Stable oxygen vacancies engineered via microenvironment-regulated diglyceryl ether decomposition for solar-driven clean water generation

Abstract

Rich oxygen vacancies (OVs) in a semiconductor are crucial for solar-driven water purification. Herein, we report an eco-friendly and energy-efficient strategy to fabricate mesoporous black TiOC with high concentrations of both surface and bulk OVs. Our approach leverages the microenvironment-regulated decomposition of diglyceryl ether (D100)—a biomass-derived derivative of glycerol—during the low-temperature calcination of polymeric coordination gels. We demonstrate that the coordination microenvironment dictates the D100 decomposition pathway: the oxygen-rich surface facilitates complete oxidation to generate surface OVs, while the oxygen-deficient interior directs the dehydration and aromatization–condensation of D100 and yields aromatic carbon doping and the associated stable bulk OVs. The resulting TiOC-2 material exhibits broad-spectrum absorption spanning the UV-vis-NIR region and enhanced non-radiative recombination, achieving a rapid photothermal temperature rise of over 20 °C within only 90 seconds. When integrated into a self-floating aerogel (TiOC@SA–TiOC), the system achieves a high solar evaporation rate of 2.61 kg m⁻² h⁻¹ under 1 sun illumination. This work pioneers a green and scalable approach for the direct conversion of bio-based chemicals into high-performance, multifunctional semiconductors, addressing critical needs in the energy–water nexus.