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

Abstract

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.

Metal Nanoclusters: New Paradigm in Catalysis for Water Splitting, Solar and Chemical Energy Conversion

“…In case of doped graphene, carbon nanotubes (CNTs), or a layered structure, heteroatoms (N, S, O, etc.) can usually increase the trapping ability of the support and thus can assist the uniform growth of MNCs . In the case of porous materials MNCs can reside in highly accessible 3D cavities, where the small MNCs are confined in the sub‐nanometer regime.…”

“…can usually increase the trappinga bility of the support and thus can assist the uniform growth of MNCs. [156] In the case of porousm aterials MNCs can reside in highly accessible 3D cavities, where the small MNCs are confined in the sub-nanometer regime. Generally,M OF/zeolite/ oxide support-based approaches can be categorized as "shipin-a-bottle" and "bottle-around-a-ship".…”

Crystalline Red Phosphorus Nanoribbons: Large‐Scale Synthesis and Electrochemical Nitrogen Fixation

“…Non-metallic materials are promising candidates for electrochemical nitrogen fixation under ambient conditions because they suppress competing hydrogen evolution during nitrogen reduction. [31][32][33][34] The electrochemical nitrogen fixation activity of cRP NRs is explored for the first time. A building unit of two coupled five atom rings from the bulk structure with (001) surface is adopted in the theoretical assessment (Figure 4 a).…”

Nanostructured Nickel Nitride with Reduced Graphene Oxide Composite Bifunctional Electrocatalysts for an Efficient Water-Urea Splitting

“…Therefore, through the electrolysis of water–urea waste water, we are able to significantly reduce environmental pollution and help efficiently produce hydrogen. The reactions of overall water–urea splitting to produce non-toxic nitrogen, carbon dioxide, and hydrogen are as follows [3,6,15,16,17,18,19,20]:CO(NH 2 ) 2 (aq) + 6OH − (aq) → N 2 (g) + 5H 2 O(l) + CO 2 (aq) + 6e − …”

“…In recent years, transition metal-based catalytic materials have attracted much attention thanks to their high electrochemical activity and stability. Non-noble metal-based Ni materials have been used as low-cost materials for water–urea splitting [20,21,22]. These exert an impressive catalytic effect in water–urea splitting as a result of multi-component synergistic effects, such as Ni–Co hydroxide [23], nickel hydroxide [24], Ni/WC [25], Ni–Rh [26] and nickel oxide [27].…”