Studi Teori Fungsional Kerapatan pada Penentuan Jalur Reaksi Pemecahan H2O di Atas Permukaan PtMo(111)

Dian Bayuaji, Wahyu Tri Cahyanto, R. Farzand Abdullatif

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Abstrak – Telah dilakukan penelitian terkait simulasi kuantum untuk pemecahan molekul air (H2O) pada permukaan PtMo(111) berbasis Density Functional Theory (DFT).  Penelitian ini dilakukan untuk mengetahui jalur reaksi yang paling efektif dalam proses pemecahan H2O dan mekanisme reaksinya.  Hasil perhitungan menunjukkan bahwa jalur yang paling mungkin  untuk pemecahan H2Oads menjadi Hads dan OHads adalah pergerakan H dari posisi H2O di top Mo2 ke situs HCP Pt41-Mo2-Pt42, dilanjutkan ke situs FCC Pt42-Mo2-Pt46, kemudian ke situs bridge Pt42-Pt46, terus ke situs HCP Pt42-Pt43-Pt46, dan berakhir di situs FCC Pt38-Pt42-Pt43. Posisi OHads berada di top Mo2. Adapun energi aktivasi yang diperlukan untuk memecah H2O sebesar 0,68 eV.  Selanjutnya, mekanisme reaksi pemecahan H2O dibahas dengan analisis struktur geometri dari adsorpsi H2O di situs yang bersesuaian dengan jalannya reaksi.

Kata kunci: pemecahan H2O, DFT, PtMo(111), energi aktivasi, mekanisme reaksi

Abstract – Quantum simulation studies for the decomposition of water molecules (H2O) on the surface of PtMo (111) based on the density functional theory (DFT) were performed.  This study was conducted to determine the most preferred pathways of the H2O dissociation process and its reaction mechanism.  The calculation results show that the most preferential pathway to decompose H2Oads into Hads and OHads is the movement of H from the original position of adsorbed H2O atop Mo2 to the HCP Pt41-Mo2-Pt42 site, then to the FCC Pt42-Mo2-Pt46 and then to the bridge site of neighboring Pt42-Pt46 atoms followed by HCP Pt42-Pt43-Pt46 site and terminate at the FCC Pt38-Pt42-Pt43 site.  The position of OHads remains on top of Mo2.  The activation energy required to break H2O is 0.68 eV.  In addition, the reaction mechanism for H2O dissociation is discussed by analyzing the adsorption geometriy corresponding to the each sites of reaction paths.

Key words: dissociation of H2O, DFT, PtMo(111), activation energy, reaction mechanism

Kata Kunci


pemecahan H2O, DFT, PtMo(111), energi aktivasi, mekanisme reaksi

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Referensi


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DOI: https://doi.org/10.35895/rf.v3i2.156

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