Engineering defects in TiO2 for the simultaneous production of hydrogen and organic products

Photoreforming ethanol to simultaneously produce hydrogen and value-added organic products was realized over defected TiO2. Chemically induced defects in TiO2 promoted light absorption and charge separation, enhancing overall photoactivity. The induced defects also regulated product selectivity, leading to greater hydrogen purity and liquid to gaseous carbon ratio. The optimal catalyst generated 0.08 mmol/hr of hydrogen with a purity greater than 99 % and 0.08 mmol/hr of liquid acetaldehyde over a 6 hr timeframe. This was three times greater than the untreated TiO2. Active species trapping revealed that the preferred ethanol oxidation pathway was direct hole transfer, indicating the selectivity relies on surface chemisorption. Surface defects decreased the acetaldehyde adsorption energy, instigating its prompt desorption and suppressing overoxidation into CO2, thus improving the selectivity towards hydrogen and liquid hydrocarbon products. The work offers an alternative approach towards sustainable energy by coupling photocatalysis with waste organic utilization.

Automated summary

Photoreforming ethanol over defected TiO2 enables simultaneous generation of hydrogen and value-added organic products. The induced defects enhance light absorption and charge separation, improving overall photoactivity. They also regulate product selectivity, leading to higher hydrogen purity and liquid to gaseous carbon ratio. The work presents a sustainable energy approach by combining photocatalysis with waste organic utilization.