Sea coral-like NiCo₂O₄@(Ni, Co)OOH heterojunctions for enhancing overall water-splitting

Abstract

Efficient and low-cost sea coral-like NiCo2O4@(Ni, Co)OOH heterojunction catalysts meet the high current density requirements for industrial water electrolysis applications.

Self-Supporting Clusters Constituted of Nitrogen-Doped CoMoO4 Nanosheets for Efficiently Catalyzing the Hydrogen Evolution Reaction in Alkaline Media

“…To address the above issues, diverse modification methods have been explored to boost the HER performance of TMOs: (1) Elemental doping can efficiently accelerate the HER kinetics of TMOs by modulating the electronic structure and conductivity. , (2) Also, oxygen vacancy engineering can modulate electronic structure and free energy for H adsorption. , (3) Selectively exposing favorable crystal planes can obtain higher HER catalytic activity of TMOs. , (4) The construction of hierarchical heterostructure can enhance electrolyte diffusion and ionic transportation . Recently, bimetallic oxides of ABO 4 , in which A could be cobalt, nickel, copper, and iron of the II valence state and B could be molybdenum and tungsten of the VI valence state, reveal great potential for HER in the alkaline media due to their unique d electron configurations and more flexible redox properties than the corresponding individual metal oxides. , Among various chemical compositions and structures of ABO 4 , bimetallic cobalt molybdenum oxide (CoMoO 4 ) has been tentatively adopted as the possible HER catalyst due to the fact that Co- or/and Mo-based materials have shown desirable HER performance. − Unfortunately, pure CoMoO 4 still retains unsatisfactory HER performance on account of limited electrochemically active sites and a slow charge transfer rate, which must be urgently addressed . In the modification methods mentioned above, nonmetal elemental doping is a highly efficient and convenient method to optimize the electrochemical performance of TMOs by inserting a portion of heteroatoms into the as-prepared materials.…”

“…23 Recently, bimetallic oxides of ABO 4 , in which A could be cobalt, nickel, copper, and iron of the II valence state and B could be molybdenum and tungsten of the VI valence state, reveal great potential for HER in the alkaline media due to their unique d electron configurations and more flexible redox properties than the corresponding individual metal oxides. 24,25 Among various chemical compositions and structures of ABO 4 , bimetallic cobalt molybdenum oxide (CoMoO 4 ) has been tentatively adopted as the possible HER catalyst due to the fact that Co-or/and Mo-based materials have shown desirable HER performance. 26−33 Unfortunately, pure CoMoO 4 still retains unsatisfactory HER performance on account of limited electrochemically active sites and a slow charge transfer rate, which must be urgently addressed.…”

Doping β-CoMoO4 Nanoplates with Phosphorus for Efficient Hydrogen Evolution Reaction in Alkaline Media

“…Because of unique d electron configurations and high elemental abundance, Co and Mo have been the very frequent choices for constructing HER catalysts. 21 Their corresponding phosphides, 22−24 sulfides, 25 selenides, 26 nitrides, 27 and carbides 28 have been extensively investigated and proved to be promising candidates for catalyzing water reduction in alkaline electrolytes. Moreover, integrating those two elements into one material is quite likely to lead to a positive synergistic effect and thus give rise to striking HER performance.…”

“…Because of unique d electron configurations and high elemental abundance, Co and Mo have been the very frequent choices for constructing HER catalysts . Their corresponding phosphides, − sulfides, selenides, nitrides, and carbides have been extensively investigated and proved to be promising candidates for catalyzing water reduction in alkaline electrolytes.…”

In situ construction of porous hierarchical (Ni3-xFex)FeN/Ni heterojunctions toward efficient electrocatalytic oxygen evolution

“…This evolution is supported by the O 1s spectra, in which the intensity of -OH signal at 531.5 eV gets strong in reference to the case of lattice oxygen (529.8 eV) and adsorbed H2O (533.5 eV) (Fig. 4(f)) [40]. The corresponding N 1s signals at 397.8 eV for M-N (M = Ni, Fe) and at 399.9 eV for M-N-O become weaker and stronger, respectively, accompanied (c)-4(g)), in agreement with the initial oxidation peaks on the polarization curves upon applying the current followed by the OER activities (Fig.…”