Free-Standing 3D Porous N-Doped Graphene Aerogel Supported Platinum Nanocluster for Efficient Hydrogen Production from Ammonia Electrolysis

Ammonia oxidation reaction (AOR) is an environmentally friendly electrochemical technology for hydrogen production. Nowadays, exploiting low-costing, high-performance and robust catalysts for AOR is essential to improve the overall efficiency of ammonia electrolysis cell (AEC). Here, we report the synthesis and characterization of a novel free-standing three-dimensional (3D) porous N-doped graphene aerogel (NGA) anchored with Pt nanocluster (Pt/NGA) monolithic material as a high-performance and robust electrocatalyst for hydrogen production from AEC. The NGA substrate was facilely fabricated through a self-assemble process into the randomly arranged 3D porous backbone structure with graphene oxide (GO) and poly(oxypropylene)diamine D400 as precursors in a pure water solvent. Then, the Pt nanocluster-like structures were uniformly dispersed and embedded onto NGA through the simple electrodeposition method. The as-prepared Pt/NGA monolithic materials exhibited a higher ammonia electro-oxidation activity with the mass activity of 1.77 mA μg–1Pt and the specific activity of 0.64 mA cm–2ECSA, due mainly to the uniformly dispersed Pt nanocluster-like morphology, the improved electrical conductivity, the 3D porous NGA networks as well as the N-doping structure in graphene framework. When the 3D Pt/NGA monolith was directly used as working electrodes of AEC, a considerable hydrogen volume of 8.5 mL (about 1.90 mL mg–1Pt) was produced at 0.8 V in 3 h. This novel free-standing 3D porous NGA monolith is expected to be a potential and promising material for application in the fields of electrocatalysis and electrochemical energy transform.