Nickel selenide as an efficient electrocatalyst for selective reduction of carbon dioxide to carbon-rich products
Nickel selenide as an efficient electrocatalyst for selective reduction of carbon dioxide to carbon-rich products
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DOI：
10.1039/d2cy00583b
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发表时间：
2022-06-03
影响因子：
5
通讯作者：
Nath, Manashi
中科院分区：
文献类型：
--
作者：
Saxena, Apurv;Liyanage, Wipula P. R.;Nath, Manashi
确定用于二氧化碳电还原为高价值产品的新催化剂组合物在过去几年中一直是吸引人的中心。在这篇文章中，硒化镍（NiSe 2）已被确定为在中性pH下用于CO2电还原的高效电催化剂。有趣的是，NiSe 2对特定还原产物显示出高选择性，仅在较低的外加电位下形成富碳的C2产物，如乙醇和乙酸，法拉第效率为98.45%，而C1产物甲酸和一氧化碳在较高的外加电位下优先生成。更重要的是，C2产物如乙酸和乙醇在非常低的应用电位下获得，这进一步证实了该催化剂在以最小的能量消耗利用CO2方面的新奇。通过密度泛函理论计算研究了NiSe 2催化剂表面，结果表明，CO中间体在NiSe 2表面上的吸附能对于通过形成C-C键的广泛还原是最佳的，但对于表面钝化来说不够强，从而导致对C2产物的高选择性。催化剂的这种高效率可以是硒化物阴离子的增加的共价性沿着Ni中心的高d-电子密度的结果。水热合成的NiSe 2样品还通过在碱性介质中电催化水裂解显示出高的析氧活性，有效地使其成为双功能催化剂，其可以降低大气污染物CO2的浓度，同时用O-2富集空气。
Identifying new catalyst composition for carbon dioxide electroreduction to high-value products has been the center of attraction over the last several years. In this article, nickel selenide (NiSe2) has been identified as a high-efficiency electrocatalyst for CO2 electroreduction at neutral pH. Interestingly, NiSe2 shows high selectivity towards specific reduction products, forming carbon-rich C2 products like ethanol and acetic acid exclusively at lower applied potential with 98.45% faradaic efficiency, while C1 products formic acid and carbon monoxide formed preferentially at higher applied potential. More importantly, the C2 products such as acetic acid and ethanol are obtained at very low applied potential, which further corroborates the novelty of this catalyst in CO2 utilization with minimal energy expense. The NiSe2 catalyst surface has been studied through density functional theory calculations which show that the adsorption energy of the CO intermediate on the NiSe2 surface is optimal for extensive reduction through formation of C-C bonds but not strong enough for surface passivation, thus leading to high selectivity for C2 products. Such high efficiency of the catalyst can be a result of increased covalency of the selenide anion along with a high d-electron density of the Ni center. The hydrothermally synthesized NiSe2 sample also shows high activity for oxygen evolution through electrocatalytic water splitting in alkaline medium, effectively making it a bifunctional catalyst which can lower the concentration of the atmospheric pollutant CO2 while at the same time enriching the air with O-2.