Bifunctional WO3 microrods decorated RGO composite as catechol sensor and optical limiter

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Herein, we report the one-pot synthesis of WO3/RGO composite and its efficient electrochemical activity in catechol (CC) oxidation. Anchoring of 1-D WO3 microrods on 2-D RGO nanosheets were confirmed through the detailed physicochemical analyses (XRD, FESEM, XPS, Raman). Availability of large electrocatalytically active surface area yields the conductivity enrichment as well as significantly improved redox properties in WO3/RGO composite. Further, a 20-fold intensified oxidation signal in CV and a 4-fold increased sensitivity from differential pulse voltammetry (DPV) support the superior electron transfer rate at the surface of WO3/RGO composite. Oxidation of CC involving the transfer of two electrons via a diffusion controlled process was revealed by the electrochemical approaches. From density functional theory (DFT) simulations, the charge transfer from O 2p orbital of catechol to W 4d orbital of WO3 facilitate the oxidation of catechol molecule. Z-scan study explored the strong reverse saturable absorption at 532 nm excitation and the third-order nonlinear optical susceptibility χ(3) of 9.727 × 10−8 esu was obtained for WO3/RGO. Hence, the hydrothermally prepared WO3/RGO composite with its excellent redox properties and negative nonlinearity could be a competent material to use in electrochemical sensing and optical limiting.