Synthesis and photoelectrochemical properties of CdWO4 and CdS/CdWO4 nanostructures

•A facile CHM strategy is employed for the first time to synthesize CdWO4 nanowire and nanoflower arrays on cadmium foils.•The photoelectrochemical (PEC) properties are measured on the electrodes made of the CdWO4 nanowire and nanoflower arrays.•The photocurrent density of the nanowire electrode reaches 0.35mA/cm2, which is 3 times as much as that of the nanoflower electrode.•CdS nanoparticles are deposited on CdWO4 nanowire arrays to form a CdS/CdWO4 heterojunction to improve the PEC properties.•The remarkably enhanced photoresponse is achieved on the CdS/CdWO4 which is twice as much as that on the pure CdWO4 electrode. A facile composite-salt-mediated strategy is employed for the first time to synthesize CdWO4 nanowire and nanoflower arrays on cadmium foil substrates. The photoelectrochemical (PEC) properties are measured on the electrodes made of the CdWO4 nanowire and nanoflower arrays under the simulated sunlight illumination. Both electrodes display high sensitive response and photocurrent stability. The photocurrent density of the nanowire arrays electrode reach 0.35mA/cm2, which is about 3 times as much as that of the nanoflower array electrode. To improve the visible light photocurrent response, CdS nanoparticles are deposited on the CdWO4 nanowire arrays to form a CdS/CdWO4 heterojunction. Remarkably enhanced photoresponse is observed on the CdS/CdWO4 heterostructure and the photocurrent intensity is about twice as much as that of the electrode made of the pure CdWO4 nanowire arrays. The photoelectric mechanism is also discussed by the crystal structure and morphology characterization, optical band gap and carrier mobility analysis. This work presents a new design of a photoelectrochemical device for possible applications in photoelectrolysis of water and solar cells or highly sensitive light detection.