Sains Malaysiana 54(8)(2025): 2059-2074

http://doi.org/10.17576/jsm-2025-5408-15

 

Formulasi Pemangkin Stanum-Kuprum untuk Penurunan CO₂ Elektrokimia dalam Sel Elektrosintesis Mikrob

(Formulation of Copper-Tin Catalyst for Electrochemical CO₂ Reduction in Microbial Electrosynthesis Cells)

 

IRWAN IBRAHIM¹, AMIRUL AIMAN RIO HENDRY², MIMI HANI ABU BAKAR¹, MANAL
ISMAIL^1,3, KEE SHYUAN LOH¹ & SWEE SU LIM^1,*

 

¹Institut Sel Fuel (SELFUEL), Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

²Fakulti Kejuteraan Awam, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia

³Jabatan Kejuruteraan Kimia dan Proses, Fakulti Kejuruteraan dan Alam Bina, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia

 

Diserahkan: 11 Januari 2025/Diterima: 3 Julai 2025

 

ABSTRAK

Proses penurunan CO₂ menggunakan pendekatan bio-elektrokimia merupakan satu bidang yang masih baharu dalam dunia kajian. Sistem Mikrob Elektrosintesis (SME) merupakan sistem bio-elektrokimia yang menggunakan mikrob elektrogenik, iaitu mikrob yang menggunakan elektrik sebagai tenaga untuk proses penurunan Karbon Dioksida (CO₂) dalam menghasilkan sebatian kimia. Kajian ini mengguna pakai SME untuk menghasilkan asid formik menggunakan mikrob elektrogenik. Proses ini dipercepatkan lagi menggunakan pemangkin bio-katod yang diubah suai melalui proses penyaduran elektrokimia untuk menambah lapisan kuprum-stanum oksida di atas permukaan kain karbon. Kuprum dan stanum merupakan logam yang dikenal pasti mampu meningkatkan kadar tindak balas penurunan CO₂ kepada sebatian yang bersifat hidrokarbon, iaitu formik dalam kajian ini. Melalui kajian yang dijalankan yang terdiri daripada Cu-Sn-EDTA, Cu-Sn-Sb-EDTA, Cu-Sn-NaCit dan Cu-Sn-Sb-NaCit, sebatian Cu-Sn-EDTA telah dikenal pasti menggunakan FESEM-EDX menunjukkan struktur kristal berbentuk bunga yang terbentuk melalui tindak balas nukleasi dengan taburan aloi gangsa yang agak seimbang. Dengan mengaplikasi katod komposit tersebut ke sistem SME telah menunjukkan penghasilan ketumpatan arus dan purata voltan yang stabil dan tertinggi pada -19.14 A/cm² dan -0.49 V dan kadar penghasilan formik sehingga 0.137 M/d. Analisis kitaran voltametri sel penuh pula menunjukkan Cu-Sn bio katod mencatatkan puncak penurunan yang terendah pada voltan -1.0 V, iaitu bersamaan dengan voltan gunaan semasa operasi SME.

Kata kunci: Mikrob elektrosintesis; pemangkin kuprum-tin; penghasilan asid formik; penurunan elektrokimia CO₂; sistem bioelektrokimia

 

Abstract

The CO₂ reduction process using a bioelectrochemical approach is a novel field of study. The Microbial Electrosynthesis (MES) system is a type of bioelectrochemical system that utilizes electrogenic microbes, microorganisms that use electricity as an energy source, to reduce carbon dioxide (CO₂) and produce chemical compounds. This study applies MES to produce formic acid using electrogenic microbes. The process is further accelerated by a modified biocathode catalyst, created through an electrochemical deposition process to form a copper-tin oxide layer on the surface of carbon cloth. Copper and tin are metals known to enhance the rate of CO₂ reduction into hydrocarbon-based compounds, specifically formic acid in this study. Among the tested materials - CuSn-EDTA, CuSnSb-EDTA, CuSn-NaCit, and CuSnSb-NaCit - CuSn-EDTA was identified through FESEM-EDX analysis to exhibit a flower-shaped crystalline structure formed via nucleation, with relatively uniform bronze alloy distribution. The application of this composite cathode in the MES system demonstrated the highest and most stable current density and average voltage, at -19.14 A/cm² and -0.49 V, respectively, and achieved a formic acid production rate of up to 0.137 M/d. Full-cell cyclic voltammetry analysis showed that the CuSn biocathode recorded the lowest reduction peak voltage at -1.0 V, consistent with the operating voltage used in the MES process.

Keywords: Bioelectrochemical systems; copper-tin catalyst; electrochemical CO₂ reduction; formic acid production; microbial electrosynthesis

 

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*Pengarang untuk surat-menyurat; email: limss@ukm.edu.my