External Quantum Efficiencies EQEs were measured using LEDs controlled by an IsoTech IPS303DD power supply. The platinum loaded photocatalysts (12 mg) were suspended in aqueous ascorbic acid (0.1 M, 8 mL). An area of 8 cm 2 was illuminated and the light intensity was measured with a ThorLabs S120VC photodiode power sensor controlled by a ThorLabs PM100D Power and Energy Meter Console. The external quantum efficiencies were estimated using the equation below: