纳米二氧化钛负载银离子Ag-TiO_(2)的可见光催化还原CO_(2)性能研究

Visible Photocatalytic Reduction of CO_(2) by TiO_(2) Nanoparticles Loaded With Silver Ions

采用Ti O_(2)P25准纳米立方体,平均尺寸约为25 nm。作为CO_(2)光还原的催化剂,结果表明银纳米颗粒的粒径及其在Ti O_(2)P25纳米立方体表面的分布受载银量的显著影响,从而导致CO_(2)光催化还原生成CO/CH4的活性和选择性存在明显差异。同时探究了反应物流速对催化反应的影响,不同催化剂在均在200 m L·min^(-1)的反应物流速下表现出最佳的反应活性,切向的物质交换比较剧烈,同时在催化剂表面的边界层比较薄,不会阻碍催化剂与反应物之间的吸附与脱附过程。在反应物流速200 m L·min^(-1)情况下1.0%Ag-Ti O_(2)P25表现出最高的总活性,CO/CH4生成速率为1670.36/181.08μL·(h·g)^(-1),CO生成活性提高了39.38%,CH_(4)生成活性是原始Ti O_(2)P25的3.75倍。本研究结果为银负载对Ti O_(2)P25二氧化钛暴露面CO_(2)光还原反应活性和选择性的影响提供了重要依据,并展示了一种通过改变Ti O_(2)P25的形貌和表面结构来调节CO_(2)光还原性能的策略。

TiO_(2) P25 quasi-nanocubes with an average size of about 25 nm were used as catalysts for CO_(2) photoreduction,and the results showed that the particle size of silver nanoparticles and their distribution on the surface of TiO_(2) P25 nanocubes were significantly influenced by the amount of silver loaded,which led to significant differences in the activity and selectivity of CO_(2) photocatalytic reduction to CO/CH4.The effect of the reactant fow rate on the catalytic reaction was also investigated.The different catalysts showed the best reactivity at the reactant flow rate of 200 mL-min-1,where the tangential material exchange was relatively intense,while the boundary layer on the catalyst surface was relatively thin and did not hinder the adsorption and desorption processes between the catalyst and the reactants.The 1.0%Ag-TiO_(2) P25 showed the highest total activity at a reactant flow rate of 200 mL·min^(-1) with a CO/CH4 generation rate of 1670.36/181.08μL·(h:g)^(-1),which increased the CO generation activity by 39.38%and the CH4 generation activity was 3.75 times higher than that of the pristine TiO_(2) P25.The results of this study provide an important basis for the effect of silver loading on the activity and selectivity of the CO_(2) photoreduction reaction on the exposed surface of TiO_(2) P25 titanium dioxide and demonstrate a strategy to modulate the CO_(2) photoreduction performance by changing the morphology and surface structure of TiO_(2) P25.