CoFePBA Nanosheets on Carbon Nanotubes Coupled with Nickel-Encapsulated Carbon Tubules for Efficient and Highly Stable Overall Seawater Electrolysis

Abstract

The generation of H 2 by seawater electrolysis is limited by anodic chlorine corrosion and sluggish cathodic hydrogen evolution reaction (HER). Here, we report a simple approach for developing cobalt iron (CoFe)-based Prussian blue analogue with a nitrogen-doped carbon nanotube composite (CoFePBA/NCNT) and nickel-encapsulated carbon tubules (Ni/NCT) as oxygen evolution reaction (OER) and HER catalysts for overall seawater electrolysis utilizing graphite felt or carbon paper as the catalyst substrate, thus avoiding chlorine corrosion of the metal substrate. Instead of a commonly known hydrothermal method, a simple brush coating method was employed for catalyst coating which is feasible for large-scale electrolyzer fabrication. Our developed electrolyzer has shown a low overall seawater splitting voltage of 1.71 V and a good stability of 50 h in seawater with excellent selectivity for OER over hypochlorite formation at room temperature (26 °C). High OER activity is attributed to abundant catalytic sites provided by interconnected CoFePBA nanosheets and high intrinsic catalytic activity. Moreover, suppressed hypochlorite formation and corrosion resistance resulting from the synergistic effect of CoFePBA and NCNT make CoFePBA/NCNT||Ni/NCT a potential candidate for seawater electrolyzers. Our work paves a way to demonstrate seawater electrolyzer performance with nonprecious catalysts on a nonmetallic support.

Synergistic construction of an iron nitride embedded graphitic carbon nitride heterostructure electrocatalyst as a potential candidate to accelerate overall water electrolysis

“…S2,† where the CN stretching of pristine potassium ferrocyanide (CN-2040 cm −1 ) was unchanged after pyrolysis treatment (cyanide bridge with metal ions); however, the intensity was reduced and a similar peak reduction occurred in the –OH peak (3300–3500 cm −1 ). 45 A noticeable peak degradation was also observed in C–N/CN (1220 to 1700 cm −1 ) bonds (Fig. S2†).…”

Catalysts for Direct Seawater Electrolysis: Current Status and Future Prospectives

“…Therefore, it is necessary to employ electrodes and membranes that possess both high activity and corrosion resistance in the process of seawater electrolysis [23–27] . It is important to mention that recently there has been a dedicated effort focused on the development of electrodes that are both inexpensive and stable for seawater electrolysis [28–31] . One of the proposed strategies for stability enhancement employs a surface modification technique to fabricate a distinct physical protection layer or an electrostatic repulsion layer on the electrode‘s surface [15] .…”

“…[23][24][25][26][27] It is important to mention that recently there has been a dedicated effort focused on the development of electrodes that are both inexpensive and stable for seawater electrolysis. [28][29][30][31] One of the proposed strategies for stability enhancement employs a surface modification technique to fabricate a distinct physical protection layer or an electrostatic repulsion layer on the electrode's surface. [15] Given the notable advancements seen in saltwater electrolysis in recent years, there is a demand to merge the latest advancements in the design approach for the fabrication of corrosion-resistant electrodes in the context of seawater electrolysis.…”