Facile synthesis of Fe-doped CoP nanosheet arrays wrapped by graphene for overall water splitting

The development of durable, beneficial, and highly active non-precious metal-based electrocatalysts for hydrogen generation is a vital concern. This study proposes an effective strategy for the construction of Fe doped CoP nanosheet arrays wrapped by graphene (F_0.25CP-G) on nickel foam as an efficient electrocatalyst for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). In this design, the final catalyst possesses a combination of the high conductivity of graphene, great surface porosity, and the intrinsic electrocatalytic activity of the F_0.25CP-G which results in high-performance electrocatalytic activity toward the HER and OER. Therefore, the as-synthesized F_0.25CP-G catalyst can achieve overpotentials of 66 mV and 230 mV for the HER and OER, respectively, in KOH at 10 mA cm^-2. Furthermore, a practical electrolyzer (F_0.25CP-G||F_0.25CP-G) exhibits a current density of 10 mA cm^-2 at 1.60 V along with good durability for 24 h.

Conducting-Polymer Nanocomposites as Synergistic Supports That Accelerate Electro-Catalysis: PEDOT/Nano Co3O4/rGO as a Photo Catalyst of Oxygen Production from Water

This work describes how conducting polymer nanocomposites can be employed as synergistic supports that significantly accelerate the rate of electro-catalysis. The nanocomposite PEDOT/nano-Co3O4/rGO is discussed as an example in this respect, which is specific for photo electro-catalytic oxygen (O2) generation from water using light (PEDOT = poly (3,4-ethylenedioxythiophene); rGO = reduced graphene oxide). We show that the conducting polymer PEDOT and the conductive additive rGO may be used to notably amplify the rate of O2-generation from water by the nano catalyst, Co3O4. A composite film containing the precise molar ratio 7.18 (C; PEDOT):1 (Co):5.18 (C; rGO) exhibited high photocatalytic activity (pH 12) for the oxygen evolution reaction (OER) at 0.80 V (vs. Ag/AgCl), with a current density of 1000 ± 50 μA/cm2 (including a photocurrent of 500 μA/cm2), achieved after >42 h of operation under illumination with a light of intensity 0.25 sun. By comparison, the best industrial catalyst, Pt, yielded a much lower 150 μA/cm2 under the same conditions. Oxygen gas was the sole product of the reaction.

Formation of graphene encapsulated cobalt–iron phosphide nanoneedles as an attractive electrocatalyst for overall water splitting

Hierarchical CoFe–P nanoneedles encapsulated in the graphene texture are fabricated for water splitting applications.

Recent Advances of First d-Block Metal-Based Perovskite Oxide Electrocatalysts for Alkaline Water Splitting

First d-block metal-based perovskite oxides (FDMPOs) have garnered significant attention in research for their utilization in the water oxidation reaction due to their low cost, earth abundance, and promising activities. Recently, FDMPOs are being applied in electrocatalysis for the hydrogen evolution reaction (HER) and overall water splitting reaction. Numerous promising FDMPO-based water splitting electrocatalysts have been reported, along with new catalytic mechanisms. Therefore, an in-time summary of the current progress of FDMPO-based water splitting electrocatalysts is now considered imperative. However, few reviews have focused on this particular subject thus far. In this contribution, we review the most recent advances (mainly within the years 2014–2020) of FDMPO electrocatalysts for alkaline water splitting, which is widely considered to be the most promising next-generation technology for future large-scale hydrogen production. This review begins with an introduction describing the fundamentals of alkaline water electrolysis and perovskite oxides. We then carefully elaborate on the various design strategies used for the preparation of FDMPO electrocatalysts applied in the alkaline water splitting reaction, including defecting engineering, strain tuning, nanostructuring, and hybridization. Finally, we discuss the current advances of various FDMPO-based water splitting electrocatalysts, including those based on Co, Ni, Fe, Mn, and other first d-block metal-based catalysts. By conveying various methods, developments, perspectives, and challenges, this review will contribute toward the understanding and development of FDMPO electrocatalysts for alkaline water splitting.