Peran oksigen dan air di dalam nanocluster molybdenum

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Referensi:
Howalt J.G., Vegge T. (2014). The role of oxygen and water on molybdenum nanoclusters for electro catalytic ammonia production. Beilstein J. Nanotechnol., 5: 105-110.

Air berperan di dalam meningkatkan absorpsi oksigen pada permukaan katalis melalui penguraian air dan oksigen atau hidrogen terlarut sering memenuhi permukaan yang penting, sehingga menyebabkan turunnya hambatan total dari reaksi-reaksi kimia lain yang terjadi pada permukaan tersebut. Penelitian ini mengamati pengaruh absorpsi dan reduksi oksigen terhadap katalis elektro nanocluster molybdenum yang dicakup oleh nitrogen untuk reduksi elektrokimia N2 menjadi NH3. Tujuan dari penelitian adalah memahami pencampuran hidrogen dan air pada katalis. Peneliti menggunakan perhitungan-perhitungan teori fungsional kerapatan digabungkan dengan pendekatan elektroda hidrogen berbasis komputer untuk menghitung profil energi bebas untuk protonasi elektrokimia spesies O dan N2 pada nanocluster Mo13 cuboctahedral. Perhitungan menunjukkan bahwa nanocluster molybdenum akan lebih mengikat oksigen daripada nitrogen dan hidrogen pada bias netral, namun di dalam kondisi reaksi elektrokimia yang dibutuhkan untuk reduksi nitrogen, absorpsi oksigen akan sangat lemah dan energi absorpsinya akan sebanding dengan absorpsi hidrogen dan nitrogen. Potensi yang diperlukan untuk mereduksi oksigen dari permukaan adalah -72 V atau lebih rendah untuk semua oksigen yang diamati, dan oleh karena itu terjadi kemungkinan untuk (re)aktivasi (sebagian) nanocluster oksigen untuk produksi ammonia elektrokimia, misalnya, dengan menggunakan konduktir proton kering atau elektrolit cair. Pada cakupan oksigen yang rendah molekul-molekul nitrogen dapat melakukan absorpsi pada permukaan dan produksi ammonia elektrokimia melalui mekanisme asosiatif akan dimungkinkan pada potensial -0,45-0,7 V.
SJR Impact Factor - Bellstein Journal of Nanotechnology: SCImago Journal & Country Rank

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