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In this paper, the effect of C, N and O atom doping of intrinsic MoSe₂ on the adsorption capacity of Ni is investigated based on first-principle research methods. The aim is to analyze whether intrinsic MoSe₂ can be doped and modified to improve its adsorption capacity of Ni so that it can be used as a new type of adsorbent material. By calculating and analyzing the energy band structure, density of states, differential charge and optical properties of each system, the conclusions are as follows: the O-doped MoSe₂ system has the best adsorption capacity for Ni, and the adsorption capacities of the three systems are in the following order: O>N>C. The bandgap value of intrinsic MoSe₂ adsorbed Ni-atom decreases, while the Fermi energy level of the C-doped MoSe₂ adsorbed Ni-atom system is located in the valence band, which shows p-type doping. The differential charge of the system was analyzed and the charge transfer of the adsorbed system was increased by C, N and O atom doping, and the O-doped system had the strongest adsorption capacity for Ni. It was shown that the charge distribution between the system and the adsorbed Ni-atom changed considerably after atomic doping, and the bonds between the Ni-atom and the dopant atoms of the C-, N- and O-doped adsorption system were strongly ionic. Optical analysis reveals that C, N and O atom doping improves the charge binding ability of Ni-adsorbed MoSe₂ material, which gives it a higher polarization rate and faster electric field response. The absorption of ultraviolet light is greatly enhanced, which can improve the efficiency of solar cells and convert solar energy into electricity more effectively. Overall, the Ni adsorption capacity of atomically doped MoSe₂ is improved, indicating that doping can be an effective means to improve the adsorption of Ni-atom by intrinsic MoSe₂. It is hoped that the research results in this paper can provide some theoretical guidance for the application of MoSe₂ in optoelectronic devices.

In this study, the effect of alkaline-earth metal element doping on the photoelectric properties of intrinsic MoSe₂ is systematically investigated based on the first-principles approach, and it is believed that the findings of this work will give some theoretical guidance for future research on MoSe₂ doping modification. The results show that all the doping systems exhibit good stability, and Be atom doping has the lowest formation energy value, making the doping easier to produce. The doping of alkaline-earth metal elements resulted in some lattice distortion of MoSe₂. Intrinsic MoSe₂ is a semiconductor with a direct bandgap of 1.498eV, and the doping of alkaline-earth metal elements causes the bandgap value to decrease in each system, and the bandgap is the smallest when Be is doped. All doped systems exhibit P-type conducting properties. Compared with the intrinsic MoSe₂, all doped systems have their conduction band fraction moved to the low-energy direction overall, and new density of states peaks appear near the Fermi energy level. These state density peaks mainly originate from the results contributed by the s-orbitals of each doping system Mo-4d, Se-4p, and each dopant atom. The analysis of the work function reveals that the work function of each doped system is smaller than the intrinsic MoSe₂, then the energy required for the occurrence of electron leaps is reduced, which improves the electron mobility of the doped system. The Mulliken Population analysis shows that stable chemical bonds are formed between the doped alkaline-earth metal elements and the surrounding Se atoms. The examination of the optical characteristics demonstrated that, in comparison to the intrinsic MoSe₂, all doped systems’ greatest dielectric absorption peaks were attenuated and moved toward the low-energy region; the doping of alkaline-earth metal elements broadened the light absorption edge of the intrinsic MoSe₂. The absorption peaks of each doping system are shifted toward the low-energy region with the red-shift phenomenon, and the light absorption is good in the ultraviolet region.

In this research, a series of catalysts based on MoSe₂ were synthesized by the hydrothermal method and used for the catalytic hydrogenation of alkali lignin for the first time. For 4wt.% NiSe₂/MoSe₂ catalyst, at 290${}^{\circ }$C, under 2MPa H₂ pressure for 1.5h, the conversion of alkali lignin and the yield of bio-oil reached 96.47% and 93.68%, respectively. In addition, the composition of the product (bio-oil) was analyzed via Fourier transform infrared (FTIR) spectrometry, gas chromatography-mass spectrometry (GC-MS) spectra, and proton nuclear magnetic resonance (¹HNMR) spectra. Finally, our study demonstrated that those MoSe₂-based composite catalysts can effectively degrade the biomass into bio-oil containing valuable chemical products.