Electrocatalytic Oxygen Evolution with an Atomically Precise Nickel Catalyst

Study of the Oxygen Evolution Reaction Catalytic Behavior of CoxNi1-xFe2O4 in Alkaline Medium

Catalysts for the oxygen evolution reaction (OER) play an important role in the conversion of solar energy to fuel of earth-abundant water into H₂ and O₂ through splitting/electrolysis. Heterogeneous electrocatalysts for hydrogen and oxygen evolution reactions (HER and OER) exhibit catalytic activity that depends on the electronic properties, oxidation states, and local surface structure. Spinel ferrites (MFe₂O₄; M = Ni and Co) based materials have been attractive for the catalytic water oxidation due to their well-known stability in alkaline medium, easy synthesis, existence of metal cations with various oxidation states, low cost, and tunable properties by the desired metal substitution. To understand the better catalytic activity of MFe₂O₄ in detail the role of Ni and Co was studied through M_xNi_1-xFe₂O₄ (M = Co; 0 < x < 1), which was prepared by the sol-gel method. The results showed that bare NiFe₂O₄ has better catalytic activity (η = 381 mV at 10 mA cm^-2 and Tafel slope of 46.4 mV dec^-1) compared to Co-containing M_xNi_1-xFe₂O₄ (η = 450-470 mV at 10 mA cm^-2 and Tafel slope of 50-73 mV dec^-1) in alkaline medium, and the substitution of Co is found to suppress the catalytic activity of NiFe₂O₄. The degradation of catalytic activity with an increase in Co content was accounted for in further detailed investigations.

Ultra-fast and highly sensitive enzyme-free glucose biosensing on a nickel–nickel oxide core–shell electrode

Ultra-fast (∼1 s) and highly sensitive (1889.8 μA mM⁻¹ cm⁻²) enzyme-free glucose biosensing on a unique NiNiO core–shell electrode.

Electrocatalysis for the oxygen evolution reaction: recent development and future perspectives

We review the fundamental aspects of metal oxides, metal chalcogenides and metal pnictides as effective electrocatalysts for the oxygen evolution reaction.

Highly stable and efficient Pd6(SR)12 cluster catalysts for the hydrogen and oxygen evolution reactions

Atomically precise Pd₆(SC₁₂H₂₆)₁₂ sub-nanometre sized clusters are synthesized and they show high electrocatalytic activities for the hydrogen and oxygen evolution reactions.

Visible-Near-Infrared-Light-Driven Oxygen Evolution Reaction with Noble-Metal-Free WO2-WO3 Hybrid Nanorods

Understanding and manipulating the one half-reaction of photoinduced hole-oxidation to oxygen are of fundamental importance to design and develop an efficient water-splitting process. To date, extensive studies on oxygen evolution from water splitting have focused on visible-light harvesting. However, capturing low-energy photons for oxygen evolution, such as near-infrared (NIR) light, is challenging and not well-understood. This report presents new insights into photocatalytic water oxidation using visible and NIR light. WO₂-WO₃ hybrid nanorods were in situ fabricated using a wet-chemistry route. The presence of metallic WO₂ strengthens light absorption and promotes the charge-carrier separation of WO₃. The efficiency of the oxygen evolution reaction over noble-metal-free WO₂-WO₃ hybrids was found to be significantly promoted. More importantly, NIR light (≥700 nm) can be effectively trapped to cause the photocatalytic water oxidation reaction. The oxygen evolution rates are even up to around 220 (λ = 700 nm) and 200 (λ = 800 nm) mmol g^-1 h^-1. These results demonstrate that the WO₂-WO₃ material is highly active for water oxidation with low-energy photons and opens new opportunities for multichannel solar energy conversion.

A Molecular Ni-complex Containing Tetrahedral Nickel Selenide Core as Highly Efficient Electrocatalyst for Water Oxidation

We report the highly efficient catalytic activity of a transition metal selenide-based coordination complex, [Ni{(SePⁱ Pr₂ )₂ N}₂ ], (1) for oxygen evolution and hydrogen evolution reactions (OER and HER, respectively) in alkaline solution. Very low overpotentials of 200 mV and 310 mV were required to achieve 10 mA cm^-2 for OER and HER, respectively. The overpotential for OER is one of the lowest that has been reported up to now, making this one of the best OER electrocatalysts. In addition, this molecular complex exhibits an exceptionally high mass activity (111.02 A g^-1 ) and a much higher TOF value (0.26 s^-1 ) at a overpotential of 300 mV. This bifunctional electrocatalyst enables water electrolysis in alkaline solutions at a cell voltage of 1.54 V.