The first step in conducting a photocatalytic experiment is the construction of the reaction system. Typically, researchers disperse a pre-synthesized semiconductor powder catalyst in a solution containing a specific solvent and a sacrificial agent at a designated mass ratio (e.g., 30 mg). Sacrificial agents such as methanol, triethanolamine (TEOA), or sodium sulfide solution function by capturing photo-generated holes or electrons, thereby suppressing bulk recombination of photogenerated carriers and allowing researchers to focus on the half-reaction kinetics of hydrogen or oxygen evolution. Under the stirring action, these particles form a uniform suspension in the liquid phase, maximizing surface area for photon capture and ensuring that each active site participates in the chemical bond cleavage of water molecules.
Among all experimental details, degassing the system and establishing a vacuum environment are critical for data reliability. Because the hydrogen and oxygen produced in photocatalytic water splitting are usually at the micromolar (μmol) level, oxygen penetration from ambient air (approximately 21%) can severely interfere with full water-splitting experiments. Therefore, a core step in the experimental procedure is the deep evacuation of the sealed reaction system using a high-performance vacuum pump. In this context, the μGAS1000 micro-gas reaction evaluation system demonstrates its value as a precision research platform. Through integrated software control, the system can achieve an absolute vacuum of ≤0.5 kPa, eliminating reading deviations caused by ambient temperature and humidity fluctuations in conventional differential pressure gauges. By performing multiple vacuum–inert gas (e.g., argon) cycles, the system’s dead volume is thoroughly purified, laying the physical foundation for accurately calculating the theoretical stoichiometric ratio of hydrogen and oxygen evolution.
The illumination stage is the practical step of energy conversion. Researchers typically use a solar simulator as a stable light source and install cutoff filters (e.g., Cut 420) to restrict the incident photon energy range, allowing the calculation of the system’s apparent quantum yield (AQY). During the experiment, strong light irradiation can heat the liquid phase; thus, maintaining a constant temperature water circulation (e.g., 15°C) is crucial not only to preserve the catalyst's kinetic stability but also to prevent water condensation from entering expensive gas chromatographic detectors. Modern equipment such as the μGAS1000 integrates temperature control layers with the reactor chamber, offering high heat transfer efficiency and ensuring a highly uniform experimental environment under prolonged irradiation.
Detection and data analysis of the products mark the final stage of the experimental process. Traditional offline sampling with needles, which cannot exclude air interference and offers low temporal resolution, is increasingly being replaced by automated online detection. In the μGAS1000 system, patented sampling valve island technology is used; its minimal moving parts and superior sealing effectively prevent micro air ingress during valve switching. Coupled with the built-in passive magnetic fan pump, the gas products achieve uniform kinetic distribution within just 10 minutes under strong unidirectional circulation, ensuring that every sample delivered to the gas chromatograph is highly representative. Real-time monitoring via PC software enables researchers to obtain standard curve regressions with R² > 0.999 and export complete reports covering hydrogen evolution rate, pressure evolution, and environmental parameters, facilitating paperless and scientifically managed experimental records.
In summary, a rigorous experimental procedure for photocatalytic water splitting is a critical step for translating laboratory mechanistic exploration into Hydrogen Farm-scale engineering applications. From the chemical proportioning of sacrificial agents to maintaining high-vacuum physical environments, and to automated online analysis based on patented valve island technology, every optimization eliminates systemic “noise.” By integrating a digitally capable evaluation platform, scientists can precisely track the journey of each photon. This strict pursuit of experimental rigor is a core driving force for advancing breakthroughs in green hydrogen research and reshaping the global energy industry.
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