具有缺陷结构的Au负载ZnSn-LDH通过氧定向活化实现甲烷选择性光催化氧化偶联

Selective photocatalytic oxidative coupling of methane via directional activation of oxygen over Au-loaded ZnSn-LDH with defect structure

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DOI 10.1016/j.apcatb.2024.124670
刊名
年,卷(期) 2024, 361()
作者
作者单位 宁夏大学

摘要
甲烷选择性光催化氧化偶联反应在将低成本原料转化为C2产物方面具有巨大潜力。然而,如何通过催化剂设计提升光催化OCM活性,并深入理解OCM过程中的反应物活化机制仍面临挑战。本研究合成了具有氧空位的Au-ZnSn-LDH,实现了以O2为氧化剂的高效甲烷选择性氧化。优化后的复合催化剂表现出2666 μmol·g?1·h?1的乙烷产率和76.8%的选择性。研究结果表明,ZnSn-LDH表面的氧(可能吸附于氧空位)在金助催化剂的辅助下,为O2活化为O2?提供了位点。O2?可由O2转化生成,在光激发下能选择性地促进甲烷C-H键活化,展现理想的反应活性。金助催化剂在促进甲基转移、加速C-C偶联以生成主要产物乙烷,并避免不利的过度氧化反应方面起着关键作用。
Abstract
The selective photocatalytic oxidative coupling of methane (OCM) holds great potential in converting low-cost feedstock into C2 products. However, the challenge lies in improving the photocatalytic OCM activity through catalyst design and gaining a deeper understanding of reactant activation in the OCM process. Here, we synthesized Au-ZnSn-LDH with oxygen vacancies to achieve efficient selective oxidation of methane using O2. The optimal hybrid exhibits a C2H6 yield of 2666 μmol g? 1 h? 1 and 76.8 % selectivity. Our findings showed that the oxygen within the surface of ZnSn-LDH (possibly from adsorption at Ov vacancy sites) provides sites for the evolution of O2 to O2 with assistance from Au cocatalyst. More O2 could be generated from O2 provides a desired reactivity to selectively promote selective C? H activation of CH4 under photoexcitation. The Au cocatalyst plays crucial roles in facilitating the methyl transfer and promoting C? C coupling to produce C2H6 as the main product while avoiding undesirable overoxidation.
关键词
Au负载ZnSn层状双氢氧化物;光催化;C-H键活化;甲烷氧化偶联;乙烷
KeyWord
Au-ZnSn-LDH;Photocatalysis;C-H activation;Oxidative methane coupling;C2H6
基金项目
页码 1-8
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张金宇, 冯晓燕, 李莉 * , 王萍, 梁军 *. 具有缺陷结构的Au负载ZnSn-LDH通过氧定向活化实现甲烷选择性光催化氧化偶联 [J]. Applied Catalysis B: Environment and Energy. 2024; 361; (). 1 - 8.

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