Photocatalytic degradation research has attracted significant attention in the wake of the increasingly severe global challenge of water pollution. In this study, nano-ZnO was synthesized through a straightforward method using zinc acetate anhydrous as the precursor. The experimental results revealed that annealing conditions significantly influenced the bandgap energy (Eg) of ZnO, with a positive correlation observed between the intensity of photoluminescence (PL) spectra and photocatalytic activity. Under optimal annealing conditions at 300 °C for 1.5 h, the photocatalytic degradation efficiency of methylene blue (MB) exceeded 98% within 40 min of ultraviolet (UV) irradiation, surpassing the efficiencies reported for ZnO in recent studies. This high performance underscores the excellent photocatalytic activity of the synthesized ZnO samples. Furthermore, after five photocatalytic cycles, the degradation efficiency of MB remained above 90%, and the crystalline structure of the ZnO samples remained stable, demonstrating their exceptional structural stability during the photocatalytic process. Additionally, this study examined the effects of stirring conditions and different light sources on MB degradation, providing valuable insights for future research in related fields.

Cobalt disulfide (CoS₂) features highly active catalytic sites and is regarded as a promising candidate for electrocatalytic hydrogen evolution. In this study, molybdenum-doped cobalt disulfide (CoS₂:Mo) was synthesized via a facile hydrothermal approach. XRD analysis confirms that the obtained samples crystallize in a cubic pyrite structure, with diffraction peaks consistently shifting towards lower angles. SEM characterization reveals that the samples exhibit microrod-like morphologies with an average size of approximately 1 μm. Integrated analyses from XRD, XPS, and EDS mapping demonstrate that Mo is uniformly distributed across the surface and successfully doped into the CoS₂ lattice. Electrochemical measurements indicate that the CoS₂:Mo sample delivers a low overpotential of 122 mV and a Tafel slope of 128 mV dec⁻¹ at a current density of 10 mA cm⁻² in alkaline media, significantly surpassing the performance of pure CoS₂ and MoS₂. Moreover, the CoS₂:Mo exhibits an enhanced double-layer capacitance, with a C_dl value of 2.72 mF cm⁻², superior to that of pure CoS₂ (1.63 mF cm⁻²) and MoS₂ (0.31 mF cm⁻²). Mo doping enhances conductivity and active sites, thereby boosting electrocatalysis. This work presents an effective strategy for the development of cost-efficient and high-performance non-precious metal electrocatalysts.