Ni(OH)₂‐WP Hybrid Nanorod Arrays for Highly Efficient and Durable Hydrogen Evolution Reactions in Alkaline Media

Abstract

The development of efficient non-noble-metal hydrogen evolution electrocatalysts in alkaline media is crucial for sustainable, ecofriendly production of H through water electrolysis. An alkaline hydrogen evolution reaction (HER) catalyst composed of Ni(OH) -decorated thungsten phosphide (WP) nanorod arrays on carbon paper was synthesized by thermal evaporation and electrodeposition. This hybrid catalyst displayed outstanding HER activity and required a low overpotential of only 77 mV to obtain a current density of 10 mA cm and a Tafel slope of 71 mV dec . The hybrid catalyst also showed long-term electrochemical stability, maintaining its activity for 18 h. This improved HER efficiency was attributed to the synergetic effect of WP and Ni(OH) : Ni(OH) effectively lowers the energy barrier during water dissociation and also provides active sites for hydroxyl adsorption, whereas WP adsorbs hydrogen intermediates and efficiently produces H gas. This interfacial cooperation offers not only excellent HER catalytic activity but also new strategies for the fabrication of effective non-noble-metal-based electrocatalysts in alkaline media.

Triple Functions of Ni(OH)2 on the Surface of WN Nanowires Remarkably Promoting Electrocatalytic Activity in Full Water Splitting

“…12,25 The peak of 531.3 eV in the O 1s window (Figure 2d) is associated with the lattice O of Ni(OH) 2 . 11,12 Notably, more tungsten oxides were formed on the surface of WN, with the decrease of the peaks of the W−N bond (W 4f 7/2 at 32.3 eV, W 4f 5/2 at 34.4 eV, and N 1s at 397.5 eV) and the increase of the peaks of the oxidation states of W (W 5+ : W 4f 7/2 at 34.8 eV and W 4f 5/2 at 36.9 eV; W 6+ : W 4f 7/2 at 35.4 eV and W 4f 5/2 at 37.5 eV). For comparison, the XPS spectrum of WN-Ni(OH) 2 -KOH (WN-Ni(OH) 2 treated with 1 M KOH for 2 h) is exhibited in Figure 2.…”

“…The variation of the electronic structure of W, N, and Ni confirms the non-negligible electronic interactions between WN and Ni(OH) 2 , leading to the activity variation of WN around the interface. 11,12,14,27,28 2.2. Electrocatalytic Activity of WN-Ni(OH) 2 in Alkaline HER.…”

Applications of Nickel‐Based Electrocatalysts for Hydrogen Evolution Reaction

“…[ 72 ] In view of the extensive room for improvement in the catalytic performance of Ni(OH) 2 (250 mV), Yong proved that Ni(OH) 2 can reduce the energy barrier of the water decomposition step using a hybrid comprising Ni(OH) 2 and WP nanorods (in alkaline media). [ 73 ] Subsequently, Liu et al designed a Ni/Ni(OH) 2 dual‐composition electrocatalyst on nickel foam, considering the weak H adsorption on Ni. Coral‐like Ni/Ni(OH) 2 with a 3D layered structure was prepared by a two‐step electrodeposition process.…”

N-doped mixed Co, Ni-oxides with petal structure as effective catalysts for hydrogen and oxygen evolution by water splitting

“…The iR correction was applied to all data. The experimental potentials were converted to RHE with the equation E (RHE) ¼ E (calomel) + (0.219 + 0.0591 Â pH)V. 21 LSV measurements were performed in H 2 -saturated 1.0 M KOH solution at a scan rate of 5 mV s À1 .…”