Engineering Mn-Doped CdS Thin Films Through Chemical Bath Deposition for High-Performance Photoelectrochemical Water Splitting.

Doping conventional materials with a second element is an exciting strategy for enhancing catalytic performance via electronic structure modifications. Herein, Mn-doped CdS thin films were successfully synthesized with the aid of the chemical bath deposition (CBD) by varying the pH value (8, 10, and 12) and the surfactant amount (20, 40, 60 mg). Different morphologies like nano-cubes, nanoflakes, nano-worms, and nanosheets were obtained under different deposition conditions. The optimized Mn-doped CdS synthesized at pH=8 exhibited better photoelectrochemical (PEC) performance for oxygen evolution reaction (OER) than pure CdS films, with a maximum photocurrent density of 300 µA/cm2 at an external potential of 0.5 V, under sunlight illumination. The observed performance is attributed to the successful Mn doping, porosity, high surface area, and nanosphere morphology.

Enhanced Electrocatalytic Activity of Amorphized LaCoO3 for Oxygen Evolution Reaction.

Amorphous inorganic perovskites have attracted significant attention as efficient electrocatalysts due to their unique structural flexibility and good catalytic activity. In particular, the disordered structure and a surface rich in defects such as oxygen vacancies can contribute to the superior electrocatalytic activity of amorphous oxides compared to their crystalline counterpart. In this work, we report the synthesis of LaCoO3 , followed by an amorphization process through urea reduction with tailored modifications. The as-synthesized catalysts were thoroughly tested for their performance in oxygen evolution reaction (OER), Remarkably, the amorphous LaCoO3 synthesized at 450 °C (referred to as LCO-4) exhibits excellent OER catalytic activity. At an overpotential of 310 mV, it achieved a current density of 10 mA/cm-2 , exceedingly fast to 1 A/cm-2 at an overpotential of only 460 mV. Moreover, LCO-4 exhibited several advantageous features compared to pristine LaCoO3 and LaCoO3 amorphized at other two temperatures (350 °C, LCO-3, and 550 °C, LCO-5). The amorphized LCO-4 catalyst showed a higher electrochemically active surface area, a key factor in boosting catalytic performance. Additionally, LCO-4 demonstrated the lowest Tafel slope of 70 mVdec-1 , further highlighting its exceptional OER activity. Furthermore, the long-term stability of LCO-4 is notably superior than pristine LaCoO3 (LCO-P) and the other amorphized samples (LCO-3 and LCO-5). The enhanced catalytic activity of LCO-4 can be attributed to its unique disordered structure, small crystallite size, and higher concentration of oxygen vacancies in the final catalyst.

NiCo2O4 nano-needles as an efficient electro-catalyst for simultaneous water splitting and dye degradation.

Developing an efficient and non-precious bifunctional catalyst capable of performing water splitting and organic effluent degradation in wastewater is a great challenge. This article reports an efficient bifunctional nanocatalyst based on NiCo2O4, synthesized using a simple one-pot co-precipitation method. We optimized the synthesis conditions by varying the synthesis pH and sodium dodecyl sulfate (SDS) concentrations. The prepared catalyst exhibited excellent catalytic activity for the electrochemical oxygen evolution reaction (OER) and simultaneous methylene blue (MB) dye degradation. Among the catalysts, the catalyst synthesized using 1 g SDS as a surfactant at 100 °C provided the highest current density (658 mA cm-2), lower onset potential (1.34 V vs. RHE), lower overpotential (170 mV @ 10 mA cm-2), and smallest Tafel slope (90 mV dec-1) value. Furthermore, the OH˙ radicals produced during the OER electrochemically degraded the MB to 90% within 2 hours. The stability test conducted at 20 mA cm-2 showed almost negligible loss of the electrochemical response for OER, with 99% retention of the original response. These results strongly suggest that this catalyst is a promising candidate for addressing the challenges of wastewater treatment and energy generation.

Facile Synthesis of PdO.TiO2 Nanocomposite for Photoelectrochemical Oxygen Evolution Reaction.

The rapid depletion of fossil fuels and environmental pollution has motivated scientists to cultivate renewable and green energy sources. The hydrogen economy is an emerging replacement for fossil fuels, and photocatalytic water splitting is a suitable strategy to produce clean hydrogen fuel. Herein, the photocatalyst (PdO.TiO2) is introduced as an accelerated photoelectrochemical oxygen evolution reaction (OER). The catalyst showed significant improvement in the current density magnitude from 0.89 (dark) to 4.27 mA/cm2 (light) during OER at 0.5 V applied potential. The as-synthesized material exhibits a Tafel slope of 170 mVdec-1 and efficiency of 0.25% at 0.93 V. The overall outcomes associated with the photocatalytic activity of PdO.TiO2 demonstrated that the catalyst is highly efficient, thereby encouraging researchers to explore more related catalysts for promoting facile OER.

Recent progress in the design, synthesis and applications of chiral metal-organic frameworks.

Chiral Metal-Organic Frameworks (CMOFs) are unique crystalline and porous class of materials which is composed of organic linkers and metal ions. CMOFs surpass traditional organic and inorganic porous materials because of their tunable shape, size, functional diversity, and selectivity. Specific applications of CMOFs may be exploited by introducing desired functional groups. CMOFs have chiral recognition abilities, making them unique for chiral compound synthesis and separation. The CMOFs can be synthesized through different approaches. Two main approaches have been discussed, i.e., direct and indirect synthesis. Synthetic strategies play an essential role in getting desired properties in MOFs. CMOFs find potential applications in adsorption, asymmetric catalysis, luminescence, degradation, and enantioselective separation. The MOFs' porosity, stability, and reusability make them an attractive material for these applications. The plethora of applications of CMOFs have motivated chemists to synthesize novel MOFs and number of MOFs have been ever-escalating. Herein, the synthetic methods of CMOFs and their various applications have been discussed.