Engineering electrophilic atomic Ir sites on CeO2 colloidal spheres for selectivity control in hydrogenation of α,β-unsaturated carbonyl compounds
Engineering electrophilic atomic Ir sites on CeO2 colloidal spheres for selectivity control in hydrogenation of α,β-unsaturated carbonyl compounds
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CeO2 胶体球上的工程亲电原子 Ir 位点用于 α,β-不饱和羰基化合物氢化的选择性控制
DOI：
10.1007/s12274-022-4405-4
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发表时间：
2022-05-31
期刊：
影响因子：
9.9
通讯作者：
Chen, Zheng
中科院分区：
文献类型：
--
作者：
Mateen, Muhammad;Akhtar, Muhammad Nadeem;Chen, Zheng
α，β-不饱和羰基化合物中羰基键的选择性加氢是一个相当具有挑战性的问题，因为烯键的加氢无论从热力学还是动力学方面都是可行的。在这里，我们展示了一个简单的乳液为基础的分子-纳米粒子自组装策略的原子工程的Ir物种的三维CeO 2球（Ir-1@CeO2）。当应用于α，β-不饱和醛的加氢反应时，Ir-1@CeO2催化剂对不饱和醇的选择性接近100%，而Ir纳米颗粒的形成使不饱和醇的选择性显著降低。光谱研究表明，强的金属-载体相互作用引发了Ir向CeO 2的电荷转移，导致Ce 4+部分还原为Ce 3+，同时沿着形成新的Ir δ +-O2--Ce 3+（O-V）界面。因此，在Ir δ +-O2--Ce 3+（O-V）界面处的亲电原子Ir物种将优先吸附并促进极性C=O键的氢化以实现优异的选择性。
Selective hydrogenation of the carbonyl bond in a,beta-unsaturated carbonyl compounds is rather challenging owing to the more feasible hydrogenation of ethylenic bond from both thermodynamic and kinetic aspects. Here, we demonstrate a facile emulsion-based molecule-nanoparticle self-assembly strategy for the atomic engineering of Ir species on three-dimensional CeO2 spheres (Ir-1@CeO2). When applied to the hydrogenation of a,beta-unsaturated aldehydes, Ir-1@CeO2 catalyst remarkably exhibited similar to 100% selectivity towards unsaturated alcohols, whereas the formation of Ir nanoparticles on CeO2 drastically decreased the selectivity for unsaturated alcohols. Spectroscopic studies revealed that strong metal-support interactions triggered the charge transfer from Ir to CeO2, leading to the partial reduction of Ce4+ to Ce3+ along with the formation new Ir delta+-O2--Ce3+(O-V) interfaces. The electrophilic atomic Ir species at the Ir delta+-O2--Ce3+ (O-V) interfaces would therefore preferentially adsorb and facilitate hydrogenation of polar C=O bond to achieve exceptional selectivity.