Single-Atom Iron Anchored on 2-D Graphene Carbon to Realize Bridge-Adsorption of O–O as Biomimetic Enzyme for Remarkably Sensitive Electrochemical Detection of H₂O₂

Abstract

Single-atom catalysis is mainly focused on its dispersed high-density catalytic sites, but delicate designs to realize a unique catalysis mechanism in terms of target reactions have been much less investigated. Herein an iron single atomic site catalyst anchored on 2-D N-doping graphene (Fe-SASC/G) was synthesized and further employed as a biomimetic sensor to electrochemically detect hydrogen peroxide, showing an extremely high sensitivity of 3214.28 μA mM–1 cm–2, which is much higher than that (6.5 μA mM–1 cm–2) of its dispersed on 1-D carbon nanowires (Fe-SASC/NW), ranking the best sensitivity among all reported Fe based catalyst at present. The sensor was also used to successfully in situ monitor H2O2 released from A549 living cells. The mechanism was further systematically investigated. Results interestingly indicate that the distance between adjacent single Fe atomic catalytic sites on 2-D graphene of Fe-SASC/G matches statistically well with the outer length of bioxygen of H2O2 to promote a bridge adsorption of −O–O– for simultaneous 2-electron transfer, while the single Fe atoms anchored on distant 1-D nanowires in Fe-SASC/NW only allow an end-adsorption of oxygen atoms for 1-electron transfer. These results demonstrate that Fe-SASC/G holds great promise as an advanced electrode material in selective and sensitive biomimetic sensor and other electrocatalytic applications, while offering scientific insights in deeper single atomic catalysis mechanisms, especially the effects of substrate dimensions on the mechanism.

Stretchable Oxygen-Tolerant Sensor Based on a Single-Atom Fe–N4 Electrocatalyst for Observing the Role of Oxidative Stress in Hypertension

“…Zhu et al designed an Fe 3 C@C/Fe–N–C material with single atomic sites that exhibits excellent POD-like activity and electrochemical H 2 O 2 sensing ability with a high sensitivity and low detection limit, which can sensitively monitor the H 2 O 2 released from living cells . Li et al reported a biomimetic sensor based on iron single-atom materials to electrochemically monitor H 2 O 2 , which is currently ranked as the best Fe-based catalyst in terms of sensitivity and successful in situ monitoring of the H 2 O 2 released from A549 living cells . Although single-atom nanomaterials for H 2 O 2 monitoring have been constructed, to the best of our knowledge, a flexible and stretchable H 2 O 2 sensor based on single-atom materials has not yet been explored, restricting the application in monitoring ROS in cellular mechanotransduction.…”

“…32 Li et al reported a biomimetic sensor based on iron single-atom materials to electrochemically monitor H 2 O 2 , which is currently ranked as the best Fe-based catalyst in terms of sensitivity and successful in situ monitoring of the H 2 O 2 released from A549 living cells. 33 Although single-atom nanomaterials for H 2 O 2 monitoring have been constructed, to the best of our knowledge, a flexible and stretchable H 2 O 2 sensor based on single-atom materials has not yet been explored, restricting the application in monitoring ROS in cellular mechanotransduction. In addition, the design and fabrication of high-performance electrocatalysts where the H 2 O 2 reduction reaction (HPRR) occurs before the oxygen reduction reaction (ORR) are essential because hypoxia usually leads to oxidative stress and the production of ROS.…”

Single-atom catalysts: promotors of highly sensitive and selective sensors

“…16a and b). 167 DFT calculation exhibits that the distances between neighbouring sites match the optimum “bridge-adsorption” mode for the catalysis.…”

Fe Single-Atom Nanozymes for Real-Time Dual Monitoring of H2O2 Released from Living Cells

“…Li et al prepared FeSAs (NH 2 -UIO-66 NPs) by coordinating Zr66 clusters with 2-amino-terephthalic acid and developed a H 2 O 2 sensor with a low detection limit. Li et al synthesized FeSAs anchored to two-dimensional nitrogen-doped graphene to detect H 2 O 2 secretion from A549 cells. Therefore, by changing the synthesis mechanism of FeSAs, it is expected to develop H 2 O 2 detection sensors with broad application prospects.…”