Record volumetric activities of oxygen electroreduction in partly packing graphene/AgTCNQ electrodes
Chen Zhang,
Wenqiang Wu,
Qi Huang,
Lili Jiang,
Ming Li,
Jingjing Duan,
Jun Lin,
Sheng Chen
Affiliations
Chen Zhang
Key Laboratory for Soft Chemistry and Functional Materials (Ministry of Education), School of Chemistry and Chemical Engineering School of Energy and Power Engineering, Nanjing University of Science and Technology Nanjing, 210094, China
Wenqiang Wu
Key Laboratory for Soft Chemistry and Functional Materials (Ministry of Education), School of Chemistry and Chemical Engineering School of Energy and Power Engineering, Nanjing University of Science and Technology Nanjing, 210094, China
Qi Huang
Key Laboratory for Soft Chemistry and Functional Materials (Ministry of Education), School of Chemistry and Chemical Engineering School of Energy and Power Engineering, Nanjing University of Science and Technology Nanjing, 210094, China
Lili Jiang
Key Laboratory for Soft Chemistry and Functional Materials (Ministry of Education), School of Chemistry and Chemical Engineering School of Energy and Power Engineering, Nanjing University of Science and Technology Nanjing, 210094, China
Ming Li
Key Laboratory for Soft Chemistry and Functional Materials (Ministry of Education), School of Chemistry and Chemical Engineering School of Energy and Power Engineering, Nanjing University of Science and Technology Nanjing, 210094, China
Jingjing Duan
Key Laboratory for Soft Chemistry and Functional Materials (Ministry of Education), School of Chemistry and Chemical Engineering School of Energy and Power Engineering, Nanjing University of Science and Technology Nanjing, 210094, China; Corresponding authors.
Jun Lin
School of Electronic Science and Engineering, Nanjing University, Nanjing 210008, China; Corresponding authors.
Sheng Chen
Key Laboratory for Soft Chemistry and Functional Materials (Ministry of Education), School of Chemistry and Chemical Engineering School of Energy and Power Engineering, Nanjing University of Science and Technology Nanjing, 210094, China; Corresponding authors.
Volumetric activity is the key to success in many space-constrained electrochemical devices. However, the state-of-the-art volumetric activities for oxygen electroreduction to hydrogen peroxide only achieve up to 30.8 mg cm−3 h−1. This is attributable to the traditional catalyst electrodes for oxygen electroreduction made of substrate-based configuration. Here we show that a variety of self-suspended materials can be used as self-suspended catalyst electrodes without the need for any substrates. By using graphene-AgTCNQ hybrid hydrogels as a proof-to-concept example, we have demonstrated the partly packing of the graphene-based electrode (packing densities from 0.2 to 0.83 g cm−3) realizing recorded H2O2 volumetric rate of 37910 mg cm−3 h−1 (Faradic efficiency: 90.4%), which are three orders of magnitude of the literature. Further mechanism study highlights the important role of the self-suspended configuration of electrodes that can be manipulated into compact yet porous architectures without compromising electrochemically active surface areas (ECSAs). Moreover, density functional theory (DFT) calculations reveal a two-electron-transfer oxygen electroreduction pathway occurring on silver active sites via the rate-determining step of *OOH + H+ + e− → H2O2.
