Theoretical study on the co-adsorption effect of H atoms on NH3 decomposition over Pt(100) and Pt(111) surfaces

IF 5 Q2 ENERGY & FUELS

Applications in Energy and Combustion Science Pub Date : 2025-07-25 DOI:10.1016/j.jaecs.2025.100358

Huanhuan Wang , Long Qin , Fanggang Zhang , Zaiqing Que , Ran Sui

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Abstract

The influence of co-adsorbed hydrogen (H) atoms on the decomposition of ammonia (NH₃) over two representative crystalline facets of platinum catalyst, i.e., Pt(100) and Pt(111), is investigated using density functional theory (DFT) and microkinetic modeling. The results reveal that NH₃ preferentially adsorbs on top sites, with its binding strength decreasing at higher coverages due to intermolecular repulsion. Although NH₃ adsorption is progressively unfavored on both facets with increased coverage by co-adsorbed H atoms, facet-dependent effects are observed: while Pt(100) maintains stable NH₃ decomposition energetics even at high H coverages, Pt(111) shows significant inhibition effect with increased reaction barriers and destabilized intermediates. Microkinetic simulations further confirm that Pt(100) exhibits superior catalytic activity, particularly in N–N coupling and N₂ desorption, compared to Pt(111). These findings highlight the critical role of surface structure and hydrogen coverage in modulating NH₃ decomposition kinetics, providing insights for optimizing Pt-based catalysts in NH₃-based energy systems.

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H原子对Pt（100）和Pt（111）表面NH3分解共吸附效应的理论研究

利用密度泛函理论（DFT）和微动力学模型研究了共吸附氢(H)原子对铂催化剂Pt（100）和Pt（111）两个代表性晶面上氨（NH3）分解的影响。结果表明，NH₃优先吸附在顶部位点上，由于分子间排斥，它的结合强度在更高的覆盖率下降低。尽管随着共吸附H原子覆盖率的增加，NH3的吸附在两个方面都逐渐变得不利，但观察到面依赖效应：即使在高H覆盖率下，Pt（100）也能保持稳定的NH3分解能量，而Pt（111）随着反应障碍和不稳定中间体的增加而表现出显著的抑制作用。微动力学模拟进一步证实，与Pt（111）相比，Pt（100）表现出更好的催化活性，特别是在N-N耦合和N2脱附方面。这些发现强调了表面结构和氢覆盖在调节NH3分解动力学中的关键作用，为优化NH3能源体系中基于pt的催化剂提供了见解。

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来源期刊

Applications in Energy and Combustion Science

CiteScore

4.20

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