Traditionally, adsorption is believed to take place only in the ground state, but here we report an excitation-driven adsorption mode. Composites of metallophthalocyanines and carbonaceous substrates are prepared, among which the potassium-phthalocyanine (KPc)/reduced graphene oxide (RG) composite shows the most typical behavior. Femtosecond transient absorption spectroscopy and first-principles simulations reveal that under ultraviolet (UV) irradiation, the excited electrons in the composite transfer efficiently from KPc to RG, leaving long-lived excited holes on KPc that enable selective adsorption of CO molecules. In the dark, the composite shows negligible CO adsorption (0.06 mmol g⁻1), whereas its CO uptake increases to 1.20 mmol g⁻1 upon UV light, with a UV-modulated adsorption capacity ratio of up to 95%. This adsorption mode is also applicable to other metallophthalocyanine/carbonaceous composites. This work presents a potential strategy for photoexcitation utilization and the development of energy-efficient chemical separation technologies. This study identifies excitation-mode adsorption on metallophthalocyanine/reduced graphene oxide composites. Strong interfacial interaction enables efficient UV-induced charge transfer, generating stable excited holes as new active adsorption sites.
Qi et al. (Tue,) studied this question.