Photocatalytic activity of electron-deficient and porous WO3 nanoparticles derived from thermal oxidation of bulk WC particles

• Porous WO3 particles were prepared by the thermal oxidation of bulk WC particle.
• Small and interconnected WO3 particles were formed with increasing calcination temperature.
• As-prepared WO3 samples were in an electron-deficient state (W+6−δ).
• The results were most favorable for WO3 particles calcined at 700 °C for O2 production and 600 °C for photocurrent.

Electron-deficient and porous WO3 particles were prepared by the simple thermal oxidation of commercial bulk WC. The crystal structure of as-prepared WO3 particles was monoclinic phases and its crystallinity and morphology were controlled by varying the calcination temperature. Small and interconnected WO3 particles were divided and formed from bulk WC particles with increasing calcination temperature. The electronic structure of thermally oxidized particles was studied by W LIII-edge XANES. Interestingly, as-prepared WO3 samples were in an electron-deficient state (W+6−δ). The photocatalytic performance of as-prepared samples was investigated in terms of oxygen production in AgNO3 aqueous solution and decomposition of the organic dye, Rhodamine B. The photoelectrochemical and photocatalytic activity were correlated and the results were most favorable for WO3 particles thermally oxidized at 700 °C for oxygen production and 600 °C for photocurrent production.