The prepared -WO3/a-SiO2 nanofibers (calcined at 600 °C) were placed in an alumina combustion boat and were covered with another one to prevent the material from spilling out during evacuation (see Figure ). The boat with the sample was placed into a quartz tube and initially evacuated to reach a high vacuum (1.10 4 Pa) followed by setting up a partial hydrogen atmosphere by allowing hydrogen from the gas cylinder into the quartz tube and partially closing the valve into the vacuum pump system. By careful optimization of the inlet and outlet valves, the pressure was set to a constant value of 100 ± 5 Pa. The furnace was preheated at 800 °C and after reaching the desired temperature, the furnace was moved to the region of the quartz tube with the sample. In this way, shock calcination was performed for 1 h, followed by spontaneous cool-down to ambient temperature, venting, and collecting the resulting material for structural and chemical evaluation.