Carbon-based nanostructures for emerging photocatalysis: CO2 reduction, N2 fixation, and organic conversion

Carbon materials have been studied extensively as components for photon energy conversion due to their low cost, unique electronic and optical properties. Elaborately designed carbon-based photocatalysts have facilitated the CO2 reduction reaction (CO2RR), the N2 fixation reaction (NFR), and the organic synthesis reaction (OSR) to realize an enhanced efficiency. The key factors affecting the activity and selectivity of photocatalytic reactions have been researched to ameliorate the performance of carbon-based photocatalysts. It has been concluded that several directions for future research provide promising guidance. The quest for carbon neutrality has become a major component of global climate governance. Significant efforts are focusing on alternative energy technologies to reduce the consumption of fossil fuels. Heterogeneous photocatalysis is considered promising as a green and sustainable technology to address important energy and environmental challenges. Due to their low cost and unique electronic and optical properties, carbon materials (including graphene, carbon nanotubes, carbon quantum dots, and carbon nitride) have been studied extensively as photocatalysts. In this review, we highlight the state-of-the-art of carbon-based nanomaterials used in emerging photocatalytic applications such as the CO2 reduction reaction (CO2RR), N2 fixation reaction (NFR), and organic synthesis reaction (OSR). The quest for carbon neutrality has become a major component of global climate governance. Significant efforts are focusing on alternative energy technologies to reduce the consumption of fossil fuels. Heterogeneous photocatalysis is considered promising as a green and sustainable technology to address important energy and environmental challenges. Due to their low cost and unique electronic and optical properties, carbon materials (including graphene, carbon nanotubes, carbon quantum dots, and carbon nitride) have been studied extensively as photocatalysts. In this review, we highlight the state-of-the-art of carbon-based nanomaterials used in emerging photocatalytic applications such as the CO2 reduction reaction (CO2RR), N2 fixation reaction (NFR), and organic synthesis reaction (OSR). one of the limited ranges within which the energy and momentum of an electron in a metallic crystal may vary continuously without any quantum jumps. the conduction band position of one semiconductor is more positive than the valence band position of another semiconductor in a heterojunction. a typical approach to the synthesis of graphene oxide using concentrated solution of H2SO4, NaNO3, and KMnO4. the conduction band and valence band position of one semiconductor are both more negative than another semiconductor in a heterojunction. the conduction band position of one semiconductor is more negative and the valence band position is more positive than another semiconductor in a heterojunction. a junction where the photogenerated electrons in the conduction band of one semiconductor migrate to recombine with the photogenerated holes in the valence band of another semiconductor.