Unravelling the Effect of Activators used in The Synthesis of Biomass‐Derived Carbon Electrocatalysts on the Electrocatalytic Performance for CO₂ Reduction

Abstract

N‐doped carbon materials can be efficient and cost‐effective catalysts for the electrochemical CO2 reduction reaction (CO2RR). Activators are often used in the synthesis process to increase the specific surface area and porosity of these carbon materials. However, owing to the diversity of activators and the differences in physicochemical properties that these activators induce, the influence of activators used for the synthesis of N‐doped carbon catalysts on their electrochemical performance is unclear. In this study, a series of bagasse‐derived N‐doped carbon catalysts is prepared with the assistance of different activators to understand the correlation between activators, physicochemical properties, and electrocatalytic performance for the CO2RR. The properties of N‐doped carbon catalysts, such as N‐doping content, microstructure, and degree of graphitization, are found to be highly dependent on the type of activator applied in the synthesis procedure. Moreover, the overall CO2RR performance of the synthesized electrocatalysts is not determined only by the N‐doping level and the configuration of the N‐dopant, but rather by the overall surface chemistry, where the porosity and the degree of graphitization are jointly responsible for significant differences in CO2RR performance.

Biomass‐Derived Electrocatalysts: Low‐Cost, Robust Materials for Sustainable Electrochemical Energy Conversion

“…[17,46,47,51,55,56] Using low-cost, renewable biomass as raw materials, which include proteins (such as hemoglobin, collagen, and so on) and polysaccharides (such as chitin, cellulose, and so on), to synthesize carbon materials for use in electrocatalysis has great potential and advantages. [17,47,48,50,51,[55][56][57] High-temperature pyrolysis of biomass materials has been used to produce carbon materials. [17,47,48,50,51,[55][56][57] These biomass-derived carbon materials preserve the characteristic hierarchical structures and porous nature of the original materials.…”

“…[17,47,48,50,51,[55][56][57] High-temperature pyrolysis of biomass materials has been used to produce carbon materials. [17,47,48,50,51,[55][56][57] These biomass-derived carbon materials preserve the characteristic hierarchical structures and porous nature of the original materials. [47,48,50,51,56,57] The porous morphologies of these carbon carriers facilitate mass transport, and their high specific surface areas provide abundant space for active sites.…”

“…[17,47,48,50,51,[55][56][57] These biomass-derived carbon materials preserve the characteristic hierarchical structures and porous nature of the original materials. [47,48,50,51,56,57] The porous morphologies of these carbon carriers facilitate mass transport, and their high specific surface areas provide abundant space for active sites. [17,47,48,50,51,[55][56][57] Biomass often contains large amounts of proteins, amino acids (AAs), and other substances, leading to the generation of self-doped C during biomass pyrolysis, including N, P, S, and so on.…”

Tuning the Properties of N-Doped Biochar for Selective CO2 Electroreduction to CO

“…Furthermore, Hursán et al prepared N-doped carbon catalysts with different pore sizes via a sacrificial support method and found that the catalysts showed different selectivity, activity, and stability even with similar N-doping content and a similar distribution of N-containing species and no correlation was found between the specific surface area and catalytic performance. In previous work, we also found that there is no significant correlation between the catalytic performance and specific surface area, and N-doping content and that the ratio of mesopores and the degree of graphitization play an essential role . We believe that an over-emphasis on the effects of specific surface area and N-doping level can easily lead to lopsided conclusions, which do not fully reflect the actual structure–performance relationships of N-doped carbon catalysts.…”

“…In previous work, we also found that there is no significant correlation between the catalytic performance and specific surface area, and N-doping content and that the ratio of mesopores and the degree of graphitization play an essential role. 30 We believe that an over-emphasis on the effects of specific surface area and N-doping level can easily lead to lopsided conclusions, which do not fully reflect the actual structure−performance relationships of N-doped carbon catalysts. Therefore, to develop better N-doped carbon catalysts for the CO 2 RR, it is necessary to further elucidate the structure−performance relationship of Ndoped carbon materials through a comprehensive and integrated analysis.…”