Photoactive metal chalcogenides towards CO2 reduction–a review

The enormous rise in population, urbanization, industrialization, and improvement in people’s living conditions over the past few decades have led to an increase in the consumption of fossil fuels. While there are several strategies to overcome it, such as afforestation, increasing the number of natural sinks, trapping the produced carbon dioxide in exhausted oil wells, and sorption of CO₂ on absorbers, all of these are only short-term remedies. However, a long-term solution would be conversion of CO₂ into another type of substance. Thereby, reduction of CO₂ to generate short chain hydrocarbons like CH₃OH, CH₄, C₂H₆, etc. can act as a renewable strategy to produce green energy sources. Reduction of CO₂ can be achieved following several pathways which include pyrolysis, chemical-catalysis, electrocatalysis and/or photocatalysis, etc. Among these routes, photocatalytic pathway is more appealing as it is an inherently green approach where solar light can directly convert CO₂ to value-added products. During molecular photocatalytic CO₂ reduction, typically Ru- or Ir-based photosensitizers are commonly used in presence of a cocatalyst. In this context, metal chalcogenides photocatalysts including CdS, CuS, MoS₂, ZnS, ZnTe, and their heterostructures like CdSe/CdS, CdS/CeO₂, etc. are made of earth-abundant metals and have received a considerable attention towards CO₂ reduction due to their notable photocatalytic efficiency. As it is well known, it is nearly impossible to concurrently satisfy the various performances in a one-step excitation system utilizing a single photocatalyst. As a result, the idea of composite photocatalysts which combine the advantages of many materials emerged, and this trend has become essential and foreseeable. This compact review highlights the application and the engagement of metal chalcogenides which due to their unique properties not only helps in the reduction of CO₂ but also plays a vital role in reducing environmental pollution and hence seen as a potential remedy towards the concerned problem.

Graphical Abstract

This compact review highlights the application and engagement of metal chalcogenides which due to their unique properties not only helps in the reduction of CO₂ but also plays a vital role in reducing environmental pollution. Various metal chalcogenides photocatalysts including CdS, CuS, MoS₂, ZnS, ZnTe, and their heterostructures like CdSe/CdS, CdS/CeO₂, etc. are made of earth-abundant metals and have received a considerable attention towards CO₂ reduction due to their notable photocatalytic efficiency.