Z-scheme photocatalyst for reduction CO2 to renewable fuels: a promising and powerful strategy to curb carbon footprints

Abstract

With rapid industrialization and modernization, the global energy demand has seen an exponential rise. These increasing demands are presently met using large scale depletion of non-renewable sources like fossil fuel and nuclear energy, which contribute to about 87% of total energy consumption. Over exploitation of fossil fuels have resulted in release of huge
amounts of greenhouse gas like CO₂. Thus, it is essential to drastically reduce CO₂ content in atmosphere as well as to develop other efficient methodologies to meet the energy demands that reduce the further emission of CO2. Out of all the existing methods, reduction of CO2 to renewable fuels is considered to be capable of addressing both the concerning issues. Studies has revealed that there are different type of semiconductor photocatalyst and each have their own pros and cons associated with them. Accounting the appealing properties like strong light harvesting ability, high redox potential, high charge-separation, and long durability that an efficient photocatalyst should possess, z-scheme photocatalyst is found to provide better capacities in photocatalytic activity and hence are explored more. This report gives an overview on different methods available to utilize CO₂ present in atmosphere, mechanisms followed for reduction of CO2 into different renewable fuels like CO, CH₄, CH₂OH and HCOOH, different types of photocatalyst with pathway followed by photogenerated electrons in these photocatalysts and different Z-scheme photocatalyst materials. This review also focuses on the design of a photoreactor that could support the whole process effectively and finally ends with a discussion on different characterization techniques available to confirm the formation of Z-scheme photocatalyst.