Self-Supporting Electrocatalyst Film Based on Self-Assembly of Heterogeneous Bottlebrush and Polyoxometalate for...

Developing efficient electrocatalysts to promote the hydrogen evolution reaction (HER) is essential for a green and sustainable future energy supply. For practical applications, it is a challenge to achieve the self-assembly of electrocatalyst from microscopic to macroscopic scales. Herein, a facile strategy is proposed to fabricate a self-supporting electrocatalyst film (CNT-g-PSSCo/PW₁₂ ) for HER by electrostatic interaction-induced self-assembly of cobalt polystyrene sulfonate-grafted carbon nanotube heterogeneous bottlebrush (CNT-g-PSSCo) and polyoxometalate (PW₁₂ ). Co²⁺ ions of CNT-g-PSSCo can function as junctions for interconnecting neighboring bottlebrushes to form the 3D nanonetwork structure and enable electrostatic capture of negatively charged PW₁₂ nanodots. Moreover, CNT backbones can provide highly conductive pathways to CNT-g-PSSCo/PW₁₂ . Such a self-assembled CNT-g-PSSCo/PW₁₂ displays a low overpotential of 31 mV at a current density of 10 mA cm^-2 and a small Tafel slope of 25 mV dec^-1 , showing high efficiency toward HER. Furthermore, CNT-g-PSSCo/PW₁₂ with a stable self-supporting film morphology exhibits long-term electrocatalytic stability over 1000 CV cycles without noticeable overpotential change in acidic media. The findings may provide a new avenue for constructing self-assembled functional nanonetwork materials with well-orchestrated structural hierarchy for many applications in energy, environment, catalysis, medicine, and others.