In-situ photochemical synthesis of Au nanoparticles in polymer matrix with one-component thioxanthone disulfide for detection of benzene, toluene and xylene vapours

•Dithioxanthone-disulfide was prepared as a new photoinitiator.•Thiyl radical formation was determined after photolysis of initiator.•Thiyl radicals helped for formation and stabilization of Au NPs.•In-situ formation of Au NPs in polymer matrix was achieved in one pot reaction.•Prepared nanocomposite films were used for BTX gas sensing and valuable results obtained for gas detection.