Semiconductor nanocrystals for small molecule activation via artificial photosynthesis

Facile activation and conversion of small molecules (e.g., H2O, CO2, N-2, CH4, and C6H6) into solar fuels or value-added chemicals under mild conditions is an attractive pathway in dealing with the worldwide appeal of energy consumption and the growing demand of industrial feedstocks. Compared with conventional thermo- or electro-catalytic approaches, the protocol of photocatalysis shines light on green and low-cost storage of sunlight in chemical bonds. For instance, artificial photosynthesis is an effective way to split H2O into molecular O-2 and H-2, thereby storing solar energy in the form of hydrogen fuel. Because of rational tunability in band gaps, charge-carrier dynamics, exposed active sites and catalytic redox activities by tailoring size, composition, morphology, surface, and/or interface property, semiconductor nanocrystals (NCs) emerge as very promising candidates for photo-induced small molecule activation, including H2O splitting, CO2 reduction, N-2 fixation, CH4 conversion and chemical bond formation (e.g., S-S, C-C, C-N, C-P, C-O). In this review, we summarize the recent advances in small molecule activation via artificial photosynthesis using semiconductor NCs, especially those consisting of II-VI and III-V elements. Moreover, we highlight the intrinsic advantages of semiconductor NCs in this field and look into the fabrication of prototype devices for large-scale and sustainable small molecule activation to store solar energy in chemical bonds.