Polypyrrole Hollow Microspheres with Boosted Hydrophilic Properties for Enhanced Hydrogen Evolution Water Dissociation Kinetics

Haihong Zheng; Fang Yang; Tuzhi Xiong; David Adekoya; Yongchao Huang; M-Sadeeq Jie Tang Balogun

doi:10.1021/acsami.0c16938

Polypyrrole Hollow Microspheres with Boosted Hydrophilic Properties for Enhanced Hydrogen Evolution Water Dissociation Kinetics

ACS Appl Mater Interfaces. 2020 Dec 23;12(51):57093-57101. doi: 10.1021/acsami.0c16938. Epub 2020 Dec 9.

Authors

Haihong Zheng¹, Fang Yang², Tuzhi Xiong², David Adekoya³, Yongchao Huang⁴, M-Sadeeq Jie Tang Balogun²

Affiliations

¹ Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, P. R. China.
² College of Materials Science and Engineering, Hunan University, Changsha 410082, China.
³ Australian Institute of Bioengineering & Nanotechnology, The University of Queensland, Brisbane, Queensland 4222, Australia.
⁴ Institute of Environmental Research at Greater Bay, Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, Guangzhou University, Guangzhou 510006, China.

PMID: 33296164
DOI: 10.1021/acsami.0c16938

Abstract

The water dissociation step (H₂O + M + e^- → M - H_ads + OH^-) is a crucial one toward achieving high-performance hydrogen evolution reaction (HER). The application of electronic conducting polymers (ECPs), such as polypyrrole (PPy), as the electrocatalyst for HER is rarely reported because of their poor adsorption energy per water molecule, which hinders the Volmer step. Herein, we strongly enrich PPy hollow microspheres (PPy-HMS) with attractive HER activity by enhancing their hydrophilic properties through hybridization with good water affinity SiO₂. The as-prepared PPy-coated SiO₂ (PPy@SiO₂-HMS) achieves a current density of 10 mA cm^-2 at -123 mV, which is lower than that of pristine PPy-HMS (-192 mV). Raman and X-ray photospectroscopy analyses reveal that the enhanced HER catalytic capability can be attributed to the strong electronic couplings between PPy and SiO₂, and this improves the adsorption energy per water molecule and in turn accelerates the water dissociation kinetics on PPy. This work highlights the potential application of low-cost ECPs as promising electrocatalysts for water electrolysis.

Keywords: alkaline HER; conducting polymer; hollow core−shell; polypyrrole; water dissociation.