Fabrication of novel phosphotungstic acid functionalized mesoporous silica composite membrane by alternative gel-casting technique

► HPW/MCM-41 composite membranes have been fabricated by a gel-casting technique. ► HPW/MCM-41 composite membranes can operate stably below 200 °C. ► A single cell can be assembled using the HPW/MCM-41 membrane. ► A maximum output power density of 101 mW cm−2 in MeOH/air at 150 °C was observed.