Ceria-confined mesoporous silica molecular sieve layer enables high-performance humidity-tolerant hydrogen sensors based on terbium-doped tin dioxide nanofibers

Authors:
  • WWWang Wang
    Wang Wang
  • WZWu Zhengkun
    Wu Zhengkun
  • YXYang XiYin
    Yang XiYin
  • YYYang Yifan
    Yang Yifan
  • GZGuoheng Zhang
    Guoheng Zhang
  • DGDuojie Gengzang
    Duojie Gengzang
  • PWPeiyu Wang
    Peiyu Wang
  • QCQiong Chen
    Qiong Chen
  • AXAn Xiujia
    An Xiujia
  • CZCairang Zhuoma
    Cairang Zhuoma
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Abstract
Humidity interference remains one of the most critical challenges hindering the practical applications of metal oxide semiconductor based hydrogen (H2) sensors. Although mesoporous silica molecular sieves have been widely used as protective diffusion layers to alleviate the adverse effect of humidity, maintaining long-term sensing performance under highly humid conditions is still challenging. Herein, we report a strategy of confining ultrasmall CeO2 particles within the channels of mesoporous silica molecular sieve (CeO2-SBA-15) materials to enhance the humidity tolerance of electrospinning terbium-doped tin dioxide nanofiber-based (Tb-SnO2)-based H2 sensors. In this design, the synergistic effect of gas enrichment within the mesoporous SBA-15 diffusion layer and the superior catalytic activity of channel-confined CeO2 substantially enhances the sensor's H2 response. More importantly, the confined CeO2 introduces abundant reversible redox sites through the Ce3⁺/Ce4⁺ pairs, thereby promoting oxygen activation, facilitating surface reaction kinetics, and mitigating humidity-induced performance degradation. As a result, the optimized Tb-SnO2/5% CeO2-SBA-15 sensor delivers a high response of 69.23 toward 10 ppm H2 at 280℃, an ultralow detection limit of 20 ppb, excellent linearity over a wide concentration range, rapid response/recovery, and outstanding selectivity. Notably, the sensor retains over 85% of its initial response even at 85% RH, much higher than that for the Tb-SnO2/SBA-15 one (51%). This work provides a versatile strategy for integrating catalytically active species into functional porous molecular sieves, offering new insights into the development of high-performance and humidity-tolerant gas sensors for H2 and other target gases.

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