Hierarchical Porous Prism Arrays Composed of Hybrid Ni–NiO–Carbon as Highly Efficient Electrocatalysts for Overall Water Splitting

Abstract

Searching for an economical and efficient water splitting electrocatalyst is still a huge challenge for hydrogen production. This work reports one-step synthesis of hierarchical porous prism arrays (HPPAs) composed of Ni–NiO nanoparticles embedding uniformly in graphite carbon (Ni–NiO/C HPPAs), which is derived from metal–organic framework (CPO-27-Ni) prism arrays grown on nickel foam (NF). Remarkable features of the prism arrays, synergistic effect of Ni–NiO/C, porous graphite carbon, high conductive NF, and good contact between catalyst and current collector result in excellent electrocatalytic performance of Ni–NiO/C HPPAs@NF. Ni–NiO/C HPPAs@NF shows a small overpotential of ∼49.48 mV at the current density of 10 mA cm–2, low Tafel slope of 74 mV dec–1 and robust stability for hydrogen evolution reaction (HER) in alkaline media. Especially, the overpotential for HER of Ni–NiO/C HPPAs@NF is only ∼132 mV at the current density of 185 mA cm–2, almost the same as the value from the Pt/C. Furthermore, for oxygen evolution reaction in basic media, Ni–NiO/C HPPAs@NF shows better catalytic activity, lower Tafel slope and higher durability than precious IrO2. The above finding offers an effective strategy to design the bifunctional electrocatalysts for overall water splitting.

Boosting Lattice Oxygen Oxidation of Perovskite to Efficiently Catalyze Oxygen Evolution Reaction by FeOOH Decoration

“…With this intention, we focus on the key step of LOM based on our previous studies [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35], a OHfilling pathway, as shown in the following formulas {½O = O-MO 4 → ½V-MO 4 + e − } and {½V-MO 4 + OH − → ½HO ads -MO 4 + e − }, where M, [MO 4 ], and V denote the transition metal B site of perovskite, the surface structure with oxygen vacancies, and O vacancy, respectively. Some studies have demonstrated that OHfilling is thermodynamically favorable in some perovskite and plays a key role in LOER [36].…”

One‐Step Synthesis of NiFe Layered Double Hydroxide Nanosheet Array/N‐Doped Graphite Foam Electrodes for Oxygen Evolution Reactions

“…[7] Consequently, it is urgent to develop non-precious metals or earth-abundant elements based electrocatalysts requiring relatively low overpotentials to initiate OER. [8][9][10][11][12] As reported, low-cost transition metals and their derivatives, especially Ni based oxides, [13,14] hydroxides, [15,16] sulfides, [17][18][19] and phosphides [20,21] have been indicated as favorable candidates for water splitting because of their earth abundance and high catalytic performance characteristics. Among these candidates, NiFe layered double hydroxide (LDH) catalysts have been attracting more and more research attention in electrocatalysis because of their special nanostructure, tunable composition, and large specific surface area.…”

Immobilization of Fe-Doped Ni2P Particles Within Biomass Agarose-Derived Porous N,P-Carbon Nanosheets for Efficient Bifunctional Oxygen Electrocatalysis

“…The outstanding electrocatalytic performance of Fe-Ni 2 P@N,P-CNSs toward OER and ORR can be ascribed to the structural and composition features as follows: (i) the strong coupling effect between the well-dispersed Fe-Ni 2 P particles and conductive porous carbon nanosheets, which is facile for the exposure of more active sites (Hu et al, 2016; Lei et al, 2018); (ii) the introduction of N and P in the carbon matrix, by which the electronic structure of the applied carbon support is effectively modified, creates more available defects with enhanced catalytic activity and durability (Huang et al, 2018; Wei et al, 2018); (iii) the large specific surface area of Fe-Ni 2 P@N,P-CNSs, which provides numerous accessible catalytic sites, and endows available infiltration to the electrolyte for effective O 2 bubble evolution and a reductive reaction over the electrode surface (Fu et al, 2018e; Zhou et al, 2018). By taking advantage of these exceptional structural merits and the synergistic effect between the multi-components, the as-prepared Fe-Ni 2 P@N,P-CNSs display impressive catalytic activity and stability toward both OER and ORR.…”