Recent Progress on Electrode Design for Efficient Electrochemical Valorisation of CO₂, O₂, and N₂

Abstract

CO2 reduction, two‐electron O2 reduction, and N2 reduction are sustainable technologies to valorise common molecules. Their further development requires working electrode design to promote the multistep electrochemical processes from gas reactants to value‐added products at the device level. This review proposes critical features of a desirable electrode based on the fundamental electrochemical processes and the development of scalable devices. A detailed discussion is made to approach such a desirable electrode, addressing the recent progress on critical electrode components, assembly strategies, and reaction interface engineering. Further, we highlight the electrode design tailored to reaction properties (e.g., its thermodynamics and kinetics) for performance optimisation. Finally, the opportunities and remaining challenges are presented, providing a framework for rational electrode design to push these gas reduction reactions towards an improved technology readiness level (TRL).

NH3 Electrosynthesis from N2 Molecules: Progresses, Challenges, and Future Perspectives

“…These two scientific problems lead to the low Faradaic efficiency (FE, <60%), NH 3 yield rate (∼10 −9 mol s −1 cm −2 ), and current density (<1 mA cm −2 ) of NRR process, finally inhibiting the optimization and development of the whole NRR system. 30 To alleviate these challenges, the possible strategies covering the whole electrochemical system such as the design of catalysts, electrodes, electrolytes, electrolyzers, etc. will be discussed in this section.…”

“…Meanwhile, the NRR process is also disturbed by the competitive HER, due to the close thermodynamic potentials between NRR (0.093 V) and HER (0 V) as well as the faster kinetic rate of HER (2e – -transfer process) than NRR (6e – -transfer process). These two scientific problems lead to the low Faradaic efficiency (FE, <60%), NH 3 yield rate (∼10 –9 mol s –1 cm –2 ), and current density (<1 mA cm –2 ) of NRR process, finally inhibiting the optimization and development of the whole NRR system . To alleviate these challenges, the possible strategies covering the whole electrochemical system such as the design of catalysts, electrodes, electrolytes, electrolyzers, etc.…”

Graphene and MOF Assembly: Enhanced Fabrication and Functional Derivative via MOF Amorphization

“…[13] Lastly, the large surface area provided by VG ensures enhanced exposure of the active sites to reactants, leading to improved electrocatalytic performances. [15,16] In this study, we specifically focus on zeolitic imidazolate frameworks (ZIFs), a well-studied subset of MOFs that can be readily tailored for electrocatalysis. [4,17] The fabrication only involves a one-step impregnation of VG into a ZIF precursor, which successfully assembles a series of ZIFs, including ZIF-7, ZIF-8, and ZIF-67.…”