Polyoxometalates (POMs), emerging as a new class of porous molecular materials, play a promising role in homo- and heterogeneous catalysis. Among them, noble-metal-decorated POMs have a profound impact as catalytic materials. Thus, it is imperative to design and structurally explore new catalysts including noble metals. Herein, two new clusters, H₃[(Cp*Rh)₄PMo₈O₃₂]·14H₂O (1) and H₅[Na₂(Cp*Ir)₄PMo₈O₃₄]·13H₂O (2) (Cp* = pentamethylcyclopentadienyl), based on a heterooctamolybdate anionic core were successfully obtained via a one-pot reaction using [Cp*MCl₂]₂ [M = Rh (1) and Ir (2)] and Na₂MoO₄ in acidic conditions. Compounds 1 and 2 were well characterized in the solid state by single-crystal X-ray diffraction, IR, and thermogravimetric analysis and in solution by UV–vis, electrospray ionization mass spectrometry, and electrochemistry. Compounds 1 and 2 represent an important class of structurally isolated organometallic POM-based clusters that were successfully nanostructured onto Ni foam and electrochemically reduced after 48 h of electrolysis to M/MoO₂, where M = Rh (3) and Ir (4), nanocomposite hybrid materials on a Ni foam surface in a 0.1 M KOH solution. The modified electrocatalysts (3 and 4) show efficient hydrogen evolution reaction activities almost comparable to those of high-grade Pt/C at 0.1 M KOH. The nanostructured POMs [1- and 2@NF (Ni foam)] and their corresponding reduced products (3 and 4) were observed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and X-ray photoelectron spectroscopy and further proven by transmission electron microscopy (TEM) and high-resolution TEM.

中文翻译：

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基于杂八钼酸盐的簇H ₃ [（（Cp * Rh）₄ PMo ₈ O ₃₂ ]和H ₅ [Na ₂（Cp * Ir）₄ PMo ₈ O ₃₄ ]和具有高效电催化氢释放反应活性的杂化纳米材料

多金属氧酸盐（POM），作为一种新型的多孔分子材料，在均相和非均相催化中起着有希望的作用。其中，装饰有贵金属的POM作为催化材料具有深远的影响。因此，必须设计和结构上探索包括贵金属在内的新型催化剂。在这里，两个新的簇H ₃ [（（Cp * Rh）₄ PMo ₈ O ₃₂ ]·14H ₂ O（1）和H ₅ [Na ₂（Cp * Ir）₄ PMo ₈ O ₃₄ ]·13H ₂ O（2）（CP * =五甲基环戊二烯）的基础上，heterooctamolybdate阴离子芯分别通过一釜反应中使用的[Cp *的MC1成功地获得₂ ] ₂ [M =铑（1）和Ir（2）]和Na ₂的MoO ₄在酸性条件。通过单晶X射线衍射，IR和热重分析，以及在溶液中通过UV-vis，电喷雾电离质谱和电化学对化合物1和2进行了很好的表征。化合物1和2代表了一类重要的结构分离的有机金属POM基团簇，它成功地纳米结构到镍泡沫上，电解48h后电化学还原成M / MoO ₂，其中M = Rh（3）和Ir（4），纳米复合杂化材料。在0.1 M KOH溶液中的泡沫镍表面。改性的电催化剂（3和4）显示出与在0.1 M KOH下高等级Pt / C几乎可比的有效氢释放反应活性。纳米结构的POM [ 1和2 @NF（镍泡沫）]及其相应的还原产物（3和4）通过扫描电子显微镜，能量色散X射线光谱，粉末X射线衍射和X射线光电子光谱进行观察，并进一步通过透射电子显微镜（TEM）和高分辨率TEM进行了验证。