Dandelion-Like CuCo2O4@ NiMn LDH Core/Shell Nanoflowers for Excellent Battery-Type Supercapacitor.

Dandelion-like CuCo2O4 nanoflowers (CCO NFs) with ultrathin NiMn layered double hydroxide (LDH) shells were fabricated via a two-step hydrothermal method. The prepared CuCo2O4@NiMn LDH core/shell nanoflowers (CCO@NM LDH NFs) possessed a high specific surface area (~181 m2·g-1) with an average pore size of ~256 nm. Herein, the CCO@NM LDH NFs exhibited the typical battery-type electrode material with a specific capacity of 2156.53 F·g-1 at a current density of 1 A·g-1. With the increase in current density, the rate capability retention was 68.3% at a current density of 10 A·g-1. In particular, the 94.6% capacity of CCO@NM LDH NFs remains after 2500 cycles at 5 A·g-1. An asymmetric supercapacitor (ASC) with CCO@NM LDH NFs//activated carbon (AC) demonstrates a remarkable capacitance of 303.11 F·g-1 at 1 A·g-1 with excellent cycling stability. The coupling and synergistic effects of multi-valence transition metals provide a convenient channel for the electrochemical process, which is beneficial to spread widely within the realm of electrochemical energy storage.

Boosting photocatalytic CO2 reduction via Schottky junction with ZnCr layered double hydroxide nanoflakes aggregated on 2D Ti3C2Tx cocatalyst.

Designing efficient photocatalysts is vital for the photoreduction of CO2 to produce solar fuels, helping to alleviate issues of fossil fuel depletion and global warming. In this work, a novel ZnCr-LDH/Ti3C2Tx Schottky junction is successfully synthesized using an in situ coprecipitation method. ZnCr-LDH nanoflakes collectively grow on the surface of Ti3C2Tx MXene nanosheets. When using Ti3C2Tx MXene as a cocatalyst in the prepared heterojunction, the light absorption intensity, photo-induced electron separation and migration efficiency increase. As a result, the composite ZnCr-LDH/Ti3C2Tx results in significant improvement in the performance of photocatalytic CO2 reduction under simulated solar irradiation. The optimized sample ZCTC25 has the highest photocatalytic CO2 reduction rates of 122.45 µmol g-1 CO and 19.95 µmol g-1 CH4 (after 6 h of irradiation). These values are approximately 2.65 times higher than those of pristine ZnCr-LDH. The product selectivity towards CO is 86%. This work provides a new method for the construction of novel 2D semiconductor photocatalysts and enriches the application of an unusual type of layered double hydroxides in the photoreduction of CO2.