Photochemistry and thermochemistry are two ways to store solar energy into chemical energy directly. For photochemical process, the major challenge is that the catalyst cannot absorb the full spectrum of solar energy, and just the energy in short-wavelength spectrum can be stored while the energy in long-wavelength spectrum is wasted. Therefore, photochemistry has not yet been found widespread industrial adoption, in spite of decades of active research, because the relatively low solar photochemical efficiency. For thermochemical process, it often operates at relatively high temperature to achieve reasonable product yield, requiring high ratio concentrators and large mirror fields. To achieve higher solar-to-chemical efficiency on relatively mild condition, photo-thermo synergetic catalytic chemistry is proposed. In this work, we synthesized different kinds of non-metal carbon nitride catalyst for photo-thermo catalytic hydrogen production from water. The hydrogen generation rate is experimentally tested on photo catalytic condition, thermo catalytic condition and photo-thermo catalytic condition. Results show that the photo-thermo catalytic reaction rate is much bigger than the sum of the photo catalytic reaction rate and thermo catalytic reaction rate, which verifies the synergetic effect between the photo catalysis and thermo catalysis with non-metal catalyst. This work would inspire a pathway toward the chemical storage of solar full-spectrum energy.
Keywords photo-thermo catalytic reaction; hydrogen production; solar full-spectrum storage; carbon nitride