Malaysian Journal of Analytical Sciences Vol 26 No 3 (2022): 664 - 683

 

 

 

 

ENHANCING THE OXYGEN REDUCTION REACTION OF LOW-PLATINUM AND NON-PLATINUM CATALYSTS FOR FUEL CELL APPLICATIONS

 

(Peningkatan Tindak Balas Penurunan Oksigen Mangkin Platinum Bermuatan Rendah dan Bebas Platinum Untuk Aplikasi Sel Bahan Api)

 

Kazi Rumanna Rahman¹, Kuan Ying Kok², Nor Azillah Fatimah Othman³, Wai Yin Wong¹, Kean Long Lim¹*

 

¹Fuel Cell Institute,

Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

² Industrial Technology Division

³Radiation Processing Technology Division

Malaysia Nuclear Agency, 43000, Kajang, Selangor, Malaysia

 

*Corresponding author email:  kllim@ukm.edu.my

 

 

Received: 13 December 2021; Accepted: 6 March 2022; Published:  27 June 2022 

 

 

Abstract

Nowadays, research efforts are focused on developing low-Pt and non-Pt catalysts for ORR. The addition of Pt-group metal (PGM) in pure Pt to form Pt-PGM catalysts exhibits better ORR performance than pure PGM catalysts and Pt/C. More than 20 wt.% of Pt loading is required in Pt-PGM alloys for improving catalytic activity. Studies have also shown that the addition of transition metal (TM), which has a smaller atomic size, into PGM reduced the bond distance between two metallic atoms and geometric parameters, thus remarkably improving the catalytic stability and ORR activity. However, TM based catalysts should be supported on nitrogen-doped carbon with high surface area to attain high ORR activity. A large surface area and high electronic conductivity of carbon support also facilitate the ORR activity. Performances of alloy catalysts are directly related to their synthesis temperature and structural properties. Designing the core-shell combinations and controlling the shell thickness is one of the structural strategies in enhancing mass activity and durability. Lately, irradiation techniques are used to modify the physicochemical properties. Nevertheless, TM-based catalysts are usually stable in alkaline solutions but not in acidic solutions. This review focuses on the strategies to develop cost-effective catalysts from low-platinum and non-platinum catalysts with enhanced ORR activity.

 

Keywords:  oxygen reduction reaction, platinum group metal alloys, transition metal catalysts, synthesis techniques 

 

Abstrak

Pada masa kini, usaha penyelidikan tertumpu kepada pembangunan mangkin platinum (Pt) bermuatan rendah dan bebas platinum untuk tindak balas penurunan oksigen (ORR). Penambahan logam kumpulan Pt (PGM) dalam Pt tulen untuk membentuk Pt-PGM menunjukkan prestasi ORR yang lebih baik daripada prestasi mangkin PGM tulen dan Pt/C. Sebanyak lebih daripada 20 wt.% muatan Pt adalah diperlukan dalam aloi Pt-PGM untuk meningkatkan aktiviti pemangkinan. Kajian telah menunjukkan penambahan logam peralihan (TM) yang mempunyai saiz atom yang lebih kecil ke dalam PGM mengurangkan jarak antara dua atom logam dan parameter geometri sekali gus meningkatkan kestabilan pemangkinan dan aktiviti ORR. Namun demikian, mangkin berasakan TM perlu disokong dengan karbon terdop nitrogen yang berpermukaan yang luas untuk mencapai aktiviti ORR yang tinggi. Penyokong karbon yang berpemukaan luas dan mempunyai kekonduksian elektronik yang tinggi juga memudahkan   aktiviti ORR. Prestasi mangkin aloi adalah berkait langsung dengan suhu sintensi dan sifat strukturnya. Mereka bentuk gabungan teras-cangkerang dan mengawal ketebalan cangkerang adalah salah satu strategik penstrukturan dalam meningkatkan aktiviti jisim dan ketahanan. Akhir-akhir ini, teknik-teknik penyinaran digunakan ubah mengubahsuai sifat fizikokimia. Namun demikian, mangkin berasaskan TM biasanya stabil dalam larutan alkali tetapi tidak dalam larutan asid. Ulasan ini berfokus pada strategik untuk membangunkan magkin berkos efektif daripada mangkin Pt bermuatan rendah dan bebas platinum dengan aktitiviti ORR yang dipertingkatkan.

 

Kata kunci:  tindak balas penurunan oksigen, logam aloi kumpulan platinum, mangkin logam peralihan, kaedah sintesis

 

 

Graphical Abstract

 

 

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