Bridging oxidase catalysis and oxygen reduction electrocatalysis by model single-atom catalysts

Abstract

Nanocatalysts with enzyme-like catalytic activities, such as oxidase mimics, are extensively used in biomedicine and environmental treatment. Searching for enzyme-like nanomaterials, clarifying the origins of the catalytic activity and developing activity assessment methodologies are therefore of great significance. Here, we report that oxidase catalysis and oxygen reduction reaction (ORR) electrocatalysis can be well bridged based on their identical activity origins, which makes facile electrocatalytic ORR activity measurements intrinsically applicable to oxidase-like activity evaluations. Inspired by natural heme-copper oxidases, Cu/Fe-doped single-atom catalysts (SACs) were first synthesized and used as model catalysts. Chromogenic reactions, electrochemical voltammetric measurements and density functional theory calculations further verify the linear relationship between the oxidase-like and ORR catalytic activities of the catalysts; thus, an effective descriptor ($| {\overline {{j_{\rm{n}}}} } |$) is proposed for rapid enzymatic catalyst evaluation. The enhanced tumour therapeutic efficacy of SACs has been evidenced to result from their oxidase-like/ORR activities, which proves that numerous ORR electrocatalysts are promising candidates for oxidase mimics and tumour therapy. The synergistic catalytic effect of the biomimetic heterobinuclear Cu-Fe centres has also been thoroughly probed.

Copper‐Single‐Atom Coordinated Nanotherapeutics for Enhanced Sonothermal‐Parallel Catalytic Synergistic Cancer Therapy

“…The rates of the chromogenic reaction indicate the biocatalytic activity order of HA‐NC_Cu+H 2 O 2 +GSH+Ultrasound > HA‐NC_Cu+H 2 O 2 +GSH > HA‐NC_Cu+H 2 O 2 +Ultrasound > HA‐NC_Cu+H 2 O 2 ≫ HA‐NC+H 2 O 2 +GSH+Ultrasound ≈ H 2 O 2 ≈ Ultrasound, indicating that the active metal atom is an important factor for catalytic activity. [ 24 ] The biocatalytic performance of HA‐NC_Cu with ultrasound irradiation was 2.02‐fold higher compared to that of the group with no irradiation. The production of •OH gradually increased with an increase in the concentration of H 2 O 2 , which is consistent with typical Michaelis–Menten kinetics.…”

“…that the active metal atom is an important factor for catalytic activity. [24] The biocatalytic performance of HA-NC_Cu with ultrasound irradiation was 2.02-fold higher compared to that of the group with no irradiation. The production of •OH gradually increased with an increase in the concentration of H 2 O 2 , which is consistent with typical Michaelis-Menten kinetics.…”

Molecular insights of nanozymes from design to catalytic mechanism

“…In another outstanding contribution, oxidase catalysis was successfully bridged with ORR electrocatalysis. Using Cu/ Fe-doped single-atom as model catalysts (Figure 10d), Shi's group [100] created CF-HNCS with outstanding OXD-like activity (Figure 10e). Notably, by using steady-state linear sweep voltammetry (LSV), the order of ORR activity shows great accordance with their OXD-like activity identified by TMB.…”

The iron-manganese bimetal-MOF with double mimic enzyme: DFT verification and colorimetric detection of Cr(vi)

“…4(C), the path of oxidase-like catalysis for the reduction of O 2 to H 2 O was generally considered similar to that of the oxygen reduction reaction (ORR). 54 Subsequently, the corresponding free energy changes in the oxygen intermediates were calculated to study the limiting reaction barrier (Fig. 4D).…”