The Ni(OH) ₂ hexagonal platelets were in situ fabricated on Ni foam as a binder-free supercapacitor electrode material with high performance and excellent cycling stability by a one-step, cost-effective, green hydrothermal treatment of three-dimensional (3D) Ni foam in a 15 wt% H ₂ O ₂ aqueous solution.

Nb₂O₅ with a negative charge can disrupt the rigid H-bond network on the surface of Ru nanoclusters, making it easier for free water molecules to reach the catalyst, thus accelerating the reactivity of hydrogen reduction.

{1̄11} faceted Ni ₃ S ₂ with an asymmetric zigzag structure is elaborately designed and fabricated, which exhibits remarkable electrocatalytic performance for the HER and OER.

Hemin-functionalized MoS₂ nanosheets (hemin/MoS₂-NSs) are first obtained via van der Waals interactions between few-layered MoS₂ nanosheets (MoS₂-NSs) and hemin molecules. It is demonstrated that a portion of MoS₂-NSs undergoes a phase transition from semiconducting to metallic phase under the influence of hemin, which shows the coexistence of semiconducting and metallic phases in the crystal structure of hemin/MoS₂-NSs. MoS₂-NSs prepared from sonication-induced exfoliation of bulk MoS₂ crystals in aqueous surfactant solution exhibit intrinsic peroxidase-like activity for the oxidation of 3,3,5,5-tetramethylbenzidine in the presence of H₂O₂, which is further improved by the functionalization of hemin. Significantly, MoS₂-NSs are presented as a new support of hemin, and when compared to MoS₂-NSs, hemin/MoS₂-NSs exhibit better dispersity in aqueous solution, which is used in the development of H₂O₂ sensor based on the enhanced peroxidase-like activity.

To enhance the capacitive property of NiO-based electrodes, O-vacancy-enriched NiO hexagonal platelets have been fabricated in situ on an Ni foam current collector by a facile hydrothermal treatment of Ni foam in a H₂O₂ aqueous solution and subsequent calcination in N₂ atmosphere. Due to the self-grown nature and the abundant oxygen vacancies, the as-prepared self-supported NiO electrode showed extraordinary pseudocapacitance. The specific capacitance of the as-prepared NiO electroactive materials was 2495 F g⁻¹ at a scan rate of 1 mV s⁻¹ (∼97% of the theoretical value of NiO) and the capacitance retention was higher than 80% when the current density increased from 0.5 to 10 A g⁻¹. DFT computational studies proved the vital role of oxygen vacancies in increasing the conductivity, electrochemical active sites and surface reactivity, which substantially account for the significantly high specific capacitance and rate capability. This study may further broaden the applications of NiO-based materials and boost the research on oxygen nonstoichiometry.