Highly efficient photocatalytic hydrogen production by ZnCdS composite catalyst modified with NiCoP nanosheets prepared by LDH precursor

The unique characteristics and diverse applications of 2D transition metal phosphides have aroused significant interest. In this paper, we successfully prepared 2D NiCoP modified ZnCdS composite. The NiCoP nanosheets were successfully obtained by phosphating layered double hydroxide (LDH) precursor. The results show that the ZnCdS-8%NiCoP has the highest photocatalytic performance among all the composite photocatalysts with the H2 evolution rate of 1370.1 µmol h-1, which is 17.9 folds higher than obtained with pure ZnCdS. Detailed analysis reveal that NiCoP nanosheets functions as an excellent electron acceptor, speeding up the directed migration of electrons. Furthermore, the rational mechanism of photocatalytic has been presented based on density function theory (DFT) calculations, which is well congruent with experimental results. Our research offers a simple, environmentally benign, and scalable technique for making highly effective photocatalysts, as well as a novel perspective on transition metal phosphides rational design.

Synthesis of Bimetallic Ni-Co Phosphide Nanosheets for Electrochemical Non-Enzymatic H2O2 Sensing

NiCoP nanosheets (NSs) were successfully synthesized using the hydrothermal and high-temperature phosphorization process. The obtained NiCoP NSs were immobilized on a glassy carbon electrode (GCE) and used to construct a novel sensing platform for electrochemical non-enzymatic H₂O₂ sensing. Physicochemical characteristics of NiCoP NSs were obtained by field-emission scanning electron microscopy (FESEM), field-emission transmission electron microscope (FETEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). In addition, the electrochemical properties of NiCoP NSs were obtained by cyclic voltammetry (CV) and chronoamperometry (CA) towards the non-enzymatic detection of H₂O₂. FESEM and FETEM images provided a morphological insight (the unique nanosheets morphology of NiCoP) that could expose more active sites to promote mass/charge transport at the electrode/electrolyte interface. XRD and XPS results also confirmed the crystalline nature of the NiCoP nanosheets and the coexistence of multiple transitional metal oxidation states in NiCoP nanosheets. These unique physicochemical characteristics had a degree of contribution to ensuring enhancement in the electrochemical behavior. As a result, the synthesized NiCoP NSs composed of intercalated nanosheets, as well as the synergistic interaction between bimetallic Ni/Co and P atoms exhibited excellent electrocatalytical activity towards H₂O₂ electroreduction at neutral medium. As the results showed, the electrochemical sensing based on NiCoP NSs displayed a linear range of 0.05~4 mM, a sensitivity of 225.7 μA mM^-1 cm^-2, a limit of detection (LOD) of 1.190 μM, and good selectivity. It was concluded that NiCoP NSs-based electrochemical sensing might open new opportunities for future construction of H₂O₂ sensing platforms.