Single-Atom Catalysts Based on the Metal–Oxide Interaction

Abstract

Metal atoms dispersed on the oxide supports constitute a large category of single-atom catalysts. In this review, oxide supported single-atom catalysts are discussed about their synthetic procedures, characterizations, and reaction mechanism in thermocatalysis, such as water–gas shift reaction, selective oxidation/hydrogenation, and coupling reactions. Some typical oxide materials, including ferric oxide, cerium oxide, titanium dioxide, aluminum oxide, and so on, are intentionally mentioned for the unique roles as supports in anchoring metal atoms and taking part in the catalytic reactions. The interactions between metal atoms and oxide supports are summarized to give a picture on how to stabilize the atomic metal centers, and rationally tune the geometric structures and electronic states of single atoms. Furthermore, several directions in fabricating single-atom catalysts with improved performance are proposed on the basis of state-of-the-art understanding in metal-oxide interactions.

High Performance of Single‐atom Catalyst Pd1/MgO for Semi‐hydrogenation of Acetylene to Ethylene in Excess Ethylene

“…The turnover frequency (TOF) of Pd 1 /MgO−H100 SAC is 0.074 s −1 , exceeding the recently reported Pd 1 /ND@G, one of the best Pd SACs for this reaction [20] . The stability of oxide supported SACs in reduction atmosphere at elevated temperatures is a great concern [17] . Considering the good stability of our Pd 1 /MgO and the strong interaction between Pd atoms and MgO support, we further reduced the sample at 250 °C (denoted as Pd 1 /MgO−H250), a temperature that is high enough to arouse aggregation of many single metal atoms [21] .…”

“…Supported Pd SACs have already been successfully applied to acetylene semi‐hydrogenation and show promising catalytic performance [1] . However, the fabrication of stable supported Pd SACs, especially with relatively high metal loading, still remains a formidable challenge [17] . In this work, we report the fabrication of MgO supported Pd SAC via ball milling which has good thermostability even at 600 °C calcination and up to 250 °C reduction.…”

Recent Advances of CeO2‐Based Electrocatalysts for Oxygen and Hydrogen Evolution as well as Nitrogen Reduction

“…The single metal atoms stabilized by CeO 2 support with high dispersion degree endow the corresponding SACs with great prospective in CO oxidation, CH 4 oxidation, water-gas shift reaction and etc. [158] Qi et al systematically investigated 28 single transition metal atoms anchored on stepped CeO 2 (CeO 2 À S) by DFT calculation to screen potential electrocatalysts for NRR. [159] They first proved that 26 SACs were stable by calculating the binding energy.…”

“…Single‐atom catalysts (SACs) have attracted more and more attention in electrocatalytic field. The single metal atoms stabilized by CeO 2 support with high dispersion degree endow the corresponding SACs with great prospective in CO oxidation, CH 4 oxidation, water‐gas shift reaction and etc [158] . Qi et al.…”

Synergizing strong metal-support interactions and spatial confinement boosts dynamics of atomic nickel for hydrogenations

“…micropores) 15 are two widely adopted methodologies to achieve for higher stability. However, too strong MSI might over stabilize the active sites, hindering its activation to reactants/intermediates 14,16 ; con nement of the metal species in micropores might also limit mass transfers 15,17 . Consequently, a seesaw relation between stability and activity have been often observed, obscuring the tremendous efforts for optimizing the catalytic performance of SADCs [18][19][20] .…”