J. Mater. Chem. A｜Ir atom bridged N/S co-doped MXene to accelerate hydrogen evolution

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Research abstract

Two-dimensional Ti3C2Tx MXenes have great potential as low-cost single-atom supported structural substrates due to their unique physicochemical properties. However, the systematic exploration of the interactions between MXenes and single atoms is still in its infancy. In view of this, the research team of Taiwan Synchrotron Radiation Research Center Chan Ting-Shan, Hunan University Professor Luo Min, Tan Yongwen published the latest research results in "J. Mater. Chem. A", constructing a porous heteroatom (N, S) Ir single-atom catalyst supported on co-doped Ti3C2Tx. According to the analysis of XAS results, it was found that a new bridge structure was formed in situ between Ir atoms and N and S atoms, which made Ir atoms have good dispersion on N, S doped Ti3C2Tx. The optimized IrSA-2NS-Ti3C2Tx catalyst exhibits excellent HER activity in both acidic and basic environments. DFT calculation results show that N/S co-doped Ti3C2Tx can capture electrons from Ir single atoms, which leads to charge redistribution at the interface of Ti3C2Tx and further improves HER activity. This work provides a new idea for improving the regulation of the bridging state of active sites distributed at the atomic level in electrocatalysis.

Graphical guide



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Figure 1. Synthesis process and microstructure characterization of IrSA-2NS-Ti3C2Tx catalyst.




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Figure 2. Chemical states and coordination environments of Ir single atoms.



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Figure 3. Electrocatalytic HER performance of different Ir-NS-Ti3C2Tx catalysts.



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Figure 4. DFT theoretical calculations.



Summarize

This paper demonstrates the electronic metal support interaction (EMSI) between porous N/S co-doped Ti3C2Tx supports and Ir single atoms, and the strength of this interaction can be regulated by the N-S ratio. Combined with XAS and HAADF-STEM analysis, the bridge structure formed in situ between Ir atoms and nitrogen or sulfur atoms was proved. Theoretical calculations show that N/S co-doped Ti3C2Tx can capture electrons in Ir atoms through the interaction of highly coordinated Ir-N with Ir-S, further realizing electron redistribution at the interface. The aforementioned EMSI interactions can induce rehybridization and charge transport at the interface, which is achieved through the formation of new chemical bonds and rearrangement of molecular energy levels.



Literature link

https://doi.org/10.1039/D2TA00550F

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