Mo‐Mediated Transition of the Lattice to Long‐Range Disorder Enables Ultra‐High Current Density Hydrogen Production at Low Potentials

Abstract

High-current hydrogen production at low potential toward hydrogen evolution reaction (HER) is a fatal factor restricting the large-scale production of green hydrogen. Here, a Mo-mediated nickel-based chalcogenides electrocatalyst (U-MoNiS) with long-range disordering through heterogeneous atom-mediated strategies, is proposed. The optimal U-MoNiS is scalable to meet the urgent application needs and it requires an extermely low overpotential (305 mV) to achieve ultra-high current density of 2243 mA cm -2 , which is 16.6-fold higher than the noble Pt/C (135 mA cm -2 ). Strikingly, the U-MoNiS can function well under an ultra-high current up to ~5 A. Operando experiments and calculations reveal the Mo-mediated transition of lattice model to a long-range disordering and regulate the microenvironment of dominant crystal plane, and the surface energy of ( 110) and ( 211) drops from 0.180 and 0.165 to 0.077 and 0.100 eV Å -2 , respectively. Which exceedingly minimizes the free energy barrier and then accelerates the H* adsorption, and fundamentally contributes to the achievement of efficient hydrogen production at high current density. The proposed strategy to produce hydrogen at ultra-high current would fulfill the dream to create 'a high effiective catalyst designed as simply as possible'.

2 A cm–2 Level Large-Scale Production of Hydrogen Enabled by Constructing Higher Capacity of Interface “Electron Pocket”

“…More information about the chemical state of the hybrid surface can be obtained by X-ray photoelectron spectroscopy (XPS) (Figure f–h). The Ni 2p region (Figure f) shows two predominant peaks of Ni 2+ (855.7 and 873.4 eV), two shakeup satellites at 862.0 and 880.1 eV, and two broadened peaks indicative of Ni 3+ at 875.5 eV (Ni 2p 1/2 ) and 857.8 eV (Ni 2p 3/2 ). ,− In addition, compared with B-Ni 3 S 2 and NM-IHJ, the characteristic peaks of NM-IHJ-V move toward higher binding energy as a whole, indicating the occurrence of an oxidation reaction. ,− The S 2p region of NM-IHJ-V (Figure g) possesses two strong signals at ∼168.5 and ∼169.8 eV, classified as S–O and S-vacancy (S-v) characteristic peaks, respectively, and the S-v content obtained by integrating the peak area is as high as 44.1%. However, no S-v peak was detected in B-Ni 3 S 2 , which further confirms that the generation of S-v is synchronized with the formation of an interface heterojunction. ,, Besides, the characteristic signals of S 2p 3/2 at ∼162.8 eV that were revealed in NM-IHJ-V (Figure g) are detected, and the S 2p 3/2 content decreases with the decrease of S content (NM-IHJ-V < NM-IHJ < B-Ni 3 S 2 < B-MoS 2 ), which means that S 2p 3/2 sacrifice will be replaced by more S-v formation (Table S1).…”

“…Thus, the industrial application goals for electrochemical hydrogen production need to meet both an excellent sustained active output and low overpotential at high current density. − Transition -metal chalcogenide heterojunctions exhibit certain activity toward EOWS, and although progress has been achieved in this field, most of the electrocatalysts currently reported only show a low current density (<1000 mA cm –2 ) and short-term stability. How to maintain the high activity of catalysts at superhigh current density (>1 A cm –2 ) to meet the stable operation of industry remains an urgent issue to be solved. − Typically, in EOWS systems, hydrogen evolution (HER) and oxygen evolution (OER) semireactions are involved, but both require overcoming high energy barriers to optimize kinetic progression (H*, *O, and *OOH) in the rapid step. ,,− …”

Non-precious metal-based catalysts for water electrolysis to produce H2 under industrial conditions

“…In another case, Mo mediates the lattice transition of MoNiS to long-range disorder, resulting in an optimal electronic structure and an ultra-high current density (2243 mA cm À2 ) of hydrogen evolution. 56 According to the XRD pattern of Fig. 14e, the lower peak intensity, higher half-peak In conclusion, crucial factors that contribute to achieving industrial current density are morphological regulation, electronic structure design, and reaction condition adjustment.…”

“…In another case, Mo mediates the lattice transition of MoNiS to long-range disorder, resulting in an optimal electronic structure and an ultra-high current density (2243 mA cm −2 ) of hydrogen evolution. 56 According to the XRD pattern of Fig. 14e, the lower peak intensity, higher half-peak width, and amorphous bulk Mo or MoS 2 in urchin-like MoNiS (U-MoNiS) indicate that Mo is mediated into Tri-Ni 3 S 2 , resulting in interface defects and distortion.…”

Rational design of efficient electrocatalysts for hydrogen production by water electrolysis at high current density

“…94,95 Cheng et al prepared the urchin-like Mo-incorporated Ni 3 S 2 (U-MoNiS) using the hydrothermal method. 91 The introduced Mo can change the lattice structure of tri-prism-like Ni 3 S 2 (tri-Ni 3 S 2 ) from long-range order to long-range disorder and induce lattice distortion (Fig. 8d).…”