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^–1_Pt and the specific activity of 0.64 mA cm^–2_ECSA, 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^–1_Pt) 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.