Multi‐Phase Heterostructure of CoNiP/Co_xP for Enhanced Hydrogen Evolution Under Alkaline and Seawater Conditions by Promoting H₂O Dissociation

Abstract

Hydrogen evolution reaction (HER) is a key step for electrochemical energy conversion and storage. Developing well defined nanostructures as noble‐metal‐free electrocatalysts for HER is promising for the application of hydrogen technology. Herein, it is reported that 3D porous hierarchical CoNiP/CoxP multi‐phase heterostructure on Ni foam via an electrodeposition method followed by phosphorization exhibits ultra‐highly catalytic activity for HER. The optimized CoNiP/CoxP multi‐phase heterostructure achieves an excellent HER performance with an ultralow overpotential of 36 mV at 10 mA cm−2, superior to commercial Pt/C. Importantly, the multi‐phase heterostructure shows exceptional stability as confirmed by the long‐term potential cycles (30,000 cycles) and extended electrocatalysis (up to 500 h) in alkaline solution and natural seawater. Experimental characterizations and DFT calculations demonstrate that the strong electronic interaction at the heterointerface of CoNiP/CoP is achieved via the electron transfer from CoNiP to the heterointerface, which directly promotes the dissociation of water at heterointerface and desorption of hydrogen on CoNiP. These findings may provide deep understanding on the HER mechanism of heterostructure electrocatalysts and guidance on the design of earth‐abundant, cost‐effective electrocatalysts with superior HER activity for practical applications.

Fabrication of Coral‐Shaped MoS2@Ni(Mn)VOX Electrocatalyst for Efficient Alkaline Hydrogen Evolution

“…As for the rate‐determining step of HER, the Tafel slopes of Volmer reaction, Heyrovsky reaction, and Tafel reaction are 120, 40, and 30 mV dec −1 , respectively. [ 59 ] As illustrated in Figure 6 a, the Tafel slope of MoS 2 @Ni(Mn)VO X is perceptibly smaller than that of NF, MoS 2 @NF, NiVO X , MoS 2 @NiVO X , and Ni(Mn)VO X . The small Tafel slope implies that the current density raises rapidly with the increase in overpotential, which indicates that the material has the fast conversion efficiency in HER.…”

Comprehensive Evaluation of Transition Metal Doped Ni3N to Construct High-Efficiency Hydrogen Evolution Catalyst

“…According to the D-band theory, shifting away from the Fermi level (down-shifting of the D-band center) mainly contributes to higher occupation of the anti-bonding states of catalysts, hence a weaker adsorption. 7 As shown in Fig. 4h, the increased valence band maximum indicates that ΔG of electrocatalysts after transition metal doping becomes smaller, thus bene ting for the desorption of intermediate and hydrogen.…”

“…5,6 Hydrogen evolution reaction (HER) provides a promising path to generate high-purity hydrogen toward energy and environmental sustainability. 7 Currently, one of the challenging issues in HER is to explore earth-abundant, long-term available, corrosion resistant, and e cient electrocatalysts for the practical application of hydrogen-energy technology. 8 Commercial noble metals (such as Pt and Ru) are the most remarkable HER electrocatalysts due to their unique electronic properties, low Gibbs free energy for desorption and adsorption of hydrogen and low energy barrier for splitting water molecules.…”

“…Seawater, which accounts for roughly 97% of the water volume on the earth, would be the most appropriate substitute for high purity freshwater in industrial production, and various anions and cations rich in seawater can also enhance the conductivity of the electrolyte. 3,12 However, unlike freshwater, the composition of seawater is very complex, and the high concentration of chloride ions will not only compete with the oxygen evolution reaction (OER) of the electrolyzed water at the anode to release chlorine, 7 but also severely corrode most of the catalysts containing metal elements. The highly corrosive hypochlorite by-products of chlorine evolution reaction (CER) will also block the active sites of the noble metal catalysts, and thus the noble metal catalysts for HER can not be used.…”

Modulating heterointerfaces of tungsten incorporated CoSe/Co3O4as a highly efficient electrocatalyst for overall water splitting

“…Researchers have devoted great effort to design effective electrocatalysts for promoting the active sites and Volmer step reaction in alkali water splitting using H + (proton) on the surface of the catalyst. 8,[34][35][36][37] For example, Zhang and co-workers presented the in situ surface reconstruction of a TiO 2 @CoCH composite which accelerates the HER kinetics by activating the surface and boosting the electrochemical performance in alkali media. 34 Liu et al established a multiphase CoNiP/Co x P heterostructure with unique kinetics helpful to enhance the water dissociation at the heterointerface and boost the hydrogen production.…”