چكيده به لاتين
Today, the production of green hydrogen fuel through photoelectrocatalytic (PEC) water splitting has attracted great attention as a renewable energy source. Titanium dioxide nanotube arrays are also known as one of the most popular photocatalysts due to a number of unique features. In this work, titanium dioxide nanotubes arrays have been synthesized by the electrochemical anodizing method. One of the important parameters in the PEC water splitting system is the bias voltage, because if its value exceeds a specific limit, the water electrolysis process overcomes the process of photoelectrocatalytic water splitting. In the present study, the optimal bias voltage (0.7 v) was firstly determined using the two methods of Nernst equation and experimental data obtained from Chronoamperometry graphs. Titanium dioxide has a number of disadvantages including the recombination of photogenerated electron/hole pairs and also wide band gap, which reduce the rate of hydrogen evolution. In this study, chemical doping method was used to modify the titanium dioxide nanotubes array. For this purpose, two doping techniques 1) doping simultaneously along with anodizing, and 2) chemical bath deposition after anodizing were investigated once using tin chloride and then using combination of tin and zinc chlorides as doping and co-doping agents. With tin doping and compared to the reference sample, the hydrogen production rate was increased by 82.2% and 58.87% when doping was performed during anodizing and via chemical bath deposition, respectively. The maximum increase in rate of hydrogen production was about 84% achieved by the optimal sample co-doped with tin-zinc during anodizing.
