Metal–organic framework-derived single atom catalysts for electrocatalytic reduction of carbon dioxide to C1 products

Abstract

Electrochemical carbon dioxide reduction reaction (eCO2 RR) is an efficient strategy to relieve global environmental and energy issues by converting excess CO2 from the atmosphere to value-added products. Single-atom catalysts...

Electronic Structure Design of Transition Metal-Based Catalysts for Electrochemical Carbon Dioxide Reduction

“…The strategic incorporation of transition metal atoms into carbon-based substrates constitutes a pivotal approach in nanomaterial design. ,− Leveraging the excellent conductivity and stability of carbon substrates, this method establishes a robust platform, allowing for intricate fine-tuning through the modulation of metal type and concentration. , It is worth noting that incorporating transition metal atoms as active sites with the inactive carbon substrate markedly improves the atomic utilization rate compared with bulk materials. , Moreover, carbon substrate can provide further adjustment space of active sites, such as secondary atom doping. , Built upon carbon substrates, single-atom catalysts (SACs), featuring individual metal atoms affixed to the support surface, have attracted tremendous research interests owing to their intriguing catalytic performance compared to conventional nanoparticle catalysts, including high atom efficiency, high utilization of metal valence electrons, excellent thermal stability, and flexible tunability. ,− It is worth mentioning that since their inception, SACs have not only been limited to a single atom anchored to a substrate, but evolving to a more intricate structure with multiple nonmetallic atoms cooperating (e.g., M–N–C catalysts, M = metal atom) − or multiple transition metal atoms (e.g., dual atom catalysts (DACs). − CO 2 RR over SACs traces its origins to 1970s, where cobalt and nickel phthalocyanines (Pc) were used for this process . It had declared that compared with Mn-Pc and Fe-Pc, the d z orbitals of Co-Pc and Ni-Pc in their dinegative states were occupied and ligand π electrons were excessive, where a foundation was laid for the later further tuning and optimization of the electronic structure of monatomic transition metals .…”

Progress and Perspective of Single-atom Catalysts for the Electrochemical CO2 Reduction Reaction for Fuels and Chemicals

“…Mechanical stability refers to the physical robustness and structural integrity of a material or catalyst under operational conditions. During the catalytic reaction, factors such as the elevated atom utilization rate, the augmentation of surface free energy, and the presence of a highly unsaturated coordination setting can enhance the mobility of individual atoms on the support surface [3]. As a result, individual atoms have the tendency to cluster together, in a process called sintering.…”

“…Conversely, Ni and Zn have a weaker bond with CO, making CO2 more likely to be reduced to CO. Meanwhile, Sn and Bi, which also bind weakly to CO, primarily produce formate [3]. C2 products on the other hand is more challenging than C1 products due to the need for C-C coupling, a kinetically and mechanically difficult step.…”

“…Although many efforts have been made to optimize the CO2RR process, the efficacy of conversion of CO2 remains subpar, characterized by suboptimal activity and poor product selectivity. Compromised activity sites due to bulky catalysts hinder the efficiency of conversion [3]. Therefore, seeking out versatile catalyst that could ensure stability and selectivity is crucial not only for the promotion of clean energy sources, but also for the development of a sustainable alternative energy source.…”