The photocatalytic hydrogen production experiments were carried out using a custombuilt air-cooling apparatus for maintaining room temperature (22°C) and constant irradiation of the sample. Experiments were carried out in 21 mL Schlenk tubes capped with rubber septa. 10 mg of the CNx-based catalysts, which had been found to be the optimal loading determined in our previous study , was added to the Schlenk tube equipped with magnetic stirrer. The tube was evacuated and filled with argon. An H2O : MeOH (9 : 1, v/v) solution, with or without addition of additional sacrificial electron donor, was purged with argon. 10 mL of the degassed solution was added to the photocatalyst in the Schlenk tube under inert conditions and kept under constant irradiation from an LED source (λ = 420 nm; 51.3 mW cm -2 or λ = 470 nm; ca. 40 mW cm -2 ) in air-cooled photoreactors. The gas phase above the solution was probed by inserting a gas-tight GC syringe through the septum and the amount of hydrogen in the gas phase was quantified using headspace gas chromatography.