In-situ regeneration of Au nanocatalysts by atmospheric-pressure air plasma: Significant contribution of water vapor
In-situ regeneration of Au nanocatalysts by atmospheric-pressure air plasma: Significant contribution of water vapor
复制标题
DOI：
10.1016/j.apcatb.2015.05.020
复制
发表时间：
2015-12
影响因子：
22.1
通讯作者：
Bin Zhu;Xiao‐Song Li;Jing‐Lin Liu;Jin-Bao Liu;Xiaobing Zhu;Aimin Zhu
中科院分区：
文献类型：
--
作者：
Bin Zhu;Xiao‐Song Li;Jing‐Lin Liu;Jin-Bao Liu;Xiaobing Zhu;Aimin Zhu
CO氧化过程中失活的Au纳米催化剂的原位再生通过纯氧等离子体有效地进行，但是在我们先前的工作中被干燥空气等离子体毒害（Appl.Catal.B2012，119 -120，49-55）。在前人研究的基础上，探索了一种简单有效的湿空气大气压冷等离子体原位再生Au纳米催化剂的技术。与通过干等离子体的无效再生相比，由于水蒸气的显著贡献，使用合成空气（20%O2平衡N2）作为放电气体的湿等离子体令人惊讶地在Au催化剂上表现出有效的再生性能。在等离子体再生5 min后，Au催化剂在2.77 vol. %（质量分数）的湿等离子体中的再生率显著提高，达到98水，而在干血浆下下降至负29%。为揭示水蒸气对再生效果的贡献机理，对再生催化剂进行了表征，并对等离子体再生过程中的放电特性和气体产物进行了分析。水蒸气的显著贡献体现在它加速碳酸盐物种的分解，同时抑制氮氧化物有毒物种的形成。在此基础上，采用普通空气代替合成空气进行湿等离子体再生，对经过长期反应和10次失活-再生循环后的Au催化剂进行了评价，验证了原位等离子体再生纳米Au催化剂的可行性和可靠性。
In-situ regeneration of deactivated Au nanocatalysts during CO oxidation, was conducted effectively by pure oxygen plasma, but poisoned by dry air plasma in our previous work (Appl.Catal.B2012,119–120, 49–55). With extension of previous study, a simple and effective technique of atmospheric-pressure cold plasma of humid air is explored for in-situ regeneration of Au nanocatalysts. In comparison with ineffective regeneration by dry plasma, humid plasma using synthetic air (20% O2balance N2) as discharge gas surprisingly exhibited effective regeneration performance over Au catalyst due to significant contribution of water vapor. After plasma regeneration for 5 min, the regeneration degree of Au catalysts significantly increased up to 98% under humid plasma in presence of 2.77 vol.% water, while decreased down to negative 29% under dry plasma. To disclose the mechanism of water vapor contribution to greatly improved regeneration degree, the characterizations of regenerated catalysts, and the analyses of electric discharge characteristics and gaseous products during the plasma regeneration were conducted. The significant contribution of water vapor embodies in that it speeds up the decomposition of carbonate species and simultaneously inhibits the formation of poisoning species of nitrogen oxides. Furthermore, normal air instead of synthetic air in humid plasma regeneration was implemented on the evaluations of the deactivated Au catalysts after a long-term reaction and during ten deactivation-regeneration cycles, which ensured the feasibility and reliability of in-situ plasma regeneration of Au nanocatalysts as a simple, effective and promising technique.