2D Layered Double Hydroxides for Oxygen Evolution Reaction: From Fundamental Design to Application

2D transition metal carbides or nitrides, known as MXenes, are a new family of 2D materials with close to 30 members experimentally synthesized and dozens more theoretically investigated. Because o...

MXene/Polymer Membranes: Synthesis, Properties, and Emerging Applications

Embedding cubane [M4 (OH)4 ] (M=Ni, Co) clusters within the matrix of metal-organic frameworks (MOFs) is a strategy to develop materials with unprecedented synergistic properties. Herein, a new material type based on the pore-space partition of the cubic primitive minimal-surface net (MOF-14-type) has been realized. CTGU-15 made from the [Ni4 (OH)4 ] cluster not only has very high BET surface area (3537 m2  g-1 ), but also exhibits bi-microporous features with well-defined micropores at 0.86 nm and 1.51 nm. Furthermore, CTGU-15 is stable even under high pH (0.1 m KOH), making it well suited for methanol oxidation in basic medium. The optimal hybrid catalyst KB&CTGU-15 (1:2) made from ketjen black (KB) and CTGU-15 exhibits an outstanding performance with a high mass specific peak current of 527 mA mg-1 and excellent peak current density (29.8 mA cm-2 ) at low potential (0.6 V). The isostructural cobalt structure (CTGU-16) has also been synthesized, further expanding the application potential of this material type.

Bi‑Microporous Metal–Organic Frameworks with Cubane [M 4 (OH) 4 ] (M=Ni, Co) Clusters and Pore‑Space Partition for Electrocatalytic Methanol Oxidation Reaction

A Simple Synthetic Strategy toward Defect‐Rich Porous Monolayer NiFe‐Layered Double Hydroxide Nanosheets for Efficient Electrocatalytic Water Oxidation

Single-atom catalysts (SACs) have emerged as one of the most promising alternatives to noble metal-based catalysts for highly efficient oxygen reduction reaction (ORR). While SACs can offer notable benefits in terms of lowering overall catalyst cost, there is still room for improvement regarding catalyst activity. To this end, we designed and successfully fabricated an ORR electrocatalyst in which atomic clusters are embedded in an atomically dispersed Fe-N-C matrix (FeAC@FeSA-N-C), as shown by comprehensive measurements using aberration-corrected scanning transmission electron microscopy (AC-STEM) and X-ray absorption spectroscopy (XAS). The half-wave potential of FeAC@FeSA-N-C is 0.912 V (versus reversible hydrogen electrode (RHE)), exceeding that of commercial Pt/C (0.897 V), FeSA-N-C (0.844 V), as well as the half-wave potentials of most reported non-platinum-group metal catalysts. The ORR activity of the designed catalyst stems from single-atom active centers but is markedly enhanced by the presence of Fe nanoclusters, as confirmed by both experimental measurements and theoretical calculations.

Markedly Enhanced Oxygen Reduction Activity of Single-Atom Fe Catalysts via Integration with Fe Nanoclusters

Controllable growth of NiSe nanorod arrays via one-pot hydrothermal method for high areal-capacitance supercapacitors

Electrocatalysts with outstanding performance have been highly desired toward exploration of new energy storage and conversion devices/systems as well as making an efficient and eco-friendly utilization of green energy. In this study, we composed an iron-based binary diselenide-derived oxide (Fe-SDO) with a facile one-step hydrothermal method to utilize the earth-abundant iron and the probably prosperous catalytic performance of metal-selenides compounds. The catalyst exhibits an overpotential of 226 mV at a current density of 10 mA/cm2, a Tafel slope of 41 mV dec-1, and robust durability after catalyzing vigorous OER for 36 h constantly. Through several analytical methods conducted before and after the oxygen evolution reaction activation on FeSe2 it was discovered that such catalyst possessed a morphology as "Cuju"-like balls with porosity inside in which we explored the vacancy defects and lattice distortion that play significant roles in generating the high electrocatalytic performance of our proposed catalyst by inducing remarkable electron conductivity in the porous Cuju balls (a Chinese traditional football). Throughout our work the superb electrocatalyst performance of the iron-based compounds was demonstrated, and subsequently the underlying reason for such electrocatalyst performance was addressed, which may push boundaries for the exploration of iron-based compounds as OER catalyst and large-scale commercial application of such compounds in the future.

“Cuju”-Structured Iron Diselenide-Derived Oxide: A Highly Efficient Electrocatalyst for Water Oxidation

Nickel-iron diselenide hollow nanoparticles with strongly hydrophilic surface for enhanced oxygen evolution reaction activity

Electrochemically splitting water into hydrogen and oxygen plays a significant role in the commercialization of hydrogen energy as well as fuel cells, but it remains a challenge to design and fabricate low-cost and high-efficiency electrocatalysts. Herein, we successfully prepared Ni3Se2/MoSex on nickel foam via a facile electrodeposition method. To understand the electrochemical mechanism occurring in the electrodeposition process, a new model was proposed, providing insight into the nucleation and growth of deposited materials. The as-prepared Ni3Se2/MoSex exhibits splendid electrochemical performance with 82 mV and 270 mV overpotentials to drive a current density of 10 mA cm−2 in 1 M KOH aqueous solution for HER and OER, respectively. Moreover, a driving potential of 1.57 V is required to reach a current density of 10 mA cm−2 for a configured full cell with Ni3Se2/MoSex working as both the anode and cathode towards overall water splitting, outperforming the state-of-the-art commercial full cells assembled with noble-based metals. The advanced catalytic performance should be attributed to the numerous in situ formed interfaces, allowing π-electron transfer from Ni to Mo via O2− bridging, subsequently optimizing the adsorption features of oxygenated species (OER) and favorable Volmer/Heyrovsky reaction (HER). This work offers an effective and scalable fabrication prototype for the preparation of bifunctional electrocatalysts with electrodeposition.

Zhaoxi Yang

Papers

2D Layered Double Hydroxides for Oxygen Evolution Reaction: From Fundamental Design to Application

Controllable growth of NiSe nanorod arrays via one-pot hydrothermal method for high areal-capacitance supercapacitors

“Cuju”-Structured Iron Diselenide-Derived Oxide: A Highly Efficient Electrocatalyst for Water Oxidation

Nickel-iron diselenide hollow nanoparticles with strongly hydrophilic surface for enhanced oxygen evolution reaction activity

Electrodeposition of Ni3Se2/MoSex as a bifunctional electrocatalyst towards highly-efficient overall water splitting.