Ou Lihui
Hunan Provincial Key Laboratory of Water Treatment Functional Materials, Hunan Province Engineering Research Center of Electroplating Wastewater Reuse Technology, College of Chemistry and Materials Engineering, Hunan University of Arts and Science, Changde 415000, China.
Langmuir. 2024 Jun 25;40(25):13060-13069. doi: 10.1021/acs.langmuir.4c00804. Epub 2024 Jun 13.
The role of halide anions and competing mechanisms between initial CO electroreduction pathways and hydrogen evolution reaction (HER) are systematically identified at halide anions modified Cu(111)/HO interfaces based on density functional theory calculations in this paper. The present results show that halide anions modified Cu(111)/HO interfaces can notably enhance electroreduction activity of CO into CO. Simultaneously, it is concluded that the specifically adsorbed halide anions modified Cu electrodes can inhibit HER by studying competing HER mechanisms, and thus the enhanced CO electroreduction activity can be ascribed to the suppressed HER. The origin of enhanced CO production activity and inhibited HER is further scrutinized. The present results show that the presence of halide anions can lead to stronger CO adsorption and the increased adsorption strength of CO can explain easier CO production based on the Sabatier principle. Interestingly, the calculated results show that the presence of halide anions does not exert an effect on H adsorption strength, which is regarded as a key descriptor of HER activity, implying that halide anions modified Cu electrodes may be not able to directly lead to the inhibited HER. However, the present results indicate that co-adsorbed CO can weaken adsorption strength between H and Cu electrodes and thus result in inhibited HER and decreased HER activity. The upshift of d-band centers of surface Cu atoms due to modification of halide anions may be a reason for stronger CO adsorption, whereas the downshift of the d-band center due to the presence of co-adsorbed CO can lead to a weakening effect on H adsorption strength. Our present insights into the role of halide anions can aid in designing an optimal electrolyte and developing electrocatalysts that are more selective toward CO electroreduction than HER.
基于密度泛函理论计算，本文系统地确定了卤化物阴离子在卤化物阴离子修饰的Cu(111)/HO界面上的作用，以及初始CO电还原途径与析氢反应（HER）之间的竞争机制。目前的结果表明，卤化物阴离子修饰的Cu(111)/HO界面可以显著提高CO电还原为CO的活性。同时，通过研究HER竞争机制得出，特异性吸附的卤化物阴离子修饰的Cu电极可以抑制HER，因此增强的CO电还原活性可归因于HER的抑制。进一步研究了增强CO生成活性和抑制HER的起源。目前的结果表明，卤化物阴离子的存在会导致更强的CO吸附，根据Sabatier原理，增加的CO吸附强度可以解释更容易生成CO。有趣的是，计算结果表明，卤化物阴离子的存在对H吸附强度没有影响，而H吸附强度被认为是HER活性的关键描述符，这意味着卤化物阴离子修饰的Cu电极可能无法直接导致HER的抑制。然而，目前的结果表明，共吸附的CO可以削弱H与Cu电极之间的吸附强度，从而导致HER受到抑制且HER活性降低。卤化物阴离子修饰导致表面Cu原子d带中心上移可能是CO吸附更强的一个原因，而共吸附CO的存在导致d带中心下移会对H吸附强度产生削弱作用。我们目前对卤化物阴离子作用的见解有助于设计最佳电解质，并开发对CO电还原比HER更具选择性的电催化剂。
