Rare Earth Single-Atom Catalysts for Nitrogen and Carbon Dioxide Reduction

Abstract

Single-atom catalysts (SACs) have attracted much attention owning to their high catalytic properties. Herein, yttrium and scandium rare earth SACs are successfully synthesized on a carbon support (Y1/NC and Sc1/NC). Different from the well-known M–N4 structure of M–N–C (M = Fe, Co) catalysts, Sc and Y atoms with a large atomic radius tend to be anchored to the large-sized carbon defects through six coordination bonds of nitrogen and carbon. Although Y- and Sc-based nanomaterials are generally inactive to room-temperature electrochemical reactions, Y1/NC and Sc1/NC SACs exhibit catalytic activities to nitrogen reduction reaction and carbon dioxide reduction reaction due to the modulation of the local electronic structure of Y/Sc single atoms by N and C coordination. The catalytic functions of rare earth single atoms not only demonstrate the magical effect of SACs but also promote the application of rare earth catalysts in room-temperature electrochemical reactions.

Sequential Synthesis and Active‐Site Coordination Principle of Precious Metal Single‐Atom Catalysts for Oxygen Reduction Reaction and PEM Fuel Cells

“…The simultaneous coordination method has been successfully used to prepare several SACs of Fe/Y/Sc‐N‐C. [ 16c,17 ] Using this method, PM chlorides and ZnO were simultaneously mixed with 2MI, sealed in a Teflon‐lined stainless autoclave under Ar protection, and finally heat‐treated at 220 °C for 18 h to obtain PM‐loaded ZIF (named as PM/ZIF‐simu). X‐ray diffraction (XRD) patterns of PM/ZIF‐simu (PM = Rh, Pd, Pt) are similar to that of pristine ZIF‐8, except that a small new peak appears at 2θ = 13.9° for Ir/ZIF‐simu (Figure 1b).…”

“…Scientists have developed strategies for doping (replacing Zn with foreign metal ions) and encapsulating (capturing foreign metal ions in the micropores) non‐precious transition metals (Fe, Co, Ni, etc.) [ 16 ] and rare earths (Y, Sc) [ 17 ] into ZIF‐8, which can be converted into carbon‐supported nitrogen‐coordinated SACs with 2–3 wt% metal after pyrolysis. However, the conventional doping strategy is not effective for PM probably because of the weak competitiveness or excessive ion size of PM compared to zinc.…”

Design Principles of Single Atoms on Carbons for Lithium–Sulfur Batteries

“…Liu et al found that rare earth yttrium (Y) and scandium (Sc) atoms with large atomic radius tend to coordinate with three nitrogen and three carbon atoms (Y/Sc‐N 3 C 3 ) at large‐scale carbon defects rather than the well‐known SA‐N 4 structure. [ 100 ]…”

Recent Advances in Phosphorus‐Coordinated Transition Metal Single‐Atom Catalysts for Oxygen Reduction Reaction

“…Density functional theory (DFT) calculations have been used to analyze the formation energy of the atomic active site and the adsorption energy of O 2 , ORR reaction intermediates on the active site, which can be used to judge the feasibility of active sites for ORR and analyze the reaction process at these sites [27–29] . The formation of phosphorus‐coordinated atomic metal M−P x embedded in graphene, such as Fe−P 4 and Co−P 4 , has been calculated energetically feasible [12] .…”