Enhanced photoelectrochemical performance using NiFe LDH as cocatalyst over Sn doped hematite
10th, April 2019, Wednesday, 4:30pm, ChE Seminar hall
Photo electrochemical (PEC) reactors offer a clean and sustainable way to store solar energy as chemical energy through the splitting of water into its primal form (H2 and O2). Among many metal oxides seen as candidates for this application, the characteristics of Hematite (α-Fe2O3), such as abundance, excellent chemical stability in an aqueous environment and favorable optical band gap, have helped it emerge as a promising photo anode. However, the poor optoelectronic properties necessitate a large application of overpotential for splitting water, limiting the high performance of this material. The efficiency of the photoanode material is determined by the light absorption, charge injection and charge separation efficiency as = abs×inj×sep. In this work, we have optimized the amount of Tin to be used as dopant at different dopant concentrations, viz; 1 %, 3 % and 5 %. Doping with 1 % Sn was found to give highest carrier density and improve charge separation efficiency, leading to the highest photocurrent among all dopant concentrations. To further improve the photocurrent and reduce the onset potential, we used NiFe layered double hydroxide as water oxidation cocatalyst to increase the charge injection efficiency of Sn doped hematite. An enhanced photocurrent density of 2.5 mA/cm2 at 0.8 V vs Ag/AgCl and 0.42 V shift in onset potential was recorded using NiFe LDH thin layer over Sn doped hematite.