Carbon Nanodots for All-in-One Photocatalytic Hydrogen Generation

Carbon nanodots (CNDs) were photochemically altered to produce dihydrogen under light irradiation. Within the complex structure of CNDs, photo-oxidation takes place at citrazinic acid molecular fluorophore sites. Important is the fact that the resulting CND materials have a dual function. On one hand, they absorb light, and on the other hand, they photo- and electrocatalytically produce dihydrogen from water and seawater, without any external photosensitizer or cocatalyst. Record HER activities of 15.15 and 19.70 mmol(H-2) g(catalyst)(-1) h(-1) were obtained after 1 h of 75 mW/cm(2) Xe lamp illumination, from water and seawater, respectively. This impressive performance outweighs the remaining structural uncertainties. A fullfledged physicochemical investigation based on an arsenal of steady-state and time-resolved spectroscopic characterizations together with microscopy enabled a comprehensive look into the reaction mechanism. For an efficient dihydrogen formation, a precatalytic activation by means of reduction with a sacrificial electron donor is imperative.

Automated summary

The study found that carbon nanodots can produce dihydrogen gas under light irradiation and have a dual function of light absorption and dihydrogen production without the need for external assistance. Through in-depth physicochemical research, it was discovered that precatalytic activation through reduction with a sacrificial electron donor is crucial for efficient dihydrogen formation.