Sulfur spillover driven by charge transfer between AuPd alloys and SnO2 allows high selectivity for dimethyl disulfide gas sensing
Sulfur spillover driven by charge transfer between AuPd alloys and SnO2 allows high selectivity for dimethyl disulfide gas sensing
复制标题
AuPd 合金和 SnO2 之间的电荷转移驱动的硫溢出可实现二甲基二硫醚气体传感的高选择性
DOI：
10.1016/j.cej.2021.129881
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发表时间：
2021-04-23
影响因子：
15.1
通讯作者：
Duan, Guotao
中科院分区：
文献类型：
--
作者：
Liu, Bo;Li, Ke;Duan, Guotao
单金属催化剂改性是提高半导体金属氧化物气敏元件性能的常用方法，但其催化活性类型单一，难以保证传感器性能的高水平调节。本文通过密度泛函理论（DFT）计算和原位测试技术相结合的方法，研究了在传感器表面引入镍基合金催化剂对传感器表面电子结构和反应动力学过程的调控。当用AuPd合金修饰SnO 2表面时，它表现出明显的区分性传感行为，在135 ℃下对10 ppm二甲基二硫（DMDS）气体具有高的响应信号（R-air/R-gas = 36.6）和超高的选择性，这与纯SnO 2、单金属Au或Pd掺杂的SnO 2有很大不同。DFT计算证实了AuPd合金向SnO 2的电荷转移以及DMDS表面吸附强度的增强，这可能是DMDS具有高气体响应的主要原因。原位漫散射傅里叶变换红外光谱和准原位XPS测试表明，DMDS分子的表面反应位点主要位于AuPd合金表面，合金表面对SnO 2产生的“硫溢出”在DMDS传感过程中起着至关重要的作用，动力学反应途径计算进一步验证了这一点。该工作将丰富催化电子学在传感器领域的基础研究。
Monometallic-catalyst modification is a popular means for boosting sensing performances of gas sensors based on semiconductor metal oxides, but it is restricted to the single-type of catalytic activity, hardly insuring high-level regulation of sensor performances. Herein, through combining density functional theory (DFT) calculations and in-situ testing technologies, we presented the modulation of both electronic structure and reaction kinetic process of the sensing surfaces by introducing bimetal alloy catalysts. When used AuPd alloys to modify SnO2 surfaces, it appeared obviously discriminative sensing behaviors, possessing high response signal (R-air/R-gas = 36.6) and ultra-high selectivity to 10 ppm dimethyl disulfide (DMDS) gas at 135 degrees C, which is considerably different from pure SnO2, monometallic Au or Pd doped SnO2. DFT calculations confirmed the occurrence of the charge transfer that was from AuPd alloys to SnO2 and the reinforce of surface adsorption strength for DMDS, which may be a major reason for a high gas response to DMDS. In-situ diffuse scattering Fourier transform infrared spectra and quasi in-situ XPS test demonstrated that the surface reaction site for DMDS molecules was mainly located on surfaces of AuPd alloys, and the "sulfur spillover" that generated from alloys surfaces to SnO2 played a crucial role during DMDS-sensing process, which was further validated by kinetic reaction-pathway calculations. This work will enrich basic research of catalytic electronics in sensor field.