Visible-light CO 2 photocatalytic reduction performance of ball-flower-like Bi 2 WO 6 synthesized without organic precursor: Effect of post-calcination and water vapor
Visible-light CO 2 photocatalytic reduction performance of ball-flower-like Bi 2 WO 6 synthesized without organic precursor: Effect of post-calcination and water vapor
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DOI：
10.1016/j.apsusc.2014.07.153
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发表时间：
2014-10
影响因子：
6.7
通讯作者：
Zhuxing Sun;Zhenmei Yang;Hongfeng Liu;Haiqiang Wang;Zhongbiao Wu
中科院分区：
文献类型：
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作者：
Zhuxing Sun;Zhenmei Yang;Hongfeng Liu;Haiqiang Wang;Zhongbiao Wu
采用水热法在无有机前驱体的条件下合成了球形花状纳米片Bi 2 WO 6（PB-Bi 2 WO 6），并在连续流动反应体系中考察了其在可见光（420 nm <λ< 620 nm）照射下光催化还原CO2的性能。CO被检测到作为这个光催化过程的主要产品和H2O被发现抑制CO2到CO的转化，由于其竞争性吸收与CO2上的中等强度的碱性网站的Bi 2 WO 6。PB-Bi_2 WO_6在550 °C退火时，在水蒸气较少的条件下，表现出上级CO产率。XRD、SEM、UV-vis SRS、PL和CO2-TPD等表征结果表明，这可能是由于薄膜的结晶度提高，光生电子和空穴的复合速率显著降低，以及更稳定的碱性位有利于CO2的吸附。然而，与PB-Bi 2 WO 6相比，H2O的负面影响更加突出，因为退火样品的比表面积减少。在照射时间期间观察到产率降低，这是由于所产生的中间体的吸附，但幸运的是，发现用去离子水洗涤是更新催化剂的有效方式。
Nanoplates-composed ball-flower-like Bi2WO6(PB-Bi2WO6) was synthesized by a hydrothermal method without any organic precursor and its performance in photocatalytic reduction of CO2was investigated in a continuous-flow reaction system under visible light irradiation (420 nm <λ< 620 nm). CO was detected as the main product of this photocatalytic process and H2O was found to suppress the conversion of CO2to CO due to its competitive absorption with CO2on the medium strength basic sites of Bi2WO6. PB-Bi2WO6annealed at 550 °C showed superior CO yield in the condition with little water vapor. It might be attributed to the enhanced crystallinity, significantly decreased recombination rate of photo-generated electrons and holes and more stable basic sites for strengthened CO2adsorption, according to characterization results by XRD, SEM, UV–vis SRS, PL and CO2-TPD. However, comparing with PB-Bi2WO6, the negative effect of H2O was even more prominent on the annealed sample because of the reduced surface area. Yield decrease was observed during the irradiation time due to the adsorption of intermediates generated but fortunately washing with deionized water was found to be an effective way to renew the catalyst.