Photocatalytic water splitting looks simple, catalyst in water, light on, hydrogen out, but the experiment stands or falls on whether the hydrogen is measured accurately. The reactor and the detector form one instrument, and beginners usually optimize one half while ignoring the other.
Use a leak-tested reactor with defined headspace, purge it with inert carrier to remove oxygen (oxygen both consumes product and poisons many catalysts), and only then start irradiation. The purge protocol belongs in your methods: how long, at what flow, verified how.
Calibrate the hydrogen detector with certified standards spanning the expected range, in the same carrier gas used in experiments. Verify calibration after any disassembly. Detection limits matter: a detector that cannot see below your early-stage production will report zero for hours of real chemistry.
First, sacrificial agents change the chemistry: state clearly whether runs are overall water splitting or half-reactions with scavengers, they are different claims. Second, temperature: irradiated suspensions heat, and apparent rates include thermal contributions. Third, stir rate changes mass transport and photon scattering, keep it fixed. Fourth, record cumulative production over time, not one endpoint, the rate curve is the data.
A clean run shows a smooth production curve with a stable rate after induction. Rates that fall across runs indicate deactivation; rates that jump indicate leaks or contamination. Reproduce each key run before believing it.
Perfectlight's water splitting setups pair sealed reactors with calibrated online hydrogen analysis; see solutions.
