In the field of gas–solid photocatalysis research—such as CO₂ reduction, ammonia synthesis, and VOCs degradation—the rigor of data is the cornerstone of scientific outcomes. To ensure that every researcher can obtain accurate and highly reproducible experimental results using the PLC-GDHC I Gas Diffusion Multiphase Continuous Catalytic Reaction Platform, we have specially compiled this standardized operating procedure, aiming to safeguard your research safety and efficiency.
01: Electrical Safety
The equipment includes electrical components such as LED light sources and vacuum pumps. Ensure proper grounding before operation. Do not use in a humid environment.
02: Light Source Safety
The LED light source has a high power density. Never look directly at the quartz window when the light source is on, to avoid eye injury from intense light or ultraviolet radiation.
03: Mechanical and Burn Safety
During operation, the reactor and pipelines may reach high temperatures. Wear heat-resistant gloves when disassembling. When using chain clamps, apply force evenly to avoid crushing glass components.
04: Vacuum and Pressure Safety
The system operates under vacuum and low-pressure conditions. Ensure all pipelines are securely connected, and perform vacuuming and gas filling smoothly.
05: Personal Protection
Laboratory coats, safety goggles, and appropriate protective gloves must be worn during operation.
01: Catalyst Loading and Film Preparation
Disperse the powdered catalyst ultrasonically in a solvent to form a uniform suspension. Place the standard 35 mm diameter porous hydrophobic membrane into a Büchner funnel as the filtration layer. Pour the catalyst suspension into the Büchner funnel in multiple portions for vacuum filtration, ensuring uniform catalyst loading on the membrane. Dry the catalyst-loaded membrane thoroughly for later use.
02: Assembly of the Reactor Upper Chamber
Place the PTFE inner ring in the center of the reactor upper chamber (aluminum alloy). Fit the thin O-ring onto the PTFE inner ring, then place the PTFE outer ring over the O-ring. Cover with the quartz window and secure it to the reactor upper chamber using chain clamps. (Apply uniform clamping force; do not overtighten.)
03: Assembly of the Reactor Lower Chamber
Add no more than 10 mL of reaction solution to the reactor lower chamber (high-borosilicate glass). Snap the PTFE membrane base into the inner wall of the lower chamber. Place the dried catalyst/porous hydrophobic membrane assembly onto the membrane base, with the hydrophobic side (lower surface) facing downward and in contact with water. Insert the PTFE membrane press cover, fit the O-ring around the outside of the membrane base, and place the PTFE outer ring outside the O-ring.
04: Integration of the Upper and Lower Reactor Chambers
Align the assembled upper chamber with the lower chamber, then secure the entire reactor using chain clamps. (Apply uniform clamping force; do not overtighten.)
05: Connecting the Reactor to the System
Connect the inlet gas line of the reactor lower chamber to the pipeline labeled “IN” on the left side of the system. Connect the outlet gas line of the reactor upper chamber to the pipeline labeled “OUT” on the right side of the system.
Connect the circulating water interface of the reactor lower chamber to the low-temperature thermostatic bath and turn on the bath.
01: Initial State Confirmation
Confirm that the six-port valve is in the “Sampling” position, the four-port valve is in the “Sampling” position, and the three-way valve is in the “Experiment” position. Close the gas flow rate adjustment valve on the left panel of the system, and turn off the solenoid valve and gas diffusion circulator switches.
02: Vacuuming
Turn on the vacuum pump, system power, and gas diffusion circulator. Slowly adjust the circulator speed knob to low-speed operation. Gradually rotate the three-way valve to the “Vacuum” position. When the system pressure gauge reaches its minimum value, rotate the three-way valve back to the “Experiment” position.
03: Gas Filling
Turn on the solenoid valve switch and rotate the three-way valve to the “Gas Filling” position. Slowly adjust the gas flow rate valve. When the system pressure gauge reads “0,” close the gas flow rate valve and rotate the three-way valve back to the “Vacuum” position. Repeat the vacuum–filling process at least three times to completely remove air from the system.
04: Atmosphere Control
After the final gas filling brings the pressure back to “0,” rotate the three-way valve to the “Experiment” position. Rotate the four-port valve to the “Vacuum” position, set the gas flow rate valve to maximum, and turn off the solenoid valve and vacuum pump.
Adjust the gas diffusion circulator speed knob to medium speed. Adjust the motorized lift of the light source so that the LED light source is positioned at an appropriate distance directly above the quartz window. Turn on the light source power, then press the “R/S” button on the motorized lift to illuminate the LED light source and begin the experiment.
Proceed with the following steps only after the gas chromatograph baseline has stabilized:
1. Turn on the vacuum pump. At this time, the four-port valve should be in the “Vacuum” position and the six-port valve in the “Sampling” position. Hold for 5 minutes.
2. Rotate the four-port valve to the “Sampling” position to collect the sample. Hold for 5 minutes.
3. Rotate the six-port valve to the “Injection” position and immediately start “Data Acquisition” on the gas chromatograph. Then rotate the four-port valve to the “Vacuum” position.
4. After 2 minutes, rotate the six-port valve back to the “Sampling” position and turn off the vacuum pump.
1. Press the “R/S” button on the motorized lift to turn off the LED light source, switch off the light source power, and raise the motorized lift to its highest position.
2. Rotate the three-way valve to the “Gas Filling” position. Slowly adjust the gas flow rate valve until the system pressure gauge reads “0.” Turn off the gas flow rate valve and the gas diffusion circulator.
3. Disconnect the circulating water lines, remove the reactor chain clamps, and carefully take out the used catalyst/membrane. Fully disassemble and clean all reactor components, then air-dry for storage.
4. Turn off the main power supply, circulating water bath power, and all other auxiliary equipment.
1. After completing the “Experimental Preparation” and “System Leak Check and Gas Purging” steps, inject the standard gas volumes corresponding to the first point of the calibration curve through the red standard gas port on the reactor.
2. Adjust the gas diffusion circulator to medium speed and operate for 10 minutes to ensure gas mixing.
3. Perform sampling and injection according to the “Sampling and Injection” procedure.
4. After injection, introduce the standard gas volume equal to the difference between the next calibration point and the previous one. Obtain chromatographic peak area data for at least five different standard gas concentrations.
5. In the chromatographic workstation, plot volume as the x-axis (X) and peak area as the y-axis (Y), and fit the working curve. The required linear correlation coefficient is R2 > 0.999.
6. After completing the experiment, shut down the system following the “Shutdown” procedure.
