo-catalytic performance of Bi_2O_3/RGO composite catalysts for the reduction of carbon dioxide

利用氨沉淀法制备Bi_2O_3粉体,采用改进的Hummers法制备GO,将Bi_2O_3加入一定量的GO分散液中,采用紫外还原法制备Bi_2O_3/RGO复合光催化剂,通过XRD、SEM、EDS、BET等技术手段对催化剂进行表征,并考察其在紫外光下催化还原CO_2的性能。结果表明,GO在紫外照射过程中被有效地还原为RGO,与晶粒尺寸约为49nm的单斜晶系Bi_2O_3颗粒在紫外照射下共同搅拌,形成Bi_2O_3/RGO复合物,其Bi_2O_3的主要衍射峰发生轻微宽化,石墨烯碎片、絮状物质附着在Bi_2O_3表面;随着GO含量的增加,Bi_2O_3表面附着的石墨烯碎片、絮状物质增加,复合催化剂的比表面积增大;在紫外光照射下,Bi_2O_3/RGO复合催化剂的光催化效果明显高于Bi_2O_3,GO含量为2.0%(质量分数)的Bi_2O_3/RGO复合催化剂,在光照时间为8h时,生成CH_4的产量为1.012μmol/g,比Bi_2O_3提高了96.5%。

Ammonia precipitation and improved Hummer method were used to prepare Bi2 O3 and GO respective-ly.Bi2 O3 were dissolve into appropriate concentrated GO solution followed by preparation of Bi2 O3/RGO com-posite catalyst using UV reduction method.XRD,SEM,EDS and BET were employed to characterize the pho-tocatalysts.Meanwhile,the photocatalytic capacity was evaluated by performing photocatalytic reduction of CO2 under ultraviolet light.The results indicated that GO was efficiently reduced to RGO under UV radiation. Monoclinic Bi2 O3 with 49 nm grain size and GO solution were mixed under UV radiation to form Bi2 O3/RGO composite,which exhibited slightly broadening of main diffraction peaks compared to pure Bi2 O3 .With the in-creasing concentration of GO,the amount of the graphene fragments and flocculent material that attached to the surface of Bi2 O3 grows and the specific surface areas of the composite catalysts increase.Under UV irradiation, Bi2 O3/RGO composite catalysts have significantly stronger photocatalytic effect than Bi2 O3 .In the condition of 8 h-UV radiation,the composite catalyst with 2.0wt% GO produces 1.012μmol/g CH4 ,whose yield is 96.5%higher than pure Bi2 O3 .