Wakizaka Masanori, Imaoka Takane, Yamamoto Kimihisa
Laboratory for Chemistry and Life Science Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, 226-8503, Japan.
Small. 2021 May;17(19):e2008127. doi: 10.1002/smll.202008127. Epub 2021 Mar 24.
Molybdenum oxycarbide clusters are novel nanomaterials that exhibit attractive catalytic activity; however, the methods for their production are currently very restrictive. This work represents a new strategy for the creation of near-subnanometer size molybdenum oxycarbide clusters on multilayer graphene. To adsorb Mo-based polyoxometalates of the type [PMo O ] as a precursor for Mo oxycarbide clusters, the novel tripodal-phenyl cation N,N,N-tri(4-phenylbutyl)-N-methylammonium ([TPBMA] ) is synthesized. [TPBMA] exhibits superior adsorption on multilayer graphene compared to commercially available cations such as tetrabutylammonium ([nBu N] ) and tetraphenylphosphonium ([PPh ] ). Using [TPBMA] as an anchor, highly dispersed precursor clusters (diameter: 1.0 ± 0.2 nm) supported on multilayer graphene are obtained, as confirmed by high-resolution scanning transmission electron microscopy. Remarkably, this new material achieves the catalytic reduction of CO to selectively produce CO (≈99.9%) via the reverse water-gas-shift reaction, by applying carbothermal hydrogen reduction to generate Mo oxycarbide clusters in situ.
碳氧化钼簇是具有吸引力的催化活性的新型纳米材料；然而，目前其制备方法非常有限。这项工作代表了一种在多层石墨烯上制备近亚纳米尺寸碳氧化钼簇的新策略。为了吸附作为碳氧化钼簇前体的[PMoO]型钼基多金属氧酸盐，合成了新型三脚架苯基阳离子N，N，N-三(4-苯基丁基)-N-甲基铵([TPBMA])。与市售阳离子如四丁基铵([nBuN])和四苯基鏻([PPh])相比，[TPBMA]在多层石墨烯上表现出优异的吸附性能。通过高分辨率扫描透射电子显微镜证实，以[TPBMA]为锚定剂，可获得负载在多层石墨烯上的高度分散的前体簇(直径：1.0±0.2nm)。值得注意的是，这种新材料通过碳热氢还原原位生成碳氧化钼簇，实现了通过逆水煤气变换反应将CO催化还原以选择性地生成CO(≈99.9%)。
