Electronic and Band Gap Engineering of Sn-Germanate Oxides for Environmental Photocatalysis

Humanity’s persistent dependence on non-renewable energy resources has intensified environmental degradation, driving the urgent need for clean and sustainable alternatives. Photocatalysis has gained significant attention as an environmentally friendly and energy-efficient strategy for addressing these challenges due to its low cost, material abundance, and ability to harness solar energy. Among the various classes of photocatalysts, perovskite oxides remain particularly attractive because of their exceptional structural flexibility and tunability in terms of chemical composition, band-gap width, oxidation states, and electronic configurations.

In the present work, we report the first comprehensive density functional theory (DFT) study on SnGeO₃ perovskite oxides, with a particular emphasis on the synergistic effects of high external pressure on their structural, mechanical, electronic, and photocatalytic responses. Our results demonstrate a pronounced pressure-induced modulation of the electronic structure, where the indirect band gap can be systematically reduced and shifted into the visible-light region, thereby significantly enhancing the material’s suitability for solar-driven photocatalysis and water-splitting processes. Additionally, calculated effective masses and band-edge positions indicate efficient charge-carrier separation and strong redox capability, both of which are essential for high photocatalytic performance. The predicted mechanical robustness and thermodynamic stability under compression further support the feasibility of synthesizing these materials experimentally.

Overall, this study identifies SnGeO₃ perovskites as promising candidates for next-generation sustainable photocatalysts and highlights pressure engineering as an effective pathway for tailoring their functional properties.