Electronic-reconstruction-enhanced hydrogen evolution catalysis in oxide polymorphs

Yangyang Li ,Xiao Renshaw Wang ,Andrew T S Wee ,Chi Sin Tang ,T Venkatesan ,Yong‐Wei Zhang ,Xinmao Yin ,Jianwei Chai ,Shuai Dong ,Zhi Gen Yu ,Shijie Wang ,Kun Han ,Xiaojiang Yu ,John Wang ,Dongyang Wan ,Ling Wang ,Haijun Wu ,Stephen J Pennycook ,Yakui Weng ,Mark B H Breese ,Lai Mun Wong ,Jun Min Xue ,Jingsheng Chen

doi:10.1038/s41467-019-11124-w

Abstract

Transition metal oxides exhibit strong structure-property correlations, which has been extensively investigated and utilized for achieving efficient oxygen electrocatalysts. However, high-performance oxide-based electrocatalysts for hydrogen evolution are quite limited, and the mechanism still remains elusive. Here we demonstrate the strong correlations between the electronic structure and hydrogen electrocatalytic activity within a single oxide system Ti2O3. Taking advantage of the epitaxial stabilization, the polymorphism of Ti2O3 is extended by stabilizing bulk-absent polymorphs in the film-form. Electronic reconstructions are realized in the bulk-absent Ti2O3 polymorphs, which are further correlated to their electrocatalytic activity. We identify that smaller charge-transfer energy leads to a substantial enhancement in the electrocatalytic efficiency with stronger hybridization of Ti 3d and O 2p orbitals. Our study highlights the importance of the electronic structures on the hydrogen evolution activity of oxide electrocatalysts, and also provides a strategy to achieve efficient oxide-based hydrogen electrocatalysts by epitaxial stabilization of bulk-absent polymorphs.

Highlights

Transition metal oxides exhibit strong structure-property correlations, which has been extensively investigated and utilized for achieving efficient oxygen electrocatalysts
We demonstrate the close correlation between the electronic structures and HER catalytic activities in a single-oxide system (Ti2O3) with strongly correlated electrons
Three Ti2O3 polymorphs were successfully fabricated in the epitaxial film form by using the pulsed laser deposition (PLD) technique (Fig. 1a)

Summary

Introduction

Transition metal oxides exhibit strong structure-property correlations, which has been extensively investigated and utilized for achieving efficient oxygen electrocatalysts. Our study highlights the importance of the electronic structures on the hydrogen evolution activity of oxide electrocatalysts, and provides a strategy to achieve efficient oxide-based hydrogen electrocatalysts by epitaxial stabilization of bulk-absent polymorphs. Smaller charge-transfer energy leads to the stronger hybridization strength of the Ti 3d –O 2p orbitals, which lower the d-band center of Ti and weakens the H adsorption, further resulting in the enhanced HER activity in those epitaxially stabilized polymorphs. This electronic-reconstruction enhanced HER activity, achieved in the structure-tailored Ti2O3, introduces a previously unrecognized route to explore more efficient TMObased HER electrocatalysts by enhancing the metal–oxygen hybridization via selective stabilization of polymorph phases

Methods

Results

Conclusion