Recent Progress in Enhancing Photocatalytic Performance through Upconversion Process
Yuxi Xie, Jiaming Fan, Taoyi Wang, Jinzhen Liu, Hengqi Zhao, Shitong Wang, Jinsong Li, Zhaoyu Ma, Wenping Li, Junying Zhang
Abstract
Abstract The growing demand for energy and the urgency of mitigating environmental degradation and achieving carbon neutrality have created a critical need for renewable energy solutions. Photocatalysis offers a promising route to convert abundant solar energy into clean fuels, but conventional semiconductor photocatalysts only absorb UV light and partial visible light. One strategy to overcome this spectral limitation is to integrate upconversion materials that convert low‐energy near‐infrared photons into higher‐energy visible or UV photons, effectively broadening the light absorption range of photocatalytic systems. This review systematically compares diverse photon upconversion approaches, both lanthanide‐based (rare‐earth phosphors) and emerging non‐lanthanide mechanisms such as defect‐mediated sequential excitations, two‐photon absorption, and organic triplet‐triplet annihilation upconversion, and examines their integration with semiconductor photocatalysts. Structural design strategies (e.g., core‐shell nanostructures) and defect engineering are analyzed to illustrate how they improve light harvesting and charge separation. How these upconversion‐enhanced composites significantly boost solar‐driven reactions is discussed didcussed, notably water splitting for hydrogen production, CO 2 reduction, and pollutant degradation. Finally, key challenges and future directions are highlighted, including enhancing upconversion quantum efficiency, developing rare‐earth‐free upconversion systems, and optimizing interface engineering to maximize energy transfer and overall photocatalytic performance.