Features of inorganic nanocrystals formation in conditions of successive ionic layers deposition in water solutions and the Co(II)Co(III) 2D layered double hydroxide synthesis

2D/2D Bi2MoO6/CoAl LDH S-scheme heterojunction for enhanced removal of tetracycline: Performance, toxicity, and mechanism

In this paper, the two-dimensional (2D) layered CoAl LDH (CoAl) was coupled with Bi2MoO6 (BMO) nanoplate and used for tetracycline (TC) degradation. Based on the results of UV-visible diffuse reflectance spectrum (UV-vis DRS), Motty-Schottky curves, and in situ X-ray photoelectron spectroscopy (XPS), a novel 2D/2D Bi2MoO6/CoAl LDH S-scheme heterojunction photocatalyst was built. The photodegradation rate constant of TC by the optimized sample BMO/CoAl30 was 3.637 × 10-2 min-1, which was 1.26 times and 4.01 times higher than that of Bi2MoO6 and CoAl LDH, respectively. The favorable photocatalytic performance of the heterojunction was attributed to the increased interfacial contact area of the 2D/2D structure. Besides, the transfer of photogenerated electrons from Bi2MoO6 to CoAl LDH under the effect of the built-in electric field (BIEF) reduced the recombination of photogenerated carriers and further improved the photocatalytic performance. The reactive species of h+, ·O2-, and 1O2 exhibited critical roles to degrade TC molecules by reactive radicals capture experiments and electron spin resonance (ESR) tests. The intermediate products of TC degradation and toxicity of intermediates were analyzed by liquid chromatography-mass spectrometer (LC-MS) and Toxicity Estimation Software Tool (T.E.S.T). Additionally, the BMO/CoAl composite photocatalysts showed high stability and environmental tolerance during the testing of cycles and environmental impacts with various water sources, organic contaminants, initial pH, and inorganic ions. This work provides a new protocol for designing and constructing novel 2D/2D S-scheme heterojunction photocatalysts for wastewater treatment.

Construction of Petal-Like Ag NWs@NiCoP with Three-Dimensional Core-Shell Structure for Overall Water Splitting

High-efficiency, good electrical conductivity and excellent performance electrocatalysts are attracting growing attention in the field of overall water splitting. In order to achieve the desirable qualities, rational construction of the structure and chemical composition of electrocatalysts is of fundamental importance. Herein, petal-like structure Ni0.33Co0.67P shells grown on conductive silver nanowires (Ag NWs) cores as bifunctional electrocatalysts for overall water splitting were synthesized through a facile hydrothermal method and phosphorization. The resultant three-dimensional core-shell petal-like structure Ag NWs@Ni0.33Co0.67P possesses excellent catalytic activities in alkaline conditions with the overpotential of 259 mV for the oxygen evolution reaction (OER), 121 mV for the hydrogen evolution reaction (HER) and a full cell voltage of 1.64 V to reach the current density of 10 mA cm-2. Highly conductive Ag NWs as cores and high surface area petal-like Ni0.33Co0.67P as shells can endow outstanding catalytic performance for the bifunctional electrocatalyst. Thus, the synthetic strategy of the three-dimensional core-shell structure Ag NWs@Ni0.33Co0.67P considerably advances the practice of Ag NWs toward electrocatalysts.

Porous urchin-like 3D Co(ii)Co(iii) layered double hydroxides for high performance heterogeneous Fenton degradation

Heterogeneous Fenton processes can overcome the generation of iron sludge and the production of more solid wastes.

Cobalt-based layered double hydroxides revisited: evidence for oxidizing radical generation

Layered double hydroxides (LDHs) containing transition metal elements such as cobalt show interesting reactivity related to the complexity of cobalt chemistry.