In Situ “Chainmail Catalyst” Assembly in Low‐Tortuosity, Hierarchical Carbon Frameworks for Efficient and Stable Hydrogen Generation

• Published in: Advanced energy materials 2018-09, Vol.8 (25), p.n/a
• Main Authors: Li, Yiju, Gao, Tingting, Yao, Yonggang, Liu, Zhenyu, Kuang, Yudi, Chen, Chaoji, Song, Jianwei, Xu, Shaomao, Hitz, Emily M., Liu, Boyang, Jacob, Rohit J., Zachariah, Michael R., Wang, Guofeng, Hu, Liangbing
• Format: Article
• Language: English
• Subjects: Assembly; Carbon; Carbon nanotubes; Catalysis; Catalysts; chainmail catalysts; Chains; Chemical vapor deposition; Dispersion; Electrocatalysts; Encapsulation; Energy conversion efficiency; Energy storage; Heat shock; Heat treatment; Hydrogen; Hydrogen evolution; hydrogen evolution reaction; Hydrogen production; Hydrogen storage; in situ self‐assembly; Intermetallic compounds; Iron compounds; low tortuosity; Mass transfer; Nanoparticles; Nickel base alloys; Nickel compounds; Nitrogen; Organic chemistry; Slurries; Transition metals
• ISSN: 1614-6832; 1614-6840
• DOI: 10.1002/aenm.201801289

The chainmail catalysts (transition metals or metal alloys encapsulated in carbon) are regarded as stable and efficient electrocatalysts for hydrogen generation. However, the fabrication of chainmail catalysts usually involves complex chemical vapor deposition (CVD) or prolonged calcination in a furnace, and the slurry‐based electrode assembly of the chainmail catalysts often suffers from inferior mass transfer and an underutilized active surface. In this work, a freestanding wood‐based open carbon framework is designed embedded with nitrogen (N) doped, few‐graphene‐layer‐encapsulated nickel iron (NiFe) alloy nanoparticles (N‐C‐NiFe). 3D wood‐derived carbon framework with numerous open and low‐tortuosity lumens, which are decorated with carbon nanotubes (CNTs) “villi”, can facilitate electrolyte permeation and hydrogen gas removal. The chainmail catalysts of the N‐C‐NiFe are uniformly in situ assembled on the CNT “villi” using a rapid heat shock treatment. The high heating and quenching rates of the heat shock method lead to formation of the well‐dispersed ultrafine nanoparticles. The self‐supported wood‐based carbon framework decorated with the chainmail catalyst displays high electrocatalytic activity and superior cycling durability for hydrogen evolution. The unique heat shock method offers a promising strategy to rapidly synthesize well‐dispersed binary and polynary metallic nanoparticles in porous matrices for high‐efficiency electrochemical energy storage and conversion. The rapid in situ self‐assembly of the core‐shell N‐C‐NiFe nanoparticles in a porous carbonized wood‐based framework is first achieved using the heat shock treatment method. The self‐supported, low‐tortuosity wood‐based carbon framework decorated with the chainmail catalyst of N‐C‐NiFe displays high electrocatalytic activity and superior long‐term cycling stability for hydrogen generation.