Nanostructured p-PbS/p-CuO sulfide/oxide bilayer heterojunction as a promising photoelectrode for hydrogen gas generation

Recently, the photoelectrochemical (PEC) water-splitting reaction for hydrogen (H-2) production has been a competitive research route to realize clean and sustainable electric power. In this work, copper oxide (CuO) and PbS thin films were fabricated on commercial glass, respectively, using the techniques of successive ionic-layer adsorption and reaction and chemical bath deposition. These nanostructured thin films served successfully as photoelectrodes for the photogeneration of H-2. In addition, a p-PbS/p-CuO bilayer system was also fabricated, and a remarkable boost in PEC efficiency was observed compared to pure CuO and PbS thin films. Optical examinations showed excellent absorbance properties of the p-PbS/p-CuO bilayer in the visible range, with a bandgap of similar to 1.28 eV. X-ray diffraction analysis indicated a monoclinic CuO/cubic PbS crystalline structure with a particle size of similar to 18 nm. The photocurrent density (J (ph)) values were obtained using a three-electrode electrochemical cell in 0.3 M Na2S2O3 electrolyte. The p-PbS/p-CuO photoelectrode demonstrated a J (ph) value of -0.390 mA cm(-2), which is significantly higher than the values of -0.120 and -0.008 mA cm(-2) for the pure PbS and CuO photoelectrodes, respectively. This improvement is attributed to the p-PbS/p-CuO oxide/sulfide bilayer heterojunction, which improved the visible light absorption and reduced the electron-hole (e-h) recombination. The effects of pH value, temperature light intensity, and wavelength were all additionally studied. Remarkably, the photoelectrodes were stable under a pH of similar to 7, which makes them promising for H-2 production using normal drinking/seawater. These findings confirm the ability of the prepared photoelectrodes to facilitate water splitting and H-2 generation under various environmental, chemical, and illumination conditions.