Pd quantum dot induced changes in the photocatalytic, electrocatalytic, photoelectrochemical and thermoelectric performances of galvanically synthesized Sb2Se3 thin films

We present a novel solution-based galvanic (electrochemical) synthesis of antimony selenide light absorber thin films on FTO (Fluorine doped tin oxide) coated glass substrates. The structural, surface morphological, compositional, optical and electrical properties of the samples were characterized using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Fast Fourier Transform (FFT), Energy Dispersive X-ray spectroscopy (EDS), UV-Vis and Photoluminescence (PL) spectroscopy and Electrochemical Impedance spectroscopy (EIS). X-ray Photoelectron Spectroscopy (XPS) was employed to determine the elemental state composition of as-deposited and annealed Sb2Se3 films containing Pd. The annealed Sb2Se3:Pd films exhibited hydrogen evolution in neutral buffer medium with small potential of 164 mV and a Tafel slope of 39 mV/decade. Pd incorporation enhances the efficiency towards HER performance, which shows the 10 mAcm- 2 current density at a low overpotential of 244 mV with reasonable durability. Photoelectrochemical (PEC) water splitting was observed at a potential of 0.41 V versus a reversible hydrogen electrode (RHE) with 3.2 mA cm-2 at 0 V versus RHE, under air mass 1.5 global illumination in a neutral electrolyte. To check the performance of this material for waste water treatment photodegradation of hazardous dyes and metal ion reduction experiments were performed. The photodegradation percentages of MG, MB and RhB dyes with annealed Sb2Se3:Pd thin film catalysts and H2O2 were 99.32% in 10 min, 98.95% in 20 min and 99.16% in 30 min, respectively. Cu2+ ions were photocatalytically reduced with the same catalyst to an extent of 98.9% in 20 min. Thermoelectric measurements on annealed Sb2Se3:Pd yielded the best Figure of merit and power factor values of 39.8 mu W/cmK2 and 10.81 x 10-3, respectively at 373 K.