[論文レビュー] Competing adsorption of H and CO on Pd-alloy surfaces: Mechanistic insight into the mitigating effect of Cu on CO poisoning

Pernilla Ekborg-Tanner, Paul Erhart|arXiv (Cornell University)|Feb 28, 2026

Catalysts for Methane Reforming被引用数 0

ひとこと要約

論文は水素と一酸化炭素がPd系合金表面上の吸着競合をどのように争うかを検討し、銅が機構的観点からCO中毒を低減する方法を説明します。

ABSTRACT

Multi-component alloys offer broad tunability for addressing challenges in materials science, but their vast configurational space makes their surface chemistry highly sensitive to operating conditions, for example through adsorption and segregation. Here, we study Pd-Au-Cu alloy surfaces in H$_2$ and CO environments motivated by their use in H technologies, in particular plasmonic H$_2$ sensing, where alloying can mitigate limitations intrinsic to Pd such as hysteresis and CO poisoning. Modeling multicomponent surfaces with multiple adsorbate species under realistic conditions is challenging. To this end, we establish an accurate and efficient framework that combines machine-learned interatomic potentials trained on density functional theory data to generate training data for cluster expansions with effectively no limitations on training set size. By constructing continuous surface phase diagrams for H-CO coadsorption we find that coadsorption under operating conditions is governed primarily by the H coverage during annealing. Au-rich surfaces, formed under H-poor conditions, suppress both CO and H adsorption, while H-rich conditions yield Pd-rich surfaces that maintain higher H coverages compared to Pd at relevant CO partial pressures, indicating improved CO poisoning resistance. This effect is insensitive to relative amounts of Au and Cu, despite experimental evidence of the mitigating effect of specifically Cu on CO poisoning. Kinetic barriers for dilute alloy surfaces indicate that absorption pathways near Au are highly unfavorable, while Cu leave the energetics unchanged compared to pure Pd. This finding suggests that Cu in the surface region provides viable pathways to shuttle H into the material when Pd-dominated paths are blocked by CO.

研究の動機と目的

• Pd-合金表面の吸着部位をHとCOがどう競合するかを理解する。
• CuがPd系触媒のCO中毒を緩和する役割を解明する。
• 触媒性能に関連する吸着挙動の機構的洞察を提供する。

提案手法

• 本文の抜粋には使用された方法は特定されていません。

実験結果

リサーチクエスチョン

• RQ1 Pd-合金表面におけるHとCOの吸着競合メカニズムは何か。
• RQ2 CuはPd系表面のCO中毒緩和にどのように影響するか。
• RQ3 CuがCO吸着の抑制効果を説明する機構的経路は何か。

主な発見

• CuがPd合金表面のCO中毒緩和に関する機構的洞察が議論されている。
• 触媒性能を理解するためにHとCOの競合吸着に焦点を当てている。
• 抜粋には具体的な定量的結果は提供されていない。