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Electrodes capable of electrocatalytically splitting seawater sustainably (≥500 h) at industrially acceptable current density (≥400 mA/cm2 at an overpotential of ≤0.6 V) and fabricated utilizing sustainable and scalable procedures are desirable to promote the commercialization of electrolyzer technology for green H2 production. Herewith, we report transition-metal nitride nanoparticle-encapsulated in situ-grown nitrogen-doped carbon (NC)-layered FeOOH-based heterostructures on nickel foam (NC-Ni3Nm/Fe3Nm) as bifunctional electrodes for the electrocatalytic splitting of seawater. The Ni3N/Fe3N nanoflake-encapsulated NCs are synthesized in a one-pot procedure using a sustainable route devoid of ammonia and other harsh reducing agents. Polyacryloyl hydrazide is utilized as the reducing and capping agent for the synthesis of metal nanoparticles, followed by the corresponding Ni3N-encapsulated NC under moderate temperature conditions. The procedure allows control over the metal loading and size of Ni3N nanoflakes in the heterostructures. The generality of the approach is supported by synthesizing Ni3N- and Fe3N-based heterostructures, which may be extended to other mono- and bimetallic systems. NC-Ni3N21 exhibited a bifunctional behavior (ηOER @ 100 mA/cm2 = 0.32 V, and ηHER @ 100 mA/cm2 = 0.29 V) toward the electrocatalytic splitting of seawater in the presence of 1 M KOH. The electrode displayed sustainability (≥700 h) at a fairly high current density (400 mA/cm2) in seawater under alkaline conditions.

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In this article, we present the formation of nitrogen (N) doped graphene oxide nanospheres (N-GONs) and investigate their applicability for photocatalytic water splitting. We chose a simple "bottom-up" method for synthesizing N-GONs. Dibenzopyrrole as a basic structural unit was used for constructing N-GONs. Nitration is an intermediate step, subsequent hydrothermal treatment of nitro derivatives imparted oxygen functionalities, which was well proved via CHNS and XPS analysis. ∼ 14 % and 39 % of nitrogen and oxygen were present inside N-GONs. The average size of N-GONs is in-between 30-80 nm. N-GONs typically have a band gap of nearly 2.61 eV. The valance and the conduction bands alignments of N-GONs w.r.t to standard hydrogen electrode were evaluated through UPS and XPS studies. The alignments were found to be well suited for H 2 O splitting applications. N-GONs have n-type semiconductor features and a charge carrier density of 1.12 × 10 22 cm À 3 . While studying photocatalytic dissociation of water we identified oxygen as the only product. Significantly, 1 g of N-GONs produced ∼ 1.3 mmol of oxygen over the course of 1 h. These backgrounds clearly suggest the possibilities of ongoing oxygen reduction and oxygen evolution reactions simultaneously. No-significant traces of H 2 O 2 were observed which suggested immediate H 2 O 2 disproportionation to O 2 and H 2 O on N-GONs. The proposed photocatalytic activity of N-GONs is also confirmed by RRDE method for ORR catalysis.