Modulating the mechanism of electrocatalytic CO2 reduction by cobalt phthalocyanine through polymer coordination and encapsulation
Modulating the mechanism of electrocatalytic CO2 reduction by cobalt phthalocyanine through polymer coordination and encapsulation
复制标题
DOI：
10.1038/s41467-019-09626-8
复制
发表时间：
2019-04-11
影响因子：
16.6
通讯作者：
McCrory, Charles C. L.
中科院分区：
文献类型：
--
作者：
Liu, Yingshuo;McCrory, Charles C. L.
选择性和高效的电化学还原CO2为单一产品是太阳能燃料开发的关键。将分子催化剂如酞菁钴封装在配位聚合物如聚-4-乙烯基吡啶内导致显著增加的CO2还原活性和选择性。在这项研究中，我们使用动力学同位素效应和质子库存研究的组合来解释聚合物封装后所观察到的活性和选择性的增加。我们提供的证据表明，从聚-4-乙烯基吡啶的吡啶基部分的钴酞菁配合物的轴向协调改变的CO2还原机制占催化剂-聚合物复合材料的活性增加的速率决定步骤。此外，我们表明，质子传递到聚合物内的钴中心控制的质子中继机制，抑制竞争性氢的演变。这些机制的研究结果提供了选择性CO2还原电催化剂的设计策略，并作为理解相关的非均相系统的催化机理的模型。
The selective and efficient electrochemical reduction of CO2 to single products is crucial for solar fuels development. Encapsulating molecular catalysts such as cobalt phthalocyanine within coordination polymers such as poly-4-vinylpyridine leads to dramatically increased activity and selectivity for CO2 reduction. In this study, we use a combination of kinetic isotope effect and proton inventory studies to explain the observed increase in activity and selectivity upon polymer encapsulation. We provide evidence that axial-coordination from the pyridyl moieties in poly-4-vinylpyridine to the cobalt phthalocyanine complex changes the rate-determining step in the CO2 reduction mechanism accounting for the increased activity in the catalyst-polymer composite. Moreover, we show that proton delivery to cobalt centers within the polymer is controlled by a proton relay mechanism that inhibits competitive hydrogen evolution. These mechanistic findings provide design strategies for selective CO2 reduction electrocatalysts and serve as a model for understanding the catalytic mechanism of related heterogeneous systems.