Carbon dioxide (CO2) contributes to global warming and climate change, prompting countries to actively develop carbon reduction and negative carbon technologies. In response, the National Science and Technology Council (NSTC) established a task force in 2023 to promote Taiwan's net-zero technology initiatives, inviting domestic scholars and experts to jointly develop the forward-looking technologies required for achieving Taiwan's net-zero emissions by 2050. Supported by the NSTC's net-zero emission program, the NTU ZERO research and development team—composed of National Taiwan University Chemical Engineering Professors Dun-Yen Kang, Hsiu-Po Kuo, Chia-Wen Wu, Po-Yi Yu, and Chemistry professor Hao-Ming Chen—has successfully developed two pioneering technologies: "Membrane Carbon Capture" and "Electrochemical Carbon Conversion." Professor Hao-Ming Chen's electrochemical technology has established a pilot production machine capable of converting CO2 into formic acid or syngas, with a processing capacity of 50 kilograms of CO2 per day.
Taiwan's current energy supply mainly relies on fossil fuels such as coal, oil, and natural gas, with carbon emissions from thermal power generation accounting for about 14% of the nation's total carbon emissions. The industrial sector contributes approximately 55% of Taiwan's overall carbon emissions. Both sources can utilize carbon capture technology to capture CO2 from flue gas for reuse or storage. The most mature and widely adopted carbon capture technology in the industry uses ammonia solution and alkaline compounds as absorbents or adsorbents for CO2. However, this chemical absorption method requires heating for regeneration after the absorbent becomes saturated, which not only consumes energy but also indirectly generates additional CO2 emissions. According to estimates by Professor Po-Yi Yu's team, the carbon capture efficiency of the chemical absorption method is only about 60%, meaning that for every kilogram of CO2 captured, approximately 0.4 kilograms of additional emissions are generated.
Carbon Capture Technology
The NTU ZERO team is working to develop novel carbon capture and material technologies with the goal of improving CO2 capture efficiency. In terms of materials, Professor Chia-Wen Wu has developed innovative ultramicroporous metal-organic frameworks (MOFs) that selectively adsorb CO2 from the multiple components in flue gas (such as nitrogen, water vapor, and CO2) using the nanoscale cavities of the MOFs. Professor Hsiu-Po Kuo employs powder and chemical unit operation techniques to fabricate the MOF adsorbent into tubular forms and has set up mixed gas adsorption devices to test the CO2 adsorption efficiency. Professor Dun-Yen Kang has blended MOF materials with polymers to create membrane forms that can selectively remove CO2 from flue gas mixtures under continuous airflow conditions without the need for thermal regeneration. According to the team's calculations, the permeable membrane carbon capture technology has the potential to increase the carbon capture efficiency from 60% to about 90%, meaning that capturing each kilogram of CO2 would only result in 0.1 kilograms of additional emissions. Further calculations by the team suggest that replacing 10% of the current conventional chemical carbon capture methods in Taiwan with the novel membrane permeable carbon capture technology could reduce net CO2 emissions by approximately 5 million tons annually.
Electrochemical Carbon Conversion
Regarding CO2 reuse technology, Professor Hao-Ming Chen has developed a high-efficiency electrochemical process that can convert CO2 into syngas, formic acid, ethanol, or ethylene, which are upstream chemical products with negative carbon footprints. Its low energy consumption and high selectivity reduce the energy and costs required for subsequent product purification. Since it uses electricity as its energy source, it can easily integrate with renewable energy, promoting better environmental friendliness and sustainability. Importantly, during the conversion process, CO2 can be transformed into high-value chemical raw materials, addressing the issue of carbon emissions while creating new economic value. This approach not only revitalizes carbon that would otherwise be treated as waste but also mitigates high treatment costs, thereby creating a new market for negative carbon chemicals.
Currently, the global progress in electrochemical CO2 conversion is still limited to laboratory-scale single reactors or simple electrochemical stack modules, far from practical application in real-world settings. The industrial concept machine presented here introduces programmable automatic control to achieve automated regulation of process conditions. Additionally, it incorporates mechatronic integration of human-machine interfaces, elevating the small modules that previously existed only in laboratories to an industrial level. It further implements a low-energy, high-value anode system that overcomes the high-energy consumption limitations of traditional electrochemical systems, reducing energy consumption to only 60% of traditional methods while increasing commercial viability. Initially, the tabletop electrolytic device could handle 0.2 kilograms of CO2 per day, while the first-generation small prototype handled 3 kilograms per day. The current industrial prototype can process 50 kilograms of CO2 daily.
In response to the global focus on carbon capture, the NTU ZERO team has developed highly innovative next-generation carbon capture and reuse technologies that are expected to be implemented in the industry. The membrane carbon capture technology significantly reduces the energy consumption and secondary carbon emissions associated with carbon capture, while the electrochemical technology enables the conversion of CO2 into the key upstream chemical product. This, in comparison to carbon storage, facilitates the synthesis of higher-value specialty chemical. Under the leadership of NTU's innovative technologies, it is hoped that more domestic industries will invest in this initiative to work together towards Taiwan's vision of achieving net-zero carbon emissions.
Media Contact:
Ching-An Chuang
Program Manager
Department of Engineering and Technologies
National Science and Technology Council
Tel: +886 (2) 27377372
E-mail: cchuang2@nstc.gov.tw