The measurement of pH provides evidence supporting the accumulation of excited states over time through irradiation (Figure ). The pH of the 71 mM mPAH in aqueous solution decreased from 5.3 to 5.0 within 3 minutes under light exposure (Figure , top). Upon turning off the light, the pH gradually returned to 6.2 within 30 minutes. Subsequently, mPAH buffer system at pH 7 was irradiated and the recorded pH shows gradual decrease of pH from 7.0 to 6.85 over 15 min. pH reverted back to its starting value when the light was turned off (Figure , middle). This small pH change can be attributed to the buffering effect provided by the ground state of mPAH (pKa 7.8). Measurement of pH in the presence of 100 mM of K2CO3 saturated under 15% CO2 presented a gradual increase in pH while irradiated and decrease in pH under dark, which is consistent with the proposed photochemical working scheme (Figure , bottom). A light on and off experiment further confirms the essential role of light in CO2 release (Figure ). Although preliminary, the results indicate that the extended half-life of the excited state of Liao's photoacid provided stable CO2 release during irradiation. In a cyclic experiment comprising 3 cycles, each cycle resulted in a CO2 output of 0.07 mmol. Further investigations are necessary to explore potential enhancements in CO2 release capacity using alternative strategies. In summary, we have developed a photochemical carbon capture strategy in an aqueous bicarbonate buffer system, utilizing the unique properties of photoacids and their response to light. Our study focused on the photochemical modulation of the hydrophilic pyranine molecule as a model system for carbon capture. Control experiments verified the contribution of the photoacid effect, along with a photothermal effect, to CO2 release. Cyclic experiments demonstrated the feasibility of the system over 5 cycles.