By performing DFT calculations, we proposed new 2D materials, namely PdPX (X=S or Se) and investigated the possibilities of using them for water splitting. we have shown that 2D PdPX possess good stabilities and appropriate electronic and optical properties for solar driven water splitting. On basis of the investigation of PdPX for water splitting, we further explored the potentials of using Pd3P2S8 monolayer and bilayer to catalyze water splitting and studied the specific oxygen reduction process on surface of the catalyst. Our computations indicated that this 2D material can provide enough driven force for the oxygen reduction reaction, thus is an attractive candidate of photocatalyst. These two works have been published as academic papers (Chem. Eur. J. 2017, 23, 13612-13616; J. Mater. Chem. A, 2018, 6, 23495-23501) and the results are well disseminated to the academic communities. By accomplishing these two works, a mature research process in exploring the photocatalytic water splitting performance of 2D materials has been set up.
On the basis of the experimental knowledge of covalent organic frameworks in literature, we have designed several COFs built of hetero-triangulenes forming an intriguing Kagome lattice in two dimensions and systematically explored the structures and properties of them. According to our calculations, these 2D COFs show general electronic properties of hexgaonal and kagome lattices, while the band structures can be further determined by the hetero atoms. The resulting 2D kagome polymers have a characteristic electronic structure with a Dirac band sandwiched by two flat bands and are either Dirac semimetals (C center), or single-band semiconductors(B or N centers). Our investigations provide insights in designing 2D COFs with specific electronic properties and these design principles guide to screen desirable 2D COFs in experiments. This part of research has been published as an academic paper on an influential journal of chemistry (J. Am. Chem. Soc. 2019, 141, 2, 743-747).
We have further explored the possibilities of using the designed 2D COFs of D3 for water splitting. Extensive computations have been done to examine the band structures, optical properties and the specific oxygen reduction processes on surface of 2D COFs. According to our investigations, several 2D COFs can provide appropriate band edge alignment and pronounced light adsorption for water splitting. By comparing the front orbitals of the building monomers and the band edge of the corresponding 2D COFs, we further found the principle in designing possible photocatalysts of 2D COFs. This part of work has been mostly accomplished and will be submitted as an academic paper and disseminated to the academic communities soon.
