Periodic Reporting for period 1 - HPSR-AME-CO2RR (Combining catalyst design and electrode reconstruction for industry compatible CO2 electrolysis)
Reporting period: 2024-06-01 to 2026-05-31
Anthropogenic CO2 emission is anticipated to contribute to a projected global temperature increase of 1.5°C between 2030 and 2052, which is associated with various environmental challenges. While renewable energy sources and electrification have successfully reduced CO2 emissions in some sectors, air transportation without available electrified alternatives and sectors like steel and cement production that inherently involve carbon oxidation in operations must proactively take measures to mitigate their carbon footprint. This entails a combination of adopting renewable fuels and employing CO2 conversion techniques. In the short to intermediate term, the renewable-powered electrochemical CO2 reduction reaction (eCO2RR) for carbon monoxide production offers a techno-economically feasible approach. Despite extensive research efforts in this field, achieving economically compelling eCO2RR implementation has proven elusive. The primary challenges stem from catalyst performance and electrode durability. Regarding catalysts, maintaining high selectivity under commercially relevant conditions is imperative. On the electrode front, enhancing both chemical and mechanical strength is essential to reduce capital expenditure. To comprehensively address these challenges, this project aims to integrate electrocatalyst design (focused on improving eCO2RR selectivity and activity) with electrode reconstruction efforts (aimed at overcoming flooding issues and enhancing the stability of the reaction interface). This integrated approach seeks to facilitate the practical implementation of eCO2RR. Furthermore, a deep understanding of the structure-activity relationship will be attained through in-situ spectroscopy and theoretical calculations. The assessment of this novel strategy within this project's scope has the potential to guide the more rational development of practical eCO2RR implementation.
The objective of this project is to construct a novel 3D self-supporting aerogel monolithic electrode (AME) accommodating high-density single atom catalysts (SACs) for achieving an overall enhancement of jCO at a low overpotential, stability, and SPC, thus, optimizing EE to meet the requirements at a real-world scale. This is accomplished by a hierarchical porous structure reconstruction strategy (HPSR).
The objective of this project is to construct a novel 3D self-supporting aerogel monolithic electrode (AME) accommodating high-density single atom catalysts (SACs) for achieving an overall enhancement of jCO at a low overpotential, stability, and SPC, thus, optimizing EE to meet the requirements at a real-world scale. This is accomplished by a hierarchical porous structure reconstruction strategy (HPSR).
Work Performance:
WP1: Synthesis of high-metal-loading SACs 3D AME.
WP2: Optimization of the eCO2 RR performance on SACs/3D AME electrode.
WP3: Characterization of the high-loading SACs and 3D AME.
WP4: Mechanistic study conversion pathways on optimized SACs and AME.
Main Achievement:
1. Successful preparation of N-doped carbon substrate with a large surface area
2. Achievement of high catalytic performance on prepared N-doped carbon material in comparison of other counterparts
3. Finish the publication
4. Successful synthesis of high-metal loadings on prepared N-doped carbon substrate
5. Finish the catalytic performance on prepared Fe SAC
6. Loading the Fe SAC on the designed 3D substrate
WP1: Synthesis of high-metal-loading SACs 3D AME.
WP2: Optimization of the eCO2 RR performance on SACs/3D AME electrode.
WP3: Characterization of the high-loading SACs and 3D AME.
WP4: Mechanistic study conversion pathways on optimized SACs and AME.
Main Achievement:
1. Successful preparation of N-doped carbon substrate with a large surface area
2. Achievement of high catalytic performance on prepared N-doped carbon material in comparison of other counterparts
3. Finish the publication
4. Successful synthesis of high-metal loadings on prepared N-doped carbon substrate
5. Finish the catalytic performance on prepared Fe SAC
6. Loading the Fe SAC on the designed 3D substrate
Augmenting mesopores can enhance the accessibility of active sites and facilitate the mass transport of eCO2RR-relevant intermediates. Mesopore augmentation can surpass the atomic-scale modulation of the active sites, demonstrating superior activity compared to nonporous counterparts. Also, creating abundant porosity in catalysts can suppress the HER by influencing the local alkalinity near the active sites. For instance, accumulating hydroxide ions at the interface between the catalyst and the electrolyte (CO2 + H2O + 2e− → CO + 2OH−) during eCO2RR limits the competing HER.
Nevertheless, the advancement of mesopore construction strategies in N-C materials still faces significant challenges in establishing the performance-structure relationship. This challenge stems from the fact that introducing mesopores usually alters the active sites or the chemical composition of the catalysts, adding further complexity to the investigation of porosity-induced performance in N-C materials. As a result, the interaction between porosity modifications and variations in active sites complicates understanding the performance-structure correlation in N-C materials. Evidently, maintaining consistency in the types of active sites and their immediate surroundings would facilitate a clearer understanding of the contribution of distinct pore types to the conversion of CO2 to CO. The aim of our study is to isolate the augmented porosity from other alterations in the catalysts' composition, allowing the impact of increased mesopore content in N-C materials to be studied on both the selectivity and activity of eCO2RR.
I present a strategy for enhancing the mesopore content in N-C materials derived from metal-organic frameworks (MOFs) by incorporating additional carbon sources to improve the catalytic performance of eCO2RR. Specifically, we used isoreticular MOF (i.e. IRMOF 3), with a pore size diameter of 1.5 nm, as the precursor for the carbon matrix. To prevent structural collapse and preserve porosity during the subsequent carbonization process, N-rich monomers containing O [furfuryl alcohol (FA)], known for its polycondensation properties, was introduced into the IRMOF-3 cavities through nanocasting as an additional carbon source, creating the FA-IRMOF-3 composite material. Therefore, after pyrolysis, we successfully designed two N-C catalyst materials featuring varying mesopore content with an average pore size of ~10 nm. The careful nanocasting process preserved the types and content of active sites and the size of catalysts, selectively enhancing the mesopore content in the resulting N-C catalyst (referred to as P-N-C). As a result, the P-N-C material continuously maintained a high FECO (>90%) and outperformed N-C and P-O-C across the entire potential window. Meanwhile, this substrate provides a large-surface-area substrate for the next SAC loading.
Nevertheless, the advancement of mesopore construction strategies in N-C materials still faces significant challenges in establishing the performance-structure relationship. This challenge stems from the fact that introducing mesopores usually alters the active sites or the chemical composition of the catalysts, adding further complexity to the investigation of porosity-induced performance in N-C materials. As a result, the interaction between porosity modifications and variations in active sites complicates understanding the performance-structure correlation in N-C materials. Evidently, maintaining consistency in the types of active sites and their immediate surroundings would facilitate a clearer understanding of the contribution of distinct pore types to the conversion of CO2 to CO. The aim of our study is to isolate the augmented porosity from other alterations in the catalysts' composition, allowing the impact of increased mesopore content in N-C materials to be studied on both the selectivity and activity of eCO2RR.
I present a strategy for enhancing the mesopore content in N-C materials derived from metal-organic frameworks (MOFs) by incorporating additional carbon sources to improve the catalytic performance of eCO2RR. Specifically, we used isoreticular MOF (i.e. IRMOF 3), with a pore size diameter of 1.5 nm, as the precursor for the carbon matrix. To prevent structural collapse and preserve porosity during the subsequent carbonization process, N-rich monomers containing O [furfuryl alcohol (FA)], known for its polycondensation properties, was introduced into the IRMOF-3 cavities through nanocasting as an additional carbon source, creating the FA-IRMOF-3 composite material. Therefore, after pyrolysis, we successfully designed two N-C catalyst materials featuring varying mesopore content with an average pore size of ~10 nm. The careful nanocasting process preserved the types and content of active sites and the size of catalysts, selectively enhancing the mesopore content in the resulting N-C catalyst (referred to as P-N-C). As a result, the P-N-C material continuously maintained a high FECO (>90%) and outperformed N-C and P-O-C across the entire potential window. Meanwhile, this substrate provides a large-surface-area substrate for the next SAC loading.