ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Tailoring the optoelectronic and photocatalytic properties of MgH₂ through Sr and Ca doping for sustainable energy technologies

Hamza Errahoui, Mohamed Karouchi, Anass Bakour, Abdelkebir Ejjabli, Aymane El Haji, Abdelmounaim Laassouli, Youssef Lachtioui, and Omar Bajjou

Laboratory of Engineering in Chemistry and Physics of Matter Faculty of Sciences and Technics, Sultan Moulay Slimane University, Beni Mellal, Morocco

E-mail: hamzaerrahoui@gmail.com

Abstract:

Utilizing density functional theory (DFT), we thoroughly investigate the optoelectronic and photocatalytic properties of pristine MgH₂, as well as its Sr and Ca doped variants, uncovering structure-property relationships through first-principles computational analysis. The analysis of the electronic structure, conducted via the density of states (DOS) and partial density of states (PDOS), revealed that Sr and Ca doping significantly reduce the bandgap of MgH₂ from 3.804 eV to 2.804 eV and 2.629 eV, respectively. Additionally, this doping transformation alters the material’s bandgap from direct to indirect. Pristine MgH₂ exhibits an optical absorption onset at approximately 3.8 eV with a maximum absorption peak at 6.77 eV. Upon Sr and Ca doping, the absorption edge shifts toward lower photon energies (2.8 eV and 2.6 eV, respectively), with enhanced absorption intensities reaching 2.12 × 10⁵ cm⁻¹ at 8.75 eV for Sr-doped MgH₂ and a peak around 7.88 eV for Ca-doped MgH₂. Optical characterization via dielectric function components, optical conductivity, and energy loss function further reveals a clear modulation of light absorption mechanisms in the doped material systems through quantitative spectroscopic analysis. The photocatalytic analysis demonstrated that doping enhances visible light absorption and modifies the band edge positions, thus influencing reduction and oxidation processes. Sr doped MgH₂, with a conduction band edge of -0.102 eV, is optimized for reduction reactions, while Ca doped MgH₂, with a conduction band edge of 0.005 eV, exhibits higher potential for oxidation reactions. These improvements make Sr and Ca doped MgH₂ promising candidates for hydrogen storage, water splitting, and the degradation of organic pollutants under visible light irradiation. This study highlights the effectiveness of Sr and Ca doping in tuning the electronic, optical, and photocatalytic properties of MgH₂, paving the way for applications in energy conversion technologies and environmental remediation.

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-026-04727-3

Chemical Papers 80 (5) 5541–5558 (2026)