O poder do sol na palma da mão: perspectivas homogêneas e heterogêneas acerca da transferência de hidrogênio fotocatalítica

Abstract

Accounting for approximately 25% of all industrial processes, conventional catalytic hydrogenation relies on gaseous hydrogen, which is predominantly produced through steam methane reforming, as well as elevated temperatures and pressures. In this context, photocatalytic transfer hydrogenation emerges as a refined approach, utilizing solar energy to promote the in situ hydrogen transfer from donor molecules directly to unsaturated substrates through visible-light-active catalysts. This review provides an overview of recent advances in photocatalytic hydrogen transfer from the perspectives of both homogeneous and heterogeneous systems, highlighting the main catalyst design strategies and potential bridges between these fields. The discussion was conducted through a review of published articles between 2020 and 2026 on molecular hydrogen-free photocatalytic hydrogenation processes. The analyzed studies demonstrated that homogeneous systems excel in asymmetric catalysis, enabling fine control over enantioselectivity with complete atomic efficiency, whereas heterogeneous systems offer advantages related to stability, recyclability, high conversion rates within shorter reaction times. Among these approaches, single-atom catalysis emerges as a promising strategy for integrating high atomic efficiency, characteristic of molecular systems, with the robustness of semiconductor materials. Finally, a growing trend can be observed in both fields towards the use of water as the ideal hydrogen source, driven by its abundance, low cost, and sustainability.