Noble metal-free Bi nanoparticles supported on TiO2 with plasmon-enhanced visible light photocatalytic air purification
Noble metal-free Bi nanoparticles supported on TiO2 with plasmon-enhanced visible light photocatalytic air purification
复制标题
DOI：
10.1039/c6en00341a
复制
发表时间：
2016-12
期刊：
影响因子：
--
通讯作者：
Zaiwang Zhao;Wendong Zhang;Xiaoshu Lv;Yanjuan Sun;F. Dong;Yuxin Zhang
中科院分区：
文献类型：
--
作者：
Zaiwang Zhao;Wendong Zhang;Xiaoshu Lv;Yanjuan Sun;F. Dong;Yuxin Zhang
半金属铋（Bi）是一种新兴的非贵金属基等离子体金属，其作为独特的等离子体光催化剂/助催化剂表现出优异的性能。在目前的工作中，Bi纳米颗粒均匀沉积在众所周知的二氧化钛颗粒（Degussa，P25）与金红石和金红石的混合相，通过一个简单的环保合成在室温下。在可见光（λ > 420 nm）照射下，Bi沉积的TiO 2纳米复合材料对空气中ppb级的NO具有显著的光催化降解性能。发现改善的光催化能力关键取决于催化剂结构：沉积在TiO 2颗粒表面的直径（dBi）为5-8 nm的Bi纳米颗粒充当可见光驱动的电子和空穴分离的活性位点。光致发光、光电流产生和Bode相光谱都很好地支持了增强的电荷分离。值得注意的是，优化的Bi-Ti-50样品（Bi与TiO 2的质量比为50%）的异常高的可见光光催化能力也上级普遍已知的非金属掺杂的TiO 2。通过SPR介导的Bi粒子的活化，随后通过连续的电子转移在Bi/金红石/Al 2 O3界面，增强了可见光的光致抗蚀剂的作用光谱的支持。由于Bi和金红石型TiO 2之间的高电位差，Bi粒子的等离子体激元激活产生的电子可以转移到金红石型TiO 2的导带，然后转移到相邻的金红石型TiO 2。此外，由于P25中高质量比的P25相，自由电子可以从Bi转移到P25的导带，然后转移到金红石型TiO 2，导致Bi纳米颗粒与P25中的TiO 2直接接触。基于活性粒子捕获理论，提出了Bi沉积TiO 2纳米复合材料的一种新的氧化机理。本文所阐述的促进等离子体激元分解的催化剂结构将有利于设计和开发更有效的可见光驱动的光催化剂用于环境修复，并可能为利用低成本的Bi纳米颗粒作为贵金属的替代物来提高太阳能的利用效率开辟新的途径。
Semimetal bismuth (Bi) is an emerging non-noble metal-based plasmonic metal, which has demonstrated exceptional behavior as a unique plasmonic photocatalyst/cocatalyst. In the present work, Bi nanoparticles were uniformly deposited on the well-known TiO2 particles (Degussa, P25) with mixed phases of anatase and rutile by a facile eco-friendly synthesis at room temperature. The Bi-deposited TiO2 nanocomposites demonstrated highly enhanced photocatalytic performance for removal of ppb-level NO in air under visible-light irradiation (λ > 420 nm). The improved photocatalytic capability was found to be crucially dependent on the catalyst architecture: Bi nanoparticles with a diameter (dBi) of 5–8 nm deposited on the surface of TiO2 particles acted as active sites for visible-light-driven electron and hole separation. The enhanced charge separation was well supported by photoluminescence, photocurrent generation and Bode-phase spectra. Significantly, the exceptionally high visible-light photocatalytic capability of the optimized Bi–Ti-50 sample (the mass ratio of Bi to TiO2 is 50%) was also superior to that of universally known non-metal-doped TiO2. The photocatalysis was enhanced through SPR-mediated activation of the Bi particles by visible light followed by consecutive electron transfer in Bi/rutile/anatase interfaces, as supported by the action spectra. The electrons produced from the plasmonic activation of Bi particles could transfer to the conduction band of rutile and then to adjacent anatase TiO2 because of the high potential difference between Bi and rutile TiO2. Also, the free electrons could transfer from Bi to the conduction band of anatase and then to rutile TiO2 owing to the high mass ratio of anatase phase in P25 resulting in the direct contact of the Bi nanoparticles and anatase TiO2. A new photocatalysis mechanism of Bi-deposited TiO2 nanocomposites was proposed on the basis of active species trapping. The catalyst architecture elucidated here for promoted plasmonic photocatalysis would be beneficial for the design and development of more effective visible-light-driven photocatalysts for environmental remediation and could open a new avenue for utilization of low-cost Bi nanoparticles as a substitute for noble metals to promote the utilization efficiency of solar energy.