Efficient and Stable Bifunctional Electrocatalysts Ni/Ni_xM_y (M = P, S) for Overall Water Splitting

Abstract

Development of easy-to-make, highly active and stable bifunctional electrocatalysts for water splitting is important for future renewable energy systems. Three-dimensional (3D) porous Ni/Ni 8 P 3 and Ni/Ni 9 S 8 electrodes are prepared by sequential treatment of commercial Ni foam with acid activation, followed by phosphorization or sulfurization. The resultant materials can act as self-supported bifunctional electrocatalytic electrodes for direct water splitting with excellent activity towards oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline media. Stable performance can be maintained for at least 24 h, illustrating their versatile and practical nature for clean energy generation. Furthermore, an advanced water electrolyzer through exploiting Ni/Ni 8 P 3 as both anode and cathode is fabricated, which requires a cell voltage of 1.61 V to deliver a 10 mA cm -2 water splitting current density in 1.0 M KOH solution. This performance is significantly better than that of the noble metal benchmarkintegrated Ni/IrO 2 and Ni/Pt-C electrodes. Therefore, these bifunctional electrodes have significant potential for realistic large-scale production of hydrogen as a replacement clean fuel to polluting and limited fossil-fuels.

Defect‐Rich Heterogeneous MoS2/NiS2 Nanosheets Electrocatalysts for Efficient Overall Water Splitting

“…[8,28,29] As for Ni 2p in Figure 3b, two obvious peaks at 872.9 and 855.4 eV are attributed to the Ni 2p 1/2 and Ni 2p 3/2 , as well two broad satellite peaks, demonstrating the presence of Ni 2+ . [30] Compared to pure NiS 2 , two peaks of Ni 2p 1/2 and Ni 2p 3/2 in MoS 2 /NiS 2 -3 are slightly shifted to higher binding energies (about 0.5 eV). It suggests the strong electronic interactions between NiS 2 and MoS 2 domains through established heterogeneous interfaces.…”

Extraction of nickel from NiFe-LDH into Ni2P@NiFe hydroxide as a bifunctional electrocatalyst for efficient overall water splitting

“…Therefore, a P-NiFe heterostructure can serve as an efficient bifunctional electrocatalyst for an alkaline electrolyzer, generating a cell voltage of only 1.51 V at 10 mA cm –2 in 1.0 M KOH solution, even better than the combination of the state-of-the-art IrO 2 and Pt/C as benchmark electrocatalysts. Though a number of NiFe-based metal hydroxides/oxides9a,12b–f,12h and transition-metal phosphides8a,8e,8f,8i,15 have been reported as electrocatalysts for OER and HER, to our knowledge, the selective extraction and phosphorization of a single metal from mixed metal hydroxides/oxides to form a heterostructure has not been documented so far. The in situ transformed Ni 2 P@NiFe hydroxide heterostructure not only enhances its conductivity due to the existence of metallic Ni 2 P, but also optimizes the adsorption energies for both HER and OER intermediates at the nickel active sites on its surface, thus dramatically enhancing its electrocatalytic activity for both OER and HER.…”

Small Upconverting Fluorescent Nanoparticles for Biosensing and Bioimaging

“…[ 43,45,46 ] For instance, the Yb/Tm co-doped NaGdF 4 nanoparticles had less emission loss when coated with a thin, inert surface layer of NaGdF 4 . [48][49][50] Core-Multiple Shell Layer Structure : Usually multiple shells include both inert and active layers, in which inert ones are intended to avoid undesirable interactions between active layers and active ones are designed to enhance interaction between different active domains. [48][49][50] Core-Multiple Shell Layer Structure : Usually multiple shells include both inert and active layers, in which inert ones are intended to avoid undesirable interactions between active layers and active ones are designed to enhance interaction between different active domains.…”