Lattice Distortion and H‐passivation in Pure Carbon Electrocatalysts for Efficient and Stable Two‐electron Oxygen Reduction to H₂O₂

Abstract

The exploration of inexpensive and efficient catalysts for oxygen reduction reaction (ORR) is crucial for chemical and energy industries. Carbon materials have been proved promising with different catalysts enabling 2 and 4e‐ ORR. Nevertheless, their ORR activity and selectivity is still complex and under debate in many cases. Many structures of these active carbon materials are also chemically unstable for practical implementations. Unlike the well‐discussed structures, this work presents a strategy to promote efficient and stable 2e‐ ORR of carbon materials through the synergistic effect of lattice distortion and H‐passivation (on the distorted structure). We show how these structures can be formed on carbon cloth, and how the reproducible chemical adsorption can be realized on these structures for efficient and stable H2O2 production. The work here gives not only new understandings on the 2e‐ ORR catalysis, but also the robust catalyst which can be directly used in industry.

Emerging Amorphized Metastable Structures to Break Limitations of 2D Materials for More Promising Electrocatalysis

“…The consumption of these active electronic states through the H-bonds accordingly improves the material’s stability. A similar example was also demonstrated on the highly distorted graphite lattice, where the dangling bond state was stabilized by H-passivation on distorted sites . Ever in this case, the H-passivated dangling sites and nearby atoms still exhibited much higher binding ability to O 2 compared to the pure and flat graphene lattice, which was highly stable and efficient in the 2e – ORR in the basic solution …”

“…A similar example was also demonstrated on the highly distorted graphite lattice, where the dangling bond state was stabilized by H-passivation on distorted sites . Ever in this case, the H-passivated dangling sites and nearby atoms still exhibited much higher binding ability to O 2 compared to the pure and flat graphene lattice, which was highly stable and efficient in the 2e – ORR in the basic solution Figure C shows another example, where the stabilization of metastable structure was reached by forming a surface hydration layer and hydrogen bond .…”

“…However, the potential passivation of these metastable sites with other chemicals (e.g., H + and OH – ) may need to be further considered. At least, the inner Helmholtz layer contains abundant H + , which possibly stabilizes the structure during the HER, similar to that observed on lattice distorted carbon material in the electrochemical oxygen reduction reaction (ORR) . Additionally, structural rearrangement should be accompanied by a reduction in surface activity, which is unfavorable for further binding with exotic atoms to enable more interesting catalytic reactions.…”

“…In EPR of metastable materials, the response signal depends on the density of dangling bond states. ,− , Figure F provides an example where the EPR response increases with the extent of S vacancy in metastable trigonal 1T’’’-MoS 2 . EPR was also utilized to verify the enhanced dangling bond state induced by lattice distortions . Regarding XPS, the dangling bond state can be characterized by shakeup satellite peaks .…”

“…EPR was also utilized to verify the enhanced dangling bond state induced by lattice distortions . Regarding XPS, the dangling bond state can be characterized by shakeup satellite peaks . It is important to note that stronger and higher binding energy shakeup satellite peaks indicate more unsaturated dangling states at higher energy levels, which are often incorrectly ascribed to chemically shifted peaks as a common error .…”