PANI-modified Pt/Na4Ge9O20 with low Pt loadings: Efficient bifunctional electrocatalyst for oxygen reduction and hydrogen evolution

Min Wang ^a,b, Luhua Jiang ^a,**, Qinru Li ^b, Xiaoxia Zhou ^b,*

a College of Materials Science & Engineering, Qingdao University of Science & Technology, 53 Zhengzhou Road, Qingdao, 266042, PR China

b State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai, 200050, PR China

Abstract

Exploring cost-effective electrocatalysts for the oxygen reduction reaction (ORR) and
hydrogen evolution reaction (HER) have been a goal in the sustainable hydrogen-based society. Although abundant of alternative materials have been developed, Pt/C remains the most efficient electrocatalyst for the ORR and HER. Nevertheless, improving the stability and reducing Pt loading for Pt-based electrocatalysts are still big challenges. Herein, semiconductor crystals Na4Ge9O20 with richer topology structure was chosen as electrocatalyst support, subsequently, the conductive polymer polyaniline (PANI) was decorated on semiconductor Na4Ge9O20, low-content Pt nanoparticles (Pt NPs) with the size of 1-3 nm were then uniformly anchored on the surface of Na4Ge9O20-PANI to obtain the efficient bifunctional electrocatalyst for ORR and HER in the acidic solution. More importantly, the stability and mass activity of the obtained electrocatalyst 5 wt% Pt/Na4Ge9O20-PNAI are significantly higher than that of commercial 20 wt% Pt/C for ORR and HER. It was proposed that the PANI could not only promote the electron transfer from Na4Ge9O20 to Pt, but also stabilize the Pt NPs, thus, improving the electrocatalytic activity and stability of 5 wt% Pt/Na4Ge9O20-PNAI.