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Electrochemical CO2/CO Conversion & EC Fischer–Tropsch

첨단 촉매·전기화학 기법으로 CO2와 CO를 고부가가치 연료(메탄, 메탄올, 다탄소 생성물)로 재자원화합니다. 동적 촉매 계면에서의 전기화학적 C–C 사슬 성장, 즉 EC Fischer–Tropsch 합성을 개척합니다.

Keywords

CO2RR · CORR · Electrocatalysis

Electrochemical CO2/CO Conversion & EC Fischer–Tropsch

대표 논문

  • 1

    Electrochemical Fischer-Tropsch chemistry across transition metals: A paradigm shift in sustainable liquid fuel production

    Seon Young Hwang; Ju Young Maeng; Ilsun Yoon; Chang Woo Myung; Choong Kyun Rhee; Youngku Sohn

    Nano Energy 2024, 128, 109881. DOI ↗ 📊 인용 ↗

    📄 초록 ▾

    본 연구는 전통적인 고에너지 소모 공정에서 벗어난 친환경 액체 연료 생산법으로 전기화학적 Fischer-Tropsch(EC F-T) 합성을 탐구하였다. 전기화학적 합성가스 생성은 충분히 연구되어 있지만, CO2와 CO 공급 기체를 이용한 F-T 화학 합성은 상대적으로 연구가 부족하다. Ti, Zr, V, Mo, Fe, Co, Ni, Pd, Cu, Ag, Au, Zn 및 Cd를 포함한 여러 전이금속을 조사한 결과, Zn을 제외한 금속에서 장쇄 탄화수소(CnH2n 및 CnH2n+2, n=2-7)를 생성하는 F-T 화학의 명확한 증거를 제시하였다. 이 과정은 전통적 F-T 합성과 유사한 표면 C-C 결합 사슬 성장을 포함하며, *CO 및 *CHx 삽입 반응이 관여한다. 페르미 준위 부근의 상태 밀도와 에너지 준위도 분석하였다. 이 실험 체계는 C-C 결합 기작에 대한 이해를 높이고, 장쇄 탄화수소 생산을 위한 친환경 전기화학 방법에 통찰을 제공하며, 미래 에너지 해결책을 위한 지속 가능한 F-T 합성의 혁신 전략을 발전시킨다.

    ※ 연구실에서 옮긴 비공식 번역입니다. 정확한 표현은 원문·DOI를 확인해 주세요.

    원문 (English) ▾

    This study explores electrochemical Fischer-Tropsch (EC F-T) synthesis as an eco-friendly approach for liquid fuel production, departing from conventional energy-intensive methods. While EC syngas generation is wellexplored, the synthesis of F-T chemistry using CO2 and CO feed gases remains relatively unexplored. Investigating various transition metals, including Ti, Zr, V, Mo, Fe, Co, Ni, Pd, Cu, Ag, Au, Zn, and Cd, we present compelling evidence of F-T chemistry, yielding long-chain hydrocarbons (CnH2n and CnH2n+2, n=2–7), with Zn being an exception. This breakthrough involves surface C-C coupling chain growth, resembling traditional F-T synthesis, incorporating *CO and *CHx insertion reactions. Density of states and energy states near the Fermi level were analyzed. The experimental framework enhances our understanding of C-C coupling mechanisms, offering insights into environmentally friendly EC methods for long-chain hydrocarbon production and advancing innovative strategies in sustainable F-T synthesis for future energy solutions.

  • 2

    Exploring Direct Electrochemical Fischer–Tropsch Chemistry of C1–C7 Hydrocarbons via Perimeter Engineering of Au–SrTiO3 Catalyst

    Ju Hyun Yang; Gi Beom Sim; So Jeong Park; Choong Kyun Rhee; Chang Woo Myung; Youngku Sohn

    Adv. Energy Mater. 2024, 14, 2402062. DOI ↗ 📊 인용 ↗

    📄 초록 (English) ▾

    Traditionally, Fischer–Tropsch (FT) synthesis is performed using thermal catalysts and syngas (CO and H 2 ) under high‐pressure and high‐temperature conditions. However, this study introduces an approach that relies on FT chemistry assisted by electrochemistry, referred to here as direct electrochemical (EC) FT chemistry, under ambient conditions. A series of CH 4 , C n H 2n , and C n H 2n+2 hydrocarbons (n = 1–7) is successfully produced over gold (Au) nanoparticle‐loaded perovskite strontium titanate (SrTiO 3 ) nanostructures grown on rutile TiO 2 supported on Ti. Au (1.0 nm)–SrTiO 3 shows the best interface formation, with the highest Faradaic efficiency for C 2+ hydrocarbons. This direct EC‐FT process proceeds via a C─C coupling chain growth reaction at the Au‐SrTiO 3 interface as evidenced by the hydrocarbon weight distribution analysis and density functional theory calculations. The robust combination of experimental and computational findings reveals that optimum conditions for producing surface hydrogenation and C─C coupling polymerization, initiated by surface * CO and * H are achieved by controlling the undercoordinated Au at the perimeter sites of supported Au nanoparticles and by ensuring a harmonized density of states between Au and SrTiO 3 . This EC‐FT process opens a promising avenue for the direct conversion of CO 2 and H 2 O into value‐added long‐chain hydrocarbons.

  • 3

    Unlocking long-chain hydrocarbons (C2–7) via direct electrochemical CO2 and CO reduction on balanced Au/Ni electrodes

    Young Jun Kim; Ju Young Maeng; Seon Young Hwang; Ju Hyun Yang; Ilsun Yoon; Chang Woo Myung; Choong Kyun Rhee; Youngku Sohn

    Nano Energy 2023, 118, 108995. DOI ↗ 📊 인용 ↗

    📄 초록 ▾

    전기화학적(EC) 이산화탄소 환원법은 녹색에너지 및 환경 문제 해결 전략으로 널리 활용되어 왔다. 본 연구에서는 직접 전기화학적 Fischer-Tropsch(dEC F-T) 합성 경로라는 새로운 개념을 보여주기 위해 Au/Ni 전극을 사용하였다. 이 경로는 EC CO2 환원 중 H2와 CO, 즉 합성가스를 만드는 전극 특성을 결합한다. Ni 전극 표면에 Au를 도입하자 CO 생산은 증가하고 H2 생산은 점차 감소하였다. 계면의 균형이 맞았을 때 뚜렷한 F-T 합성 경로가 나타나 일련의 탄화수소(CnH2n 및 CnH2n+2, n=2-7)가 생성되었다. dEC F-T 합성은 전해질, 농도, 금속 지지체(Co와 Fe), 여러 표면층 금속(Ag와 Cu), 광조사 및 동위원소 효과 등 다양한 조건에서 평가하였다. 앤더슨-슐츠-플로리 질량 분포 분석을 바탕으로 표면 C-C 결합 중합 반응을 통해 공정을 설명하였다. 또한 CO와 H의 직접 흡착을 이용한 EC CO 환원에서도 F-T 합성을 입증하였다. dEC F-T 경로는 고부가가치 장쇄 탄화수소를 생산하여 에너지 및 환경 문제를 해결할 수 있는 새로운 전략을 제공한다.

    ※ 연구실에서 옮긴 비공식 번역입니다. 정확한 표현은 원문·DOI를 확인해 주세요.

    원문 (English) ▾

    Electrochemical (EC) CO2 reduction method has been widely used as a green energy and environmental solution strategy. The use of Au/Ni electrodes was introduced to showcase a new concept of the direct EC Fischer-Tropsch (dEC F-T) synthesis pathway. This pathway involves the combination of electrodes that produce H2 and CO (syngas) during electrochemical CO2 reduction. The introduction of Au on the Ni electrode surface led to an increase in CO production and a gradual decrease in H2 production. When the interface was balanced, a pronounced F-T synthesis pathway was observed, resulting in the production of a series of hydrocarbons (CnH2n and CnH2n+2, n = 2–7). The dEC F-T synthesis was evaluated under different conditions, including electrolytes, concentrations, metal supports (Co and Fe), various overlayer metals (Ag and Cu), light irradiation, and isotope effects. The process was elucidated through surface C-C coupling polymerization reactions based on Anderson-Schulz-Flory weight distribution analysis. Additionally, the F-T synthesis was demonstrated through EC CO reduction via direct CO and H adsorption. The dEC F-T path provides a novel strategy for energy and environment by producing high-value long-chain hydrocarbons.

  • 4

    Electrochemical reduction of CO2 and CO using interface-engineered Au/Ti electrodes for long-chain hydrocarbon production

    Young Jun Kim; Ju Young Maeng; Seon Young Hwang; Choong Kyun Rhee; Youngku Sohn

    Appl. Catal. B 2023, 338, 123017. DOI ↗ 📊 인용 ↗

    📄 초록 ▾

    본 연구는 계면 공학으로 제조한 Au/Ti 전극을 사용한 CO2 및 CO의 전기화학적 환원을 보여준다. 표면 CO 형성 경로로 CO의 직접 흡착과 CO2 조건에서의 간접 과정이 제안되었다. 표면 H는 H+/H2O로부터 형성되었다. 표면 CO와 H 사이의 Fischer-Tropsch 합성을 모사하여 CH4와 탄화수소(CnH2n 및 CnH2n+2, n=2-7)를 생산하였다. CO의 패러데이 효율은 Au 피복률이 증가할수록 높아져 38%에 도달하였다. CO2로 포화된 KHCO3에서는 Au 피복률이 낮은 Au/Ti 전극에서 장쇄 탄화수소가 생성되었다. CO2 및 CO로 포화된 인산염 전해질에서는 Au 피복률이 높을수록 장쇄 탄화수소 생산량이 증가하였다. 알케인/알켄 비는 Au 피복률이 증가할수록 높아졌지만 인가 전위가 커질수록 낮아졌다. 이 연구는 계면 공학, 전기화학적 장쇄 탄화수소 생산 및 C-C 결합 기작에 관한 통찰을 제공한다.

    ※ 연구실에서 옮긴 비공식 번역입니다. 정확한 표현은 원문·DOI를 확인해 주세요.

    원문 (English) ▾

    This study demonstrates the electrochemical reduction of CO2 and CO using interface-engineered Au/Ti electrodes. Direct adsorption of CO and indirect processes in CO2 conditions were proposed to form surface CO. Surface H was formed from H+/H2O. Mimicking Fischer-Tropsch synthesis between surface CO and H resulted in the production of CH4 and hydrocarbons (CnH2n and CnH2n+2, n = 2–7). Faradaic efficiency of CO increased with increasing Au coverage and reached 38%. In CO2-saturated KHCO3, long-chain hydrocarbon production was observed on Au/Ti electrodes with low Au coverage. In CO2 and CO-saturated phosphate electrolytes, higher Au coverage resulted in higher production of long-chain hydrocarbons. The ratio of alkanes to alkenes increased with increasing Au coverage but decreased with applied potential. The study provides insights into interface engineering, electrochemical long-chain hydrocarbon production, and C-C coupling mechanisms.

  • 5

    Opening Direct Electrochemical Fischer–Tropsch Synthesis Path by Interfacial Engineering of Cu Electrode with P-Block Elements

    Ju Hyun Yang; Seon Young Hwang; Ju Young Maeng; Go Eun Park; Seo Young Yang; Choong Kyun Rhee; Youngku Sohn

    ACS Applied Materials & Interfaces 2024, 16, 3368-3387. DOI ↗ 📊 인용 ↗

    📄 초록 (English) ▾

    The electrochemical synthesis of syngas (CO and H 2 ) has garnered considerable attention in the context of Fischer–Tropsch (FT) synthesis employing thermal catalysts. Nonetheless, the need for a novel, cost-effective technique persists. In this investigation, we introduce a direct electrochemical (dEC) approach for FT synthesis that functions under ambient conditions by utilizing a p-block element (Sn and In) overlaid Cu electrode. Surface *CO and H* species were obtained in an electrolytic medium through the CO 2 + H + + e – → HOOC ad → *CO (or direct CO adsorption) and H + + e – → H* reactions, respectively. We have observed C 2–7 long-chain hydrocarbons with a C n H 2 n +2 /C n H 2 n ratio of 1–3, and this observation can be explained through the process of C–C coupling chain growth of the conventional FT synthesis, based on the linearity of the Anderson-Schulz–Flory equation plots. Thick Sn and In overlayers resulted in the dominant production of formate, while CO and C 2 H 4 production were found to be proportional and inversely correlated to H 2, C 2 H 6, and C 3–7 hydrocarbon production. The EC CO 2 /CO reduction used in dEC FT synthesis offers valuable insights into the mechanism of C 2+ production and holds promise as an eco-friendly approach to producing long-chain hydrocarbons for energy and environmental purposes.

  • 6

    Electrochemical CO2/CO reduction on Ag/Cu electrodes and exploring minor Fischer–Tropsch reaction pathways

    Gaeun Yun; Seon Young Hwang; Ju Young Maeng; Young Jun Kim; Choong Kyun Rhee; Youngku Sohn

    Appl. Surf. Sci. 2024, 649, 159179. DOI ↗ 📊 인용 ↗

    📄 초록 ▾

    Ag/Cu 하이브리드는 전기화학적(EC) CO2 환원에서 효율이 높고 우수한 C-C 결합 생성물을 만드는 촉매로 부상하였다. 본 연구에서는 스퍼터 증착으로 제조한 Ag/Cu 전극을 사용하여 EC CO2 및 CO 환원 가능성을 조사하였다. Ag 두께는 생성되는 기체 및 액체 생성물에 큰 영향을 미쳤으며, Ag/Cu 계면이 핵심 역할을 하였다. CO2 포화 조건에서는 CO, CH4 및 C2H4가 높은 패러데이 효율로 생성되었고, CO2로 포화된 KHCO3에서는 폼산염, 에탄올, 프로판올, 아이소프로판올, 아세트산염 및 아세톤이 생성되었다. 인산염 조건에서는 Fischer-Tropsch 화학의 전형적 생성물인 장쇄 탄화수소(CnH2n 및 CnH2n+2, n=2-7)로 이어지는 새로운 경로가 확인되었다. 또한 CO 수소화를 통해 CH4 및 C2-7 탄화수소가 생성됨을 보였으며, 알케인/알켄 비는 전해질의 종류와 농도, 인가 전위 및 Ag로 개질된 Cu에 따라 달라졌다. 이 결과는 에너지와 환경 응용뿐 아니라 C-C 결합을 통한 EC CO2 및 CO 환원의 발전에 시사점을 제공한다.

    ※ 연구실에서 옮긴 비공식 번역입니다. 정확한 표현은 원문·DOI를 확인해 주세요.

    원문 (English) ▾

    Ag/Cu hybrids have emerged as highly efficient catalysts for electrochemical (EC) CO2 reduction, yielding impressive C–C coupling products. We investigate Ag/Cu electrodes prepared via sputter deposition to explore their potential in EC CO2 and CO reductions. Our study highlights the significant impact of Ag thickness on resulting gas and liquid products, emphasizing the vital role of the Ag/Cu interface. Under CO2-saturated conditions, CO, CH4, and C2H4 are produced with high Faradaic efficiencies, while CO2-saturated KHCO3 generates formate, ethanol, propanol, isopropanol, acetate, and acetone. Experiments in phosphate conditions reveal new pathways for long-chain hydrocarbons (CnH2n and CnH2n+2, n = 2–7), typical products of Fischer-Tropsch chemistry. We also demonstrate CO hydrogenation to CH4 and C2-7 hydrocarbons, with alkane/alkene ratios influenced by electrolyte nature, concentration, applied potential, and Ag-modified Cu. These insights have implications for energy, environmental applications, and the future of EC CO2 and CO reduction through C–C coupling.