Electrochemically in situ controllable assembly of hierarchically-ordered and integrated inorganic–carbon hybrids for efficient hydrogen evolution. Issue 6 (20th September 2018)

• Record Type: Journal Article
• Authors: Wang, Zhong-Li; Sun, Keju; Henzie, Joel; Hao, Xianfeng; Ide, Yusuke; Takei, Toshiaki; Bando, Yoshio; Yamauchi, Yusuke
• Is Part Of: Materials horizons. Volume 5:Issue 6(2018)
• Page Start: 1194
• Page End: 1203
• Publication Date: 2018-09-20
• Subjects: Materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8mh00773j
• Languages: English
• ISSNs: 2051-6347

Abstract

Abstract : A novel redox-unit cooperative assembly strategy is developed to construct hierarchically-ordered and integrated inorganic–carbon hybrids by electrochemically tuning the PANI to controllably bond metal complexes. Abstract : Inorganic–carbon hybrid materials are an emerging class of nanostructured catalysts that can enhance various energy-oriented electrochemical reactions. Despite recent progress, it is still very challenging to controllably generate the hybrid carbon architecture and its inorganic components with a single approach. Inspired by the flexible redox properties of conductive polyaniline (PANI) polymer, we develop a redox-unit cooperative assembly strategy to synthesize hierarchically-ordered and integrated inorganic–carbon hybrids by electrochemically constructing the nanostructures of PANI and then modifying their redox states to controllably bond different metal complexes. The needle-branched PANI nanofibers are assembled in situ into a three-dimensional (3D) hierarchical framework on carbon paper by an anion induced electrochemical polymerization. Interestingly, tuning the redox states of PANI with a potentiostatic method achieves a controllable metal complex loading. The theoretical calculations show that the oxidized units can strongly bond metal complexes while reduced units don't react significantly due to a high formation energy. Both units with proper proportions can cooperatively control the concentration and spatial distribution of metal complexes in the PANI framework. After thermal treatment, the metal/PANI composites are transformed into a series of inorganic–carbon hybrids including metals and metal oxides, carbides, and sulfides. This novel strategy not only significantly improves the catalytic performance of non-noble metal hybrid materials but also greatly increases the utilization efficiency of noble metal catalysts in the hydrogen evolution reaction. Surprisingly, the optimized Pt@NC catalyst exhibits an ultrahigh mass activity that is ∼5.3-times better than the commercial Pt/C catalyst.