Vol. 11, Issue 6 (2023)

The global climate risks and energy requirement issues have forced the world to adopt renewable resources and reduce the over-dependence on fossil fuel. Hydrogen is found to be the best alternative in current decades, and most of the countries are trying to explore it into technology within 2025. Industrial sources of environmental pollution generate huge amounts of industrial wastewater containing various recalcitrant organic and inorganic pollutants that are hazardous to the environment. And industrial wastewater can be regarded as a prospective source of energy and valuable raw materials for hydrogen production. Conventional sewage treatment systems are often not efficient enough for the complete degradation of pollutants and they are characterised by high energy consumption. The chemical energy that is stored in the wastewater is unexploited. A solution to these problems is the photo-electrocatalytic depletion of waste water to produce hydrogen which leads to energy generation. TiO₂ has been used as a photocatalyst since the 1970s due to its low cost, earth abundance, and stability. There has been a wide range of research activities in order to enhance the use of TiO₂ as a photocatalyst using dopants, modifying the surface, or depositing noble metals. Ligand-free semiconductor nano-composite of TiO₂ modified by Au is one of the best routes of water depletion techniques. This paper presents a general brief overview of the semiconductor Au doped TiO₂ materials applied as photoelectrodes in the treatment of wastewater. It deals with the alternative/cost-effective synthesis process of ligand-free Au/TiO₂ nano-composite, fundamentals of photo-electrocatalytic reactions and the mechanism of waste water treatment as well as parameters affecting the treatment process.

Graphical Abstract