Copper has been extensively studied for electrocatalytic CO₂ reduction reaction (CO₂RR) due to its unique capability to produce hydrocarbons at high overpotentials. Although CO₂RR on crystallographic Cu surfaces such as Cu(211) and Cu(111) has been investigated by many, the detailed mechanistic understanding of CO₂RR on small Cu nanoparticles (NP) is still lacking. In this work, we use Cu₇₉ as a representative NP and compare it with Cu(211) and Cu(111) for reduction of CO₂ to CH₄ by first-principles calculations. The computed free energy profiles show that the Cu₇₉ NP exhibits less negative onset potential for the formation of CO than both Cu(211) and Cu(111) but more negative onset potential for the formation of CH₄ than Cu(211). These onset potential trends for CO and CH₄ formations on Cu₇₉ NP, Cu(211), and Cu(111) are correlated with adsorption energetics of the key reaction intermediates including COOH, CO, and CHO. The insight may help improve the performance of Cu NPs for CO₂RR to CH₄.

中文翻译：

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对铜纳米颗粒上的电催化还原CO ₂到CH ₄的第一手见解

铜由于其在高超电势下生产烃的独特能力，已被广泛用于电催化CO ₂还原反应（CO ₂ RR）的研究。虽然CO ₂的结晶的Cu RR以Cu（211）和Cu的表面，例如（111）已被许多研究，CO的详细机械理解₂上小的Cu纳米粒子RR（NP）仍然缺乏。在这项工作中，我们使用Cu ₇₉作为代表NP，并通过第一性原理计算将其与Cu（211）和Cu（111）进行还原，以将CO ₂还原为CH ₄。计算出的自由能曲线表明，Cu ₇₉与Cu（211）和Cu（111）相比，NP表现出的CO形成的负起始电位都比Cu（211）小，但CH ₄的形成具有负起始电位。这些在Cu ₇₉ NP，Cu（211）和Cu（111）上形成CO和CH _4的潜在势能趋势与关键反应中间体（包括COOH，CO和CHO）的吸附能相关。洞察力可能有助于提高Cu NPs对CO ₂ RR转化为CH _4的性能。