Investigation of strain effect on hydrogen evolution reaction catalysts of TiC2
Strain engineering is an effective strategy to tune the electronic,magnetic and optical properties of a-tomically thin materials.Using first-principles calculations,we show that strain is also effective for tuning the catalytic activity of TiC2 towards the hydrogen evolution reaction(HER),which is essential for electrochemical hydrogen from water splitting.We only consider the range from 0 to 8％.It is found that biaxial tensile strain can enhance the HER activity more effectively than uniaxial stretching at 25％hydrogen coverage.However,the TiC2 sheet has the highest maximum hydrogen coverage by the stretching in the b direction,and the tensile strain in the b direction greatly improves the catalytic performance of TiC2 monolayers with different hydrogen covera-ges.Electronic structure calculations show that tensile strain can activate the relatively inert inner valence elec-trons,which leads to the instability of the system and the improvement of catalytic activity.The insights obtained in the present work may prove to be instrumental in improving the catalytic activity of two-dimensional materials using strain as an effective means and in exploring new approaches for more effectively tuning their electronic structure and catalytic activities.
Density functional theoryTiC2 monolayer sheetCoverage rateStrain
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