Construction of n-n heterojunction copper manganese spinel/mesoporous WO3 photocatalyst for efficient H2 evolution rate from aqueous glycerol

Abstract

Mesoporous metal oxides can expedite charge separation and mobility and give enormous active sites for H2 production. Herein, n-n heterojunction CuMn2O4/WO3 nanocomposites were constructed by a sol-gel procedure employing F-127 surfactant. The synthesized CuMn2O4/WO3 photocatalysts have been evaluated for H2 evolution from aqueous glycerol as an electron donor under visible illumination. XRD patterns of the synthesized CuMn2O4/WO3 nanocomposite manifested the formation of the monoclinic structure of WO3 and crystalline cubic CuMn2O4 spinel. The TEM image of WO3 NPs showed quasi-spherical ∼10–20 nm and CuMn2O4 NPs ∼10 nm were regularly dispersed on the surface of WO3. The optimum 12%CuMn2O4/WO3 nanocomposite exhibited a significant enhancement photocatalytic ability with the maximal H2 evolution rate (2856.6 μmol h−1g−1), which is about of 14.4 -fold higher than WO3 NPs. The optimal photocatalyst dosage is 2.4 g/L with a large evolution rate of 3427.2 μmol h−1g−1. The close interfacial connection existing between CuMn2O4 and WO3 with S-scheme mechanism and active charge separation generated the high H2 yield. The H2 evolution experiments for 45 h using CuMn2O4/WO3 nanocomposite are stable with high efficiency after five cyclings. This superb H2 evolution rate was utilized from the design of proper bandgap energy; the fostered light harvest, and the enhancement of separation efficiency photocarriers. The resultant CuMn2O4/WO3 nanocomposites exhibit a favorable photocatalyst for sustainability where it is effectively utilized in glycerol by-product through the renewable solar illumination to produce H2 and cleanly water concomitantly.