银负载三氧化钨高选择性光催化甲烷转化

Highly Selective Photocatalytic Methane Oxidation with Silver-loaded Tungsten Trioxide

利用太阳能驱动的甲烷转化,实现高选择性制备化学增值品,对社会可持续发展具有重要意义。在本工作中,制备了负载银的暴露(002)、(200)和(020)面的立方三氧化钨(cWO_(3))。光照下,cWO_(3)中丰富的晶格氧能够活化甲烷,形成*OCH_3中间体,实现高选择性制备HCHO。实验发现消耗的晶格氧可以被氧气补充,以实现甲烷的可持续转化。cWO_(3)表面的银作为空穴接受体,抑制晶格氧参与HCHO转化过程,促进CH_3OH生成。通过控制银在立方三氧化钨的负载量(Ag_x/cWO_(3))实现高选择性的甲烷转化,Ag_(0.13)/cWO_(3)对甲醛的选择性为99.1%,Ag_(1.21)/cWO_(3)对甲醇的选择性为91.4%。这项工作为温和条件下的光催化甲烷转化开辟了一条途径。

It is of great significance for the sustainable development of society to realize the highly selective preparation of chemical value-added products by using the methane conversion driven by solar energy.In this work,exposed(002),(200)and(020)cubic tungsten trioxide(cWO_(3))loaded with silver was prepared.Under light,abundant lattice oxygen in cWO_(3)can activate methane and form intermediate methoxyl active group*OCH3 intermediates to achieve highly selective preparation of HCHO.The experiment found that the consumed lattice oxygen could be supplemented with oxygen to achieve a sustainable conversion of methane.Silver on the surface of cWO_(3)acts as a hole acceptor,which inhibits lattice oxygen from participating in HCHO transformation process and promotes CH3OH formation.The highly selective methane conversion was achieved by controlling the loading of silver in cubic tungsten trioxide(Agx/cWO_(3)).Ag0.13/cWO_(3)was 99.1%for formaldehyde and Ag1.21/cWO_(3)was 91.4%for methanol.This work opens up a pathway for photocatalytic conversion of methane under mild conditions.