Anchoring of Ni₁₂P₅ Microbricks in Nitrogen- and Phosphorus-Enriched Carbon Frameworks: Engineering Bifunctional Active Sites for Efficient Water-Splitting Systems

Abstract

The demand for developing high-efficiency multifunctional electrocatalysts with a long-term stability rapidly increases for achieving the commercialization of sustainable hydrogen (H 2 ) production via cost-effective water electrolysis systems. This study describes single-phase metal-rich nickel phosphide (Ni 12 P 5 )-incorporated carbon composites for a highly efficient water-splitting system. The distinct Ni 12 P 5 is anchored in nitrogen (N)-and phosphorus (P)-rich carbon matrices (Ni 12 P 5 @N,P-C); the creation of the matrices entails a facile hydrothermal-followed pyrolysis treatment to explore their bifunctional activities in the water-splitting system. Owing to the superior activity of the rich Ni (δ + ) component for the production of molecular oxygen and that of P (δ − )and N species in the carbon framework for hydrogen adsorption, the optimized Ni 12 P 5 @N,P-C composites contribute effectively toward both high oxygen evolution and hydrogen evolution reactions. Consequently, the Ni 12 P 5 @N,P-C composite-based two-electrode water-splitting system shows a low operating potential of 1.57 V at 10 mA cm −2 and achieves the commercially required high current density of 500 mA cm −2 at a stable potential of 2 V. The functionalization of composite electrocatalysts based on strategical engineering and the intrusion of multiple active sites can help develop enhanced electrochemical energy systems.

Synergistic Coupling of Hierarchical Heterostructured Ni3P/Ni/VN Microflower Electrocatalyst for Enhanced Hydrogen Evolution Reaction

“…This demonstrated that the Ni site exerted electron donor properties and the metal Ni could act as a bridge for electron transfer between Ni 3 P and VN. Additionally, from the P 2p spectrum presented in Figure 3d, the P 2p of Ni 3 P/Ni/VN@NC could be distinguished by the featured peaks located at 128.48 and 129.59 eV, attributing to the P 2p 3/2 and P2p 1/2 species, respectively, together with the signature peak centered at 133.04 eV allocated to the P−O species due to the partial oxidation of the material surface [53–54] . Interestingly, the peaks of P 2p for Ni 3 P/Ni/VN@NC were shifted towards higher binding energy in comparison to Ni 3 P/Ni@NC, signifying that the P site behaved as an electron donor.…”

Sulphur Assisted Nitrogen‐Rich CNF for Improving Electronic Interactions in Co‐NiO Heterostructures Toward Accelerated Overall Water Splitting

“…The overall OER mechanism is shown in Equation 9. [ 57 ] The CoNiO heterostructures with oxygen vacancies and electron deficient sites in the interface endow a large number of active sites for OER. The N‐CNF presents a higher density of states near the Fermi level that alters the electron density in the carbon matrix.…”

Heterostructured mixed metal oxide electrocatalyst for the hydrogen evolution reaction

“…Easier water dissociation is promoted by synergistic effects at the interfaces. The charge transfer induced from the interfaces enables weakened reactant adsorption, hence preventing surface poisoning from the bonded reactants ( Janani et al, 2022 ; Surendran et al, 2022 ), resulting in easier hydrogen adsorption and desorption.…”